Note: Descriptions are shown in the official language in which they were submitted.
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AN IMPROVED METHOD OF TRANSPORTING AND STORING WIND
GENERATED ENERGY USING A PIPELINE
Field of the Invention
The present invention relates to a method of transporting and storing wind
generated energy, and in particular, to a method of transporting and storing
wind
energy in the form of compressed air, via a pipeline.
Background of the Invention
Generating energy from natural sources, such as sun and wind, has been an
important objective in the United States and across the world over the last
several
decades. Reducing reliance on oil, such as from sources in the Middle East,
has
become an important world-wide issue. Energy experts fear that these
resources,
including oil, gas and coal, will someday run out. Because of these concerns,
many
projects have been initiated in an attempt to harness energy derived from what
are
often called natural "alternative" sources.
Wind farms, for example, have been built in areas where the wind naturally
blows. In many areas, a large number of wind turbines are built and "aimed"
toward
the wind, wherein rotational power is created and used to drive generators,
which in
turn, generate electricity. Wind farms are most efficiently operated when wind
conditions are relatively constant and predictable. Such conditions enable the
supply and delivery of energy generated by the wind to be consistent, thereby
avoiding surges and swings that can adversely affect the system. Failure to
properly
account for these conditions can result in power outages and failures, wherein
a
failure in one area of the grid could cause the entire system to fail, i.e.,
an entire
regional blackout can occur.
The difficulty of operating wind farms, however, is that wind by its very
nature
is inconsistent and unpredictable. In many cases, wind speeds, frequencies,
and
durations vary considerably, i.e., the wind never blows at the same speed over
a
period of time, and wind speeds can vary significantly from one moment to
another.
And, because the amount of power generated by wind is mathematically a
function
of the cube of the wind speed, even the slightest fluctuation or oscillation
in wind
speed can result in a disproportionate change in wind-generated power.
These conditions can lead to problems. For example, in the context of a wind
farm delivering energy to an electrical power grid, which is a giant network
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composed of a multitude of smaller networks, these sudden surges in one area
can
upset other areas and can even bring down the entire system in some cases.
Also,
if a wind farm is dedicated to providing energy to a community or facility,
the same
surges can cause overloads that can damage components connected to the system.
Another problem associated with wind fluctuations and oscillations relates to
the peak power sensitivity of the transmission lines. When wind speed
fluctuations
are significant, and substantial wind power output fluctuations occur, the
system
must be designed with enough line capacity to withstand these occurrences. At
the
same time, if too much consideration is given to peak power outputs, the
system
could be over-designed, in which case, during normal operating conditions, the
system may not operate efficiently, thereby increasing the cost of energy.
Another related problem is the temporary loss of wind power associated with
an absence of wind or very low wind speed in some circumstances. When this
occurs, there may be a gap in wind power supply, which can be detrimental to
the
overall grid power output. This is especially important during high demand
periods,
such as during periods when heating and cooling requirements are normally
high.
Because of these problems, attempts have been made in the past to store
energy produced by the wind so that wind generated energy can be used during
peak demand periods, and/or periods when little or no wind is available.
Utility
companies and other providers of energy have, in the past, implemented certain
time-shifting methods, wherein energy available during low demand periods is
stored, and then used later during peak demand periods. These methods
typically
involve storing energy, and then using that energy later, to supplement the
energy
that is otherwise available.
Several such energy storage methods have been used in the past, including
compressed air energy storage systems, such as underground caverns and tanks.
Thus far, hovuever, one of the main disadvantages of such systems is that they
are
relatively energy inefficient. For example, compressed air energy systems have
a
tendency to lose a significant portion of the stored energy when converting
the
compressed air energy to electrical energy, wherein the energy used from
storage
ends up costing more than the energy that was stored, i.e., just converting
compressed air energy into electrical energy often results in a substantial
loss of
energy. These inefficiencies can make it so that the economic incentives
required to
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install energy storage systems of this kind are significantly reduced. Past
systems
have not been able to reduce the inefficiencies, as well as the fluctuation
and
oscillation problems discussed above, inherent in using wind as an energy
source.
Another problem associated with wind energy is that even if wind farms are
located where the wind is more predictable and constant, and, even if storage
facilities are constructed, there is the additional problem of getting the
energy to
where the energy is needed. In many cases, wind farms are located far from
existing power grids, and far from communities and facilities where energy is
needed, i.e., the ideal location for a wind farm may be on top of a hill, or
mountain, or
in a canyon, or the desert, or somewhere offshore, etc., which can be many
miles
from the site that needs the power. In such case, it would be extremely
expensive to
build power transmission lines to transmit electrical power generated by the
wind
farm, just to service the wind farm. Not only could there be significant costs
associated with building storage tanks, i.e., to store energy as discussed
above, but
there would be an even greater cost associated with constructing new
transmission
lines that will have to extend great distances. Right-of-way costs will also
be
incurred, i.e., it is often necessary to obtain permission from local
communities,
wherein the process of obtaining approval can be time consuming and costly.
When conventional power transmission lines are involved, and used to
transmit energy over long distances, there is the additional problem of line
losses.
This has become an increasing problem throughout the United States and is
likely to
be an issue world-wide. For example, despite the many thousands of miles of
high
voltage electric transmission lines that have been built over the last few
decades, the
rate of building new transmission lines has actually decreased, while the
demand for
electricity has continued to increase. In fact, according to some statistics,
annual
investment in new transmission facilities has declined over the last 25 years,
wherein
the result has been excess grid congestion, and bottlenecking, which has led
to
higher electricity costs, i.e., due to the inability of customers to access
lower-cost
electricity supplies, and because of higher line losses.
Line losses are often related to how heavily the system is loaded, and
inherent to wiring properties and conditions used to transmit the energy. In
fact,
transmission and distribution losses in the United States were at about 5% in
1970,
but have increased to about 9.5% in 2001, due to increased energy demand
without
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an adequate increase in transmission facilities. These losses are caused by
congested transmission paths that can affect various aspects of the grid,
wherein it is
estimated that power outages and quality disturbances have cost the United
States
economy up to $180 billion annually.
Another related problem is that throughout the United States and likely in
other countries, the highest demand for energy often occurs during the day,
and
therefore, the demand for electrical energy during the most high-demand period
continues to increase. These peak demands can place a heavy burden on utility
plants and grids that supply electrical power, wherein they often have to be
constructed to meet the highest demand periods, which means that during the
low
demand periods, they will inevitably operate inefficiently, i.e., at less than
peak
efficiency and performance. This means that not only must the transmission
lines be
built to withstand the highest demand periods, but the utility plants
themselves must
be designed to generate enough energy during the peak demand periods, even if
those periods only occur during a small fraction of the time each month. This
is
because the transmission lines themselves do not store energy, i.e., they are
merely
energy "conduits," and therefore, the utility plants must be able to produce
and
supply the higher amounts of energy. Failure to properly account for such high
demand periods, such as by over-designing the facilities to meet the peak
demands,
can result in the occurrence of frequent power outages and failures, and
increased
costs.
These demands can also place expensive burdens on customers that need to
use energy during the peak demand periods, including many commercial and
industrial property owners and operators. Utility companies often charge a
significant premium on energy consumed during peak demand periods. This
practice is genera(Ey based on the well known principles of supply and demand,
e.g.,
energy costs are higher when demand is high, and less when demand is low. And
because most commercial and industrial property owners are forced to operate
during the day, they are most often forced to pay the highest energy costs
during the
highest demand periods.
Utility companies also charge for peak power usage during peak demand
periods by assessing a penalty or surcharge (hereinafter "demand charge") on
the
maximum rate of consumption of power that occurs during a predetermined
period,
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such as during a one month period. A demand charge may be assessed, for
example, based on the maximum "peak" rate of consumption that occurs during a
short spike or surge, wherein the demand charge can be assessed regardless of
how short the "spike" or "surge" might be during that period, and regardless
of what
rate may apply immediately before and after the spike or surge. This demand
charge can also be assessed regardless of the average consumption rate that
may
have been in effect during the period, which could be considerably lower than
the
peak. Even if the overall average rate of use is substantially lower, the
demand
charge can be based on a much higher spike or surge, experienced for a very
short
time during that period.
These pricing practices are designed to help utility companies offset and/or
recover the high cost of constructing utility power plants and grids that are,
as
discussed above, designed to meet the peak demand periods. They also encourage
commercial and industrial property owners and operators to reduce energy
consumption during peak periods, as well as to try to find alternative sources
of
energy, if possible. Nevertheless, since most commercial and industrial
property
owners and operators must operate their businesses during the day, and
alternative
sources of energy are not always readily available, they often find themselves
having
to use energy from the grid during the highest rate periods. Moreover, because
energy consumption rates can fluctuate, and surges and spikes can occur at
various
times, potentially huge demand charges may be applied.
Summary of the Invention
Despite the many good intentions of energy producers across the United
States and in other countries who have encouraged the use of alternative
energy
sources, the bottom line is that, barring government subsidies, the cost of
producing
the energy must be such that it makes long term economic sense to construct
the
facilities needed to produce, supply and deliver energy to consumers.
In this respect, most populated areas of the United States have adequate
access to electrical power grids that supply energy produced by local utility
companies, and are also willing to pay the cost of tapping into the existing
grids.
Except for those few instances where power outages might occur, most energy
consumers have come to expect that they can simply connect to and obtain power
from the nearest grid.
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In some remote areas of the country, however, electrical power is not always
readily available, and efforts must be made to supply needed power to those
areas.
For example, new electrical transmission lines, which are costly to install,
may be
required to enable facilities, and people who live and/or work in areas remote
from
the power grid, to receive access to electrical power. Nevertheless, the cost
of
constructing electrical transmission lines, from the site to the nearest power
grid, can
be prohibitively high. To make matters worse, these costs must often be
incurred by
end-users, such as when private non-governmental developments and facilities
are
involved. And, once the connection is made, they must continue to pay the
utility to
use the energy.
Nevertheless, due to the increasing cost of land, and the need to sell
products
that are competitively priced, many industrial facilities are seeking to
locate their
factories and other industrial complexes in remote locations, where the cost
of
owning and/or leasing land is still affordable, and where low priced skilled
labor
might still be available. While there are additional costs associated with
constructing
these types of facilities, including traveling to and from the location, in
many cases,
the decision to build and operate such facilities can make economic sense.
One problem associated with locating the facilities so far from the power
grid,
however, is the cost of connecting the facility to the power grid, to obtain
the energy
needed to operate the facility in an economical manner. In many cases, such as
when a new factory is built, a new power transmission line must also be built,
to
connect to the grid, which, as discussed above, can be prohibitively costly.
Due to
the labor intensive nature of line installation, in many cases, the cost of
installing a
low capacity line can be almost as high as installing a medium to high
capacity line.
These costs can be a particular burden when the demand for energy at the
facility is
relatively small, i.e., compared to the capacity of the line, in which case,
the power
transmitted through the line may never reach its capacity.
These issues are compounded by the fact that the energy must. still be
purchased from the utility company that supplies energy to the grid. In such
case,
depending on how much energy is used by the facility, and when, i.e., during
peak
demand periods, the costs associated with using energy from the grid can be
significant. As discussed above, the facility may be required to pay peak
energy
rates, which can occur when energy demand is at its highest, i.e., during the
peak
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day-time hours. Additional demand charges, as discussed above, can also be
incurred.
Energy losses attributed to connecting to the grid and extending the
transmission line a long distance can also erode the efficiencies of the
system and
increase the cost of operation. Typically, while transmission lines are
capable of
transmitting large amounts of electrical energy, a significant amount of
energy can
be lost during the transmission, especially when great distances are involved.
In one aspect, the present invention relates to an improved method of storing
wind generated energy in the form of compressed air, via a pipeline, at a
remote
location where wind energy is naturally available, and then transporting the
compressed air energy, via the same pipeline, to a community or facility in
need of
the power, whether remote from the grid or not. It preferably comprises a
series of
compressors, and a relatively long pipeline, with one or more turbo expanders
and/or
generators servicing the community or facility, wherein the energy supplied by-
the
pipeline can then either become the exclusive power source, or can supplement
the
power from the grid.
In a first configuration, the compressed air energy in the pipeline is used to
drive a turbo expander, which is connected to a generator, such that
electricity can
be generated, which can be used by the end user community or facility. In
addition,
the waste chilled air by-product that is co-generated along with the
electricity can be
used for other purposes. For example, the waste chilled air from the turbo
expander
can be used for refrigeration and air conditioning purposes, at the community
or
facility, which is especially helpful when the system is located in warm
climate areas.
In such case, no additional heat source is provided, such that the system can
take
full advantage of the waste chilled air co-generated as the compressed air is
released.
In this embodiment, not only is electricity generated, but the system
preferably
produces maximum chilled air, which can be used not only for refrigeration and
air
conditioning purposes, but also for desalination purposes. The desalination
systems
that are contemplated to be used in conjunction with the present invention are
those
that utilize chilled air to freeze water, which effectively helps to separate
and remove
contaminants found in water, thereby producing fresh drinking water. A thermal
energy storage system can also be used to store the chilled water generated by
the
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chilled air in a supplemental storage unit for later use. These embodiments
are well
suited for warm weather climates, such as in deserts, where access to fresh
drinking
water supplies is difficult.
In connection with this first embodiment, another version can be provided
where only chilled air is produced, using a turbo expander specifically
adapted to
provide only cooling for the facility, i.e., no electricity is produced. This
can be used,
for example, where there is adequate energy available from the grid for the
facility to
operate, but the facility needs a low cost source to drive the air
conditioning units.
In a second configuration, heating is provided on a limited basis to enhance
the production of electricity. For example, in this embodiment, the preferred
heat
source is the waste heat generated by the compressors as the air is being
compressed, which can be distributed back into the pipeline to heat the
compressed
air. In this embodiment, while a heating unit is used, an effort is made to
eliminate
the use of any additional energy source, which would require more power to
operate.
This embodiment also has the advantage of being able to generate, in addition
to
electrical power, a certain amount of chilled air as a by-product. Like the
first
embodiment, this embodiment preferably takes advantage of the chilled air co-
generated by the turbo expander, i.e., as the compressed air is released, to
provide
chilled air for cooling purposes, except in this embodiment, the chilled air
is not as
cold, due to the added waste heat from the compressors.
In a third configuration, various heat sources, including waste heat from the
compressors, and heater units, can be provided, as the compressed air is
released,
to maximize the generation of electricity by the generator, but at the expense
of
generating no chilled air. In this embodiment, it is contemplated that at
least one of
three different types of heating systems can be used as a means of providing
heat to
the compressed air, including 1) solar thermal collectors to utilize energy
from the
sun, including painting the pipeline black, and locating the pipeline in
direct sunlight,
such as on the desert floor, to make use of the sun's heat, 2) waste heat
collectors to
circulate the waste heat generated by the compressors to the compressed air
stored
in the pipeline, and 3) a separate heating unit, such as a fossil fuel burner,
to
introduce heat into the pipeline, or add heat to the turbo expander input as
compressed air is being released by the turbo expander. The invention also
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contemplates using other methods of providing heat to the compressed air, such
as
combustors, etc., if desired.
In a fourth configuration, in addition to, or instead of, producing electrical
energy, the system can be adapted to provide power in the form of compressed
air
energy, to drive pneumatic equipment, including tools and machinery, etc. In
this
respect, the pipeline can be adapted to provide energy to a facility that
normally
operates pneumatically driven equipment, wherein the compressed air energy in
the
pipeline can be used directly, without having to convert the compressed air
energy
into electricity first, thereby improving the efficiencies of the system. In
this
embodiment, the compressed air energy can be used to supplement the electrical
energy available from the grid, i.e., the compressed air energy can be used to
operate the pneumatic equipment, whereas, electricity from the grid can be
used for
other functions, in which case no electricity has to be produced from the
compressed
air energy. Alternatively, the system can have means to generate electricity
from the
compressed air energy, in addition to driving the pneumatic equipment, so that
the
facility would not need to be connected to the grid. In such case, the system
can be
adapted to switch between using the compressed air energy to generate
electricity,
on one hand, and driving the pneumatic equipment directly, on the other. They
can
also be simultaneously generated.
In a fifth configuration, in addition to, or instead of, incorporating a wind
farm
to produce the compressed air energy for the pipeline, the pipeline system can
be
connected to an existing power source, such as a utility, i.e., geothermal
plant,
nuclear power plant, hydroelectric plant, etc., or grid, wherein the system
can be
designed to compress air and store energy during low demand periods, such as
at
night, and use the stored energy during high demand periods, such as during
the
day. This way, the utility can continue to operate at its most efficient
levels, and at a
constant load level, and can store the energy that is produced at night when
the
demand is low, to supplement the energy needed during the high demand periods.
From the standpoint of energy production, with this embodiment, the utilities
are able to provide more energy during the high demand periods, without
necessarily
having to construct larger and higher capacity power generation facilities,
which
would be more costly to do. Also, the utility is able to produce energy at
consistently
high levels, and at a constant rate, throughout the day and night, to maximize
the
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efficiency of the facility. The system is preferably able to supply
uninterrupted and
stabilized power to the end user. Further, the utility is able to charge more
for the
energy used during the high demand periods, even though the energy is produced
during the low demand, low cost, periods. From the standpoint of the user, the
system can be developed so that the energy rates during the high demand
periods
are lower, and so that there are fewer surges, spikes and outages.
In a sixth configuration, one or more of the features described above in
connection with the first five configurations can be incorporated into a
single system,
and can be used to provide energy to multiple communities and/or facilities
along the
length of the pipeline. For example, when the system is located in a hot
desert, and
services a facility using pneumatic equipment, the system can be installed
without a
heating element, so that the system can co-generate electricity and chilled
air for air
conditioning purposes. The system can also be set up to use the compressed air
to
drive the pneumatic equipment, thereby increasing the overall efficiencies.
Likewise,
the system can be adapted so that compressed air energy can be generated by
both
a wind farm and utility - due to the uncertainties associated with using wind
as a
power source, it is often advantageous to provide a secondary source of
energy,
such as power from a utility or grid.
One aspect of the present invention- relates to the use of a pipeline system
(either aboveground or underground) into which the compressed air from the
wind
turbines can be distributed, wherein the pipeline can be used to not only
store the
compressed air, but also transport the compressed air energy from one remote
location (such as where wind conditions are ideal) to where the energy is
needed (a
facility or community in need of the power). Storage of compressed air in this
manner alloWs the energy derived from the wind to be stored for a period of
time until
it is needed. The pipeline can also be used as a means of transporting the
stored
energy, such as from where the wind farm is located, to the location where the
energy is needed, wherein the pipeline itself can serve as both storage and
transport
means.
A benefit to using this type of system is that the transmission means, which
in
this case is a pipeline, has the ability to not only transport energy from one
location
to another, but also to store energy. This way, unlike conventional power
lines,
which can only transmit power through a conduit, a predetermined amount of
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can be stored so that energy will be available, even if energy at the source
becomes
temporarily unavailable, i.e., the wind stops blowing, or the utility shuts
down. It can
also store energy produced during low demand periods, such as at night, so
that it
can be distributed and used during high demand periods, when the energy rates
are
higher. In such case, the system will be able to continue to supply energy to
the end
user for a predetermined amount of time, at a lower cost.
Another aspect of Applicant's invention takes into account the following:
When determining the location of the wind farm, as well as where the pipeline
is to
be located, the method preferably takes into account existing roads,
easements,
underground pipes, railroad tracks, lines, cables, etc., and where they are
located,
so that the pipeline can be laid along the most economical and/or convenient
path
possible. That is, the pipeline is preferably located along a direct line or
path
extended along, or at least in close proximity to, existing roads, railroad
tracks,
easements, pipes, conduits, cables, etc., so that new roads, access, and open
areas, etc., do not have to be built, and so that existing easements, land use
permits,
environmental impact reports, etc., can be used or relied upon to install the
pipeline.
In fact, where there are abandoned pipe systems, such as natural gas or sewer
lines, the present invention contemplates connecting to, or using the existing
pipes,
in whole or in part, as well as their easements, access areas, roads, etc., to
more
economically install the pipeline system.
In one embodiment, the present invention contemplates constructing the
pipeline so that it is adjacent or connected to an existing railroad track, by
positioning
and connecting the pipeline directly onto or adjacent the railroad ties. That
is, the
present invention contemplates taking advantage of the easements and network
of
railroad tracks that have been constructed throughout the country, which often
extend to remote locations, to construct the pipeline at a reduced cost, and
in a more
efficient manner. The invention preferably comprises using connectors to
connect
the pipeline to the railroad ties themselves, such as above ground, with the
pipeline
extending parallel to the tracks, so that maintenance work can easily be
performed
on the pipeline, by traveling along the tracks. This way, the pipeline will
not need to
be buried in the ground, so as to reduce the cost of installation, and
maintenance.
The present invention also contemplates constructing the pipeline along the
desert floor, exposed to the hot sun, so that the pressure inside the pipeline
can be
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advantageously increased due to the sun's heat. In this respect, it can be
seen that
there are advantages to locating the pipeline along an existing railroad
track, which
also extends through the desert, such that the sun can help increase the
pressure
inside the pipe, wherein additional energy can be generated when released.
In this respect, another synergistic effect contemplated by the present
invention is locating the industrial facility in the desert, where chilled air
created as
compressed air energy is released can be used to supplement the air
conditioning
capabilities of the facility. This allows the facility to reduce its reliance
on electrical
energy, to power air conditioning units, thereby effectively increasing the
overall
efficiencies of the system.
Brief Description of the Drawings
Figure 1 shows a wind farm located in a remote location connected by a
pipeline system extending along a planned route, such as along an existing
road or
easement, between the wind farm and end user, which can be a community,
facility
or grid, whereby compressed air energy from the wind farm can be stored and
transported by the pipeline to the community, facility or grid;
Figure 2 shows two wind farms located in remote locations connected by a
pipeline system extending along a planned route, such as along an existing
road or
easement, between the wind farms and end user, which can be a community,
facility
or grid, wherein additional windmill stations are provided along the planned
route to
provide intermittent sources of compressed air energy to maintain air pressure
in the
pipeline along the planned route;
Figure 3 shows a wind turbine with a schematic view of how energy is
extracted from the wind turbine, via an electric motor, and generator, to
drive a
compressor which supplies compressed air energy into the pipeline system;
Figure 4 shows several pipeline embodiments, including a pipeline system
located underwater, along the desert floor, and adjacent a railroad track (and
connected to the railroad ties), and mentions a preferred length of pipe,
i.e., 100
miles long, and preferred pipe size (3 to 4 feet in inside diameter); and
Figure 5 shows a schematic drawing of a variable use system incorporating
some of the features of the present invention, wherein the compressed air
energy
from storage can be used to supply energy directiy to operate pneumatic
equipment,
generate electricity via a turbo expander, and provide chilled air co-
generated as the
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electricity is produced, for cooling purposes, i.e., to operate air
conditioning
equipment, wherein waste heat and a burner unit are provided as optional means
of
heating the compressed air before being released by the turbo expander;
Figure 6a shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with pneumatic equipment, wherein the
pipeline is 100 miles long, and 4 feet in inside diameter, and wherein energy
is
produced by a geothermal, diesel or nuclear power plant, and compressed air
energy in the pipeline is stored at night, so that it can be used during the
day;
Figure 6b shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with a combination of pneumatic
equipment,
and electrical and air conditioning needs, wherein the pipeline is 100 miles
long, and
4 feet in inside diameter, with various energy sources, but wherein the
farthest
industrial park with electricity and air conditioning needs is only 25 miles
away from
the energy source, and wherein industrial parks with pneumatic equipment can
be
located as far as 100 miles away, based on the amount of energy losses
attributable
to energy usage, as shown in Figure 11. Note: In this case, the remaining 75
miles
of pipeline can be smaller in size, such as 3 feet in inside diameter, if the
pneumatic
equipment demands from the industrial parks can be met with a 3 feet pipe,
despite
the greater pressure losses;
Figure 6c shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with air conditioning needs, wherein
the
pipeline is 100 miles long, and 4 feet in inside diameter, and wherein energy
is
produced by a geothermal, diesel or nuclear power plant, and compressed air
energy in the pipeline is stored at night, so that it can be used during the
day;
Figure 6d shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with desalination facilities and air
conditioning needs, wherein the pipeline is 100 miles long, and 4 feet in
inside
diameter, and wherein energy is produced by a geothermal, diesel or nuclear
power
plant, and compressed air energy in the pipeline is stored at night, so that
it can be
used during the day, and wherein the end user installs the turbo compressor,
turbo
expander, and desalination system for their own industrial park;
Figure. 7a shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with pneumatic equipment, wherein the
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pipeline is 100 miles long, and 4 feet in inside diameter, and wherein energy
is
produced by a wind farm and energy from the wind is stored in the pipeline;
Figure 7b shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with a combination of pneumatic
equipment,
and electricity and air conditioning needs, wherein the pipeline is 100 miles
long, and
4 feet in inside diameter, and wherein energy is produced by a wind farm, but
wherein the farthest industrial park with electricity and air conditioning
needs is only
25 miles away from the wind farm, and wherein industrial parks with pneumatic
equipment can be located as far as 100 miles away, based on the amount of
energy
losses attributable to energy usage, as shown in Figure 11, and the end user
can
install the turbo generator to supply pneumatic, electric and air
conditioning. Note:
In this case, the remaining 75 miles of pipeline can be smaller in size, such
as 3 feet
in inside diameter, if the pneumatic equipment demands can be met with a 3
feet
pipe, despite the greater pressure losses;
Figure 7c shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with air conditioning needs, wherein
the
pipeline is 100 miles long, and 4 feet in inside diameter, and wherein energy
is
produced by a wind farm and stored in the pipeline, and the end user can
install the
turbo compressor and turbo expander to provide air conditioning;
Figure 7d shows a schematic drawing of an embodiment where a pipeline is
used to service several industrial parks with desalination facilities and air
conditioning needs, wherein the pipeline is 100 miles long, and 4 feet in
inside
diameter, and wherein energy is produced by a wind farm and stored in the
pipeline,
and wherein the end user installs the turbo compressor, turbo expander, and
desalination system for their own industrial park;
Figure 8 shows a schematic drawing of an example of a pipeline that is 100
miles long, is 4 feet in diameter, and has .1,200 psig pressure therein, with
various
energy sources attached, including a wind farm, geothermal and nuclear, and
various end users, including an industrial park, with pneumatic equipment, and
a
desalination plant;
Figure 9 shows a schematic drawing of a system having a turbo compressor
and a turbo expander for generating chilled air;
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Figure 10 shows charts graphically indicating the level of turbo expander
expansion and efficiency as air temperatures are increased;
Figure 11 shows a chart graphically indicating the amount of pressure loss
that can be experienced within the pipeline, as a function of the pipe
diameter, the
pressure inside the pipeline, and the manner in which the compressed air is
used,
i.e., either for generating electricity (where pressure and velocity is
relatively high) or
driving pneumatic equipment (where pressure can be relatively low); and
Figure 12 shows a comparison between the electrical generation system and
the pneumatic equipment driving system graphically displayed in Figure 11,
wherein
a 100 mile pipeline, that is 3 feet in inside diameter, with about 1,200 psia
pressure,
is used to compare how long the pressure inside the pipeline will last, when
no
additional pressure is added to the pipeline.
Detailed Description of the Invention
One preferred aspect of the present invention relates to wind powered energy
generating and storing systems capable of transporting wind generated energy
from
areas where wind conditions are ideal, to areas where energy is needed, as
shown
in Figures 1 and 2, without having to extend lengthy and expensive power
transmission lines, and without having to build expensive compressed air
storage
tanks, etc. In this aspect, the present system preferably comprises selecting
an area
where the wind conditions are likely to be consistent and predictable, or at
least
more so than other areas that are available, which would be suitable for
generating
wind energy. By their very nature, these areas are often located in remote
areas
many miles from communities where people live, and far from existing power
grids.
They may, for example, be located in deserts, canyons, offshore areas, and on
mountaintops or hilltops far from civilization. They are also often located
where
property values are relatively low.
Another preferred aspect of the present method encompasses making use of
wind energy in preferred or ideal conditions, by locating one or more wind
turbines in
locations where wind conditions are ideally suited to generating a consistent
and
predictable amount of energy. Although all locations suffer from some
unpredictability and uncertainty, there are clearly locations that are better
than
others, and the present method preferably takes into account the use of these
preferred locations.
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Another preferred aspect of the present invention relates to the use of at
least
one wind turbine, as shown in Figure 3, that is either 1) dedicated to
generating
electricity to operate at least one compressor (hereinafter "electrical wind
turbine"),
or 2) dedicated to generating mechanical rotational energy to drive at least
one
compressor mechanically (hereinafter "mechanical wind turbine"). Each of the
wind
turbine types is preferably dedicated to generating compressed air energy that
can
be stored in the pipeline system. Preferably, the system is designed with a
predetermined number of wind turbines, based on the amount of power needed by
the end user facilities and communities, as well as a determination of the
size and
length of the pipeline that will be used, to service areas that are remote
from the
wind farm. Preferably, the system is both economical and energy efficient in
generating the appropriate amount of energy.
Each electrical wind turbine type preferably has a horizontal axis wind
turbine
(HAWT) and an electrical generator located in the nacelle of the windmill,
such that
the rotational movement caused by the wind is directly converted to electrical
energy
via an electric motor and generator, as schematically shown in Figure 3. This
can be
done, for example, by directly connecting the electrical generator to the
horizontal
rotational shaft of the wind turbine so that the mechanical power derived from
the
wind can directly drive the generator. The generator in turn can be used to
drive a
compressor, which generates compressed air energy, which can be stored in the
pipeline.
The mechanical wind turbine type is somewhat more complex in terms of
bringing the mechanical rotational energy from the high above-ground nacelle
down
to ground level as rotational mechanical energy. The horizontally oriented
wind
turbine of each station preferably has a horizontal shaft connected to a first
gear box,
which is connected to a vertical shaft extending down the wind turbine tower,
which
in turn, is connected to a second gear box connected to another horizontal
shaft
located on the ground. The lower horizontal shaft is then preferably connected
to the
compressor, such that the mechanical rotational power derived from the wind
can be
used to mechanically drive the compressor, which produces compressed air
energy.
This mechanical energy can be used to drive the compressor directly, without
having to convert the mechanical energy into electricity first. By locating
the
compressor downstream of the gearbox on the shaft, and by using the mechanical
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rotational energy of the wind turbine directly, energy losses typically
attributed to
other types of arrangements can be avoided. The power generated by each
mechanical wind turbine can be used to directly power at least one compressor,
which can be used to compress air energy into the pipeline system.
Nevertheless,
there are inherent problems associated with transmitting wind power via a
vertical
shaft, which tends to vibrate due to resonance along the long shaft, wherein
the
vibrations should be controlled for the system to function properly.
The compressed air energy generated by each wind turbine is preferably
distributed into the pipeline, via one or more compressors. Storage of
compressed
air energy allows the energy derived from the wind to be stored for an
extended
period of time. By storing energy in this fashion, the compressed air can be
released
and expanded at the appropriate time, such as when little or no wind is
available,
and/or during peak demand periods. The released and expanded air can then be
used to supply energy derived from the wind to generate electrical power on an
"as
needed" basis, i.e., when the power is actually needed, which may or may not
coincide with when the wind actually blows.
The present invention uses a pipeline system into which the compressed air
from the wind turbines is preferably distributed and in which the compressed
air
energy can be stored and transported. Storage of compressed air energy allows
the
energy derived from the wind to be stored for a period of time until it is
needed. The
pipeline is also preferably used as a means of transporting the stored
compressed
air energy from the wind farm to the location where the energy is needed. The
wind
turbines and compressors are preferably located at one end of the pipeline,
and
turbo expanders, alternators and/or pneumatic equipment, etc., or other means
of
releasing and using the compressed air energy, are preferably located at the
opposite end of the pipeline, as shown in Figure 5, or along the length
thereof.
It can be seen that the wind turbines discussed above can be used to produce
compressed air energy directly for immediate delivery to the pipeline. It can
also be
seen that the compressed air energy can be stored in the pipeline to time
shift the
delivery of the energy, so that wind generated power can be made available at
a
remote location, even at times that are not coincident with when the wind
actually
blows, i.e., even when no wind is blowing, and/or during peak demand periods.
The
coordination and usage of these elements enables the current system to provide
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continuous and uninterrupted power to the end user in a stabilized manner,
despite
fluctuations and oscillations in wind speed, by coordinating and managing the
delivery of energy to the facility or community in need of the power.
The wind patterns in particular locations change from time to time, i.e., from
one season to another, from one month to another, and, most importantly, from
day
to day, hour to hour, and minute to minute. These fluctuations and
oscillations are
dealt with in conjunction with energy storage, by storing energy when it is
most
available, and then using the energy when it is most needed, such that the
system
can provide continuous output at a substantially constant rate, at a reduced
cost to
the utility. In this respect, the present invention contemplates operating a
wind farm
that uses high wind periods to cover low wind periods, and to smooth out the
delivery
of wind power. The long transmission pipeline permits the feed of a constant
power
output level to the end users during the daytime, thereby permitting the
utility to
charge more for power produced at night at a lower cost.
The system contemplates being able to monitor the amount of compressed air
energy inside the pipeline at any given time - it preferably measures the
amount of
pressure being compressed into storage, and the amount being released at any
given time, and the total amount of pressure inside. This way, the system can
keep
an adequate amount of pressure inside the pipeline, by controlling how much
energy
is supplied into the pipeline, and how much is being released. The controls
are
necessary to maintain proper pressure levels in the pipeline, in an effort to
make
sure that the system never runs out of compressed air energy, wherein the
pressure
is preferably maintained at a level of at least 200 psia.
The pipeline can be buried in the ground or located above ground and
extended between the wind turbine, and the communities and/or facilities where
the
energy is needed, which can be a distance of many miles. By storing energy in
this
fashion, the compressed air is preferably stored in and transported through
the
pipeline system along a planned route, as shown in Figures 1 and 2. This is
vastly
different from a standard transmission line which merely transmits energy,
i.e., when
the energy source is no longer able to provide power, no power will be
available
through the line. A benefit to using the present system is that the
transmission
means, i.e., the pipeline, has the ability to store energy. This way, unlike
conventional power lines, which can only transmit power, a predetermined
amount of
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energy can be stored, so that energy will be available, even if the energy
source
becomes temporarily unavailable, i.e., the wind stops blowing. In such case,
the
system will be able to continue to supply energy for a predetermined amount of
time
despite the lack of wind.
Another preferred aspect of the invention comprises using a planned route in
connection with installing the pipeline system to transport wind energy from a
remote
location where wind conditions are ideal to a location where energy is needed.
A
planned route is essentially a direct line or path extending from the energy
source to
the end user, i.e., facility or community. For example, in many cases, such a
path
preferably extends along or near an existing road, such as a service access
road,
that allows the pipeline to be installed along an already-cleared path, which
also
provides easier access to the wind farm. This also allows for easier
installation of
the pipeline, as well as easier access for repairs and service.
The selected path could also be routed along an existing easement, such as
along an existing underground conduit, such as an electrical or gas line,
sewer
pipes, etc., which can reduce the cost of installation. This is because it may
be
possible to use and/or rely upon the existing easements, land use permits,
right of
ways, environmental impact reports, etc., that were obtained to install the
existing
lines, which will allow the pipeline to be installed faster and at a lower
cost.
In cases where there is an abandoned existing underground pipe system,
such as a gas or sewer line, the present invention contemplates being able to
use
the abandoned pipe, in whole or in part, to help form the new pipeline system,
and
reduce the cost thereof. In this respect, if the existing pipeline is not the
correct size,
or does not extend the entire length, or is not entirely abandoned, the
present
invention contemplates using at least a portion of the existing pipe, i.e.,
whatever
portion can be utilized. The new pipeline can also be positioned adjacent to
the
existing pipeline, if necessary. All of the easements, land use permits and
environmental impact reports that were obtained for the existing pipeline can
be
used and/or relied upon for the new pipeline system.
In one embodiment, as schematically shown in Figure 4, the present invention
contemplates constructing the pipeline so that it is adjacent or connected to
an
existing railroad track, by positioning and connecting the pipeline directly
onto or
adjacent the railroad ties. The present invention contemplates taking
advantage of
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the easements and network of railroad tracks that have been constructed, which
often extend to remote locations from existing communities, to construct the
pipeline
at a reduced cost, and in a more efficient manner. The invention preferably
comprises using connectors to connect the pipeline to the railroad ties
themselves,
with the pipeline extending parallel to the tracks, so that maintenance work
can
easily be performed on the pipeline, by traveling along the tracks. This way,
the
pipeline will not need to be buried in the ground, so as to reduce the cost of
installation, and maintenance. The invention also contemplates that
intermittently
along the pipeline, certain exit points can be provided, wherein compressed
air can
be released to operate equipment, such as those that might be needed to repair
the
railroad track.
In another embodiment, also schematically shown in Figure 4, the present
invention contemplates constructing the pipeline along the desert floor,
exposed to
the hot sun, so that the pressure inside the pipeline can be advantageously
increased due to the heat. The exterior can be painted black, or other dark
color, to
enhance energy absorption. The thermal inertia of the wall thickness of the
pipeline
can provide a useful means of absorbing heat which can be used to increase
pressure inside the pipeline, and prevent the system from freezing during
expansion.
In this respect, it can be seen that there are advantages to locating the
pipeline
along the desert floor, such that the hot sun can help increase the pressure
inside
the pipe, wherein additional energy can be generated when released. The
present
invention contemplates that the pipeline, and/or related components, and their
masses, can be designed to absorb and release heat to maintain the stored
compressed air at a relatively stable temperature.
In certain cases, the total energy losses attributable to using a pipeline to
store and transport compressed air energy is less than the energy losses
attributable
to transmitting electricity through standard transmission lines, i.e., for the
same
distances. Accordingly, the present invention contemplates building a wind
turbine,
or wind farm, and instead of using standard transmission lines, using a
pipeline to
store and transport compressed air energy, wherein the losses inherent in
using
conventional transmission lines can be reduced. An analysis of the present
invention indicates that within certain distances, and circumstances, the
percentage
of energy losses experienced along the length of the pipeline can be less than
the
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percentage of losses attributed to standard transmission lines, and, in the
case of the
present invention, it has been found that the larger the pipeline, the greater
the
reduction in energy losses that can be experienced.
The present invention preferably takes into account the total percentage of
energy losses attributable to using a pipeline to store and transport
compressed air
energy, which has been found to be a function of several different factors,
including
the diameter of the pipeline, the pressure inside the pipeline, and the manner
in
which the compressed air is used, i.e., whether the compressed air is used to
generate electricity, or whether it is used to drive pneumatic equipment or
provide
cooling for an HVAC unit. The determination of the appropriate amount of
energy
storage capacity needed to operate the system efficiently preferably takes
into
account the desire to maintain a reduced percentage of energy losses along the
length of pipe, which preferably takes into account the friction that can
occur as
compressed air is released, as well as the other factors discussed herein.
One of the disadvantages of building a remotely located wind farm to transmit
electrical energy has been the cost of constructing the electrical
transmission lines,
and, its associated problems, including energy losses experienced along the
length
of the line. The invention contemplates determining the appropriate amount of
energy storage capacity needed to operate the system efficiently, and then
appropriating the proper amount of storage space within the pipeline to
accommodate the expected loads. As mentioned, it has been found that the
percentage rate of energy losses attributable to the pipeline can be reduced
by
increasing the diameter of the pipeline.
In this respect, as shown in Figure 11, it has been found that when larger
size
pipes, with greater volume, are used, the percentage of energy losses along
the
length of pipe, due to friction, can be reduced, i.e., the overall percentage
of energy
loss can be reduced by using a larger pipe. For example, according to Figure
11,
when a 100 mile long pipeline that is 3 feet in inside diameter is filled to
about 200
psia, a pressure drop of more than 20 psia can be expected by the time the
compressed air is released to drive the pneumatic equipment. On the other
hand,
when the same length pipeline is 4 feet in diameter, and is filled to the same
pressure, i.e., 200 psia, and is used for the same purpose, the pressure drop
that
can be expected is less than 10 psia. It can also be seen that when a 100 mile
long
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pipeline that is 3 feet in diameter is filled to about 600 psia, when used to
generate
electricity, a pressure drop of more than 60 psia can be expected by the time
the
compressed air is released at the opposite end of the pipeline. On the other
hand,
when the same length pipeline is 4 feet in diameter, and is filled to the same
pressure, i.e., 600 psia, and is used for the same purpose, the pressure drop
that
can be expected is less than 10 psia. Accordingly, it can be seen that the
amount of
pressure loss experienced along the length of the pipeline is at least partly
a function
of pipe diameter.
It has also been determined that there are greater pressure losses associated
with the use of turbo expanders to produce electricity, which require
relatively high
pressure, and greater air velocity, than associated with using the compressed
air to
drive pneumatic equipment, which doesn't require as much pressure or velocity
to
operate, i.e., they only need between 30 to 150 psig, on the average. For
example,
according to Figure 11, it can be seen that if the 3 feet diameter pipe is
filled to 200
psia, and is used to generate electricity, the pressure losses attributable to
friction
will be significant, i.e., the line representing that loss is off the charts,
making it
unsuited for that particular use. On the other hand, it can be seen that if
the same 3
feet diameter pipe is filled to the same 200 psia, but is used to drive
pneumatic
equipment, the pressure losses attributable to friction will only be a little
over 20 psia,
which is certainly manageable. This difference is primarily due to the fact
that
greater air velocity is needed, i.e., at least 200 psia (and preferably more),
to
generate electricity using a turbo expander, than is needed to drive pneumatic
equipment, i.e., only between 30 to 150 psia is needed. Accordingly, the
amount of
pressure drop in the pipeline is also a function of the type of energy usage,
i.e.,
whether for generating electricity or driving pneumatic equipment.
It has also been determined that there are greater pressure losses when there
is less pressure inside the pipeline at any given moment in time. For example,
according to Figure 11, it can be seen that if the 3 feet diameter pipe is
filled to a
pressure of 200 psia, and is used to drive pneumatic equipment, the pressure
losses
attributable to friction will be a little over 20 psia. On the other hand, it
can be seen
that if the same 3 feet diameter pipe has a pressure of 1,200 psia, for the
same
purpose, the pressure losses attributable to friction will be less than 5
psia. This
difference is primarily due to the fact that overall pressure can affect how
friction
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through the pipeline can be overcome. The more pressure there is in the
pipeline,
the more easily the friction can be overcome, whereas, the less pressure there
is in
the pipeline, the more difficult it is for the friction to be overcome.
Accordingiy, the
amount of pressure drop in the pipeline is also a function of air pressure in
the pipe.
Accordingly, it is desirable to provide a pipeline system having adequate size
and length, to maintain reasonable pressure levels and energy loss levels for
the
type of application the pipeline is being used for. The goal is to provide a
pipeline
size and length that will enable the system to run efficiently, with reduced
energy
losses along the length of the pipe, for all of the various applications and
end uses it
is being designed for. For example, a determination is preferably made to
determine
the approximate amount of storage volume or space that is to be used by the
system, followed by determining the length of the pipeline that will be laid,
as well as
the distance to and nature of the end user, and then determining the size
(diameter)
of the pipe needed to provide the appropriate amount of storage space for the
system. Additional calculations such as determining the power capacity levels
to be
supplied by the energy source, as well as pressure levels to be maintained in
the
pipeline, and expected pressure losses, can also be determined. This way, the
entire pipeline system can be designed for the specific loads that are
expected to
exist, without any further need for building additional pipelines, or any
extra storage
tanks, which can increase the cost thereof. This is unlike Tackett, U.S.
Patent No.
4,118,637, which shows a grid or network of pipes for storing energy, and
specifies
the largest possible commercially available pipe-size.
One variation of the pipeline that can be provided is to locate end users that
require production of electricity closer to the energy source, as shown in
Figures 6b
and 7b. In such case, it may be desirable to locate those users that need to
generate electricity closer to the source, so that less pressure loss will be
experienced along the length of the pipeline, by the time the compressed air
is
released by the turbo expander. Because pressure loss is a function of
friction along
the length of the pipe, which is affected by pipe diameter, type of energy
usage, and
amount of pressure, the pipeline itself can be designed so that, for example,
the first
25 miles of pipeline is 4 feet in diameter, to accommodate the higher
pressures
needed by the electricity users, and the remaining 75 miles of pipeline can be
made
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smaller, i.e., such as 3 feet in diameter, which should be sufficient to drive
pneumatic
equipment.
Even when using a consistent size pipe, i.e., 4 feet in inside diameter, when
multiple end users are tapped into the pipeline along the length of the
pipeline, and
the total length is considerable, i.e., 100 miles, it may be desirable to
locate the end
users that want to use turbo expanders to generate electricity closer to the
energy
source, i.e., within 25 miles of the source, rather than further down along
the length
of the pipeline. This is especially important if the pipeline diameter is only
3 feet,
instead of 4 feet, because, as shown in Figure 11, the pressure losses that
can be
experienced within the pipeline when the pressure begins to drop can be
significant.
And, in the case of using an energy source operated only during certain times
of the day, i.e., a utility that stores energy only during the nighttime, or a
wind farm
that only stores energy when the wind blows, there are likely to be lull
periods where
no additional compressed air energy is being added to the pipeline.
Accordingly,
there are likely to be times when the pressure inside the pipeline can get
fairly low, in
which case, the pressure losses can become significant. For the above reasons,
when a pipeline that is 3 feet in diameter or less is used, it is desirable to
locate the
end users that want to generate electricity using a turbo expander within 25
miles of
the energy source, whereas, when a 4 feet diameter pipeline is used, the end
user
wanting to generate electricity can be located further away, since, even when
pressure within the pipeline drops to below 600 psia, the pressure losses will
not be
as significant.
Notwithstanding the above, one preferred aspect of the present invention is
that the pipeline should be adapted so that additional end users can be tapped
into
the pipeline when the need arises in the future, i.e., as needs expand, as
shown in
Figure 8. That is, the pipeline should be pre-designed to accommodate multiple
end
users, then existing, as well as foreseeable future end users, with various
requirements, whether they need electricity, or air conditioning, or pneumatic
energy.
In this respect, it should be worth noting that the system should be designed
with the
expectation that the needs will be expanded in the future. One way to
accommodate
this expansion is to use a pipeline that is at least 4 feet in diameter, if
possible.
The amount of pressure in the pipe is preferably within the range of about 200
to 1,200 psig, wherein it is desirable to maintain the pressure at or above
600 psig, if
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possible, especially if the end user desires to use a turbo expander to
generate
electricity. When the end user only needs to use the compressed air for air
conditioning or to drive pneumatic equipment, the pressure can be lower, i.e.,
under
200 psia, although preferably, there is always at least 200 psia in the
pipeline.
The pressure losses should also be taken into account when determining how
long the compressed air energy, i.e., pressure within the pipeline, will last,
before
additional pressure will need to be added. This will determine the extent to
which a
greater capacity energy source, whether more wind turbines, or increased power
capacity of the utility, will be needed. It can also determine whether a
larger
diameter pipe, and/or a longer or shorter pipeline, should be used, and what
type
and location of end user should be allowed to tap into the pipeline to achieve
optimum results.
As shown in Figure 12, in the case of a source providing 10 MW of power,
such as a wind farm, using a 3 feet diameter pipeline, that is 100 miles long,
and
begins with a pressure of 1,200 psia, it has been found that the pipeline can
provide
up to about 32 hours of electrical power before more pressure would need to be
added to the pipeline. This means that if there is only one end user, the air
in the
pipeline might last a maximum of 32 hours, but if there are four end users, it
might
only last 8 hours. In this example, there is a total of 320 MW - hours of
energy
stored within the pipeline. There may also be additional volume stored in the
local
branches.
An important point to make here is that as the pressure begins to drop, due to
energy usage, and there is no additional energy being added back in, the
pressure
losses begin to become more significant, which is also more critical when the
pipeline is smaller in diameter. When the pipeline is larger, i.e., 4 feet in
diameter or
more, there is not only more volume of compressed air inside the pipeline, and
therefore, more energy in the pipeline, but the air in the pipeline will also
experience
a reduced amount of friction and pressure loss, as the compressed air is used,
as
discussed above.
The present invention also contemplates using additional wind turbine stations
with compressors or other means of intermittently supplying additional
pressure into
the pipeline, such as a connection to a grid, along the pipeline route, as
shown in
Figure 2. Preferably, to reduce cost, these wind turbines can have less
capacity
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than the main wind turbines. For example, the main wind turbines at the wind
farm
may have a total 10 MW rating, but the supporting wind turbines might have a 2
MW
rating. This way, additional pressure can be introduced into the pipeline, to
reduce
pressure losses, and provide a stable source of compressed air energy, that
can be
used continuously by the end user facilities and communities. Additional wind
turbines or wind farms, such as those located in other remote locations, which
are
connected to the pipeline, can also be used, as shown in Figure 2, to provide
additional compressed air energy into the system.
The present invention contemplates several different configurations for the
use of the compressed air energy stored in the pipeline, as shown in Figures
6a, 6b,
6c, 6d, 7a, 7b, 7c and 7d. Not only can multiple end users be connected to the
pipeline, to draw compressed air energy out, but each one can be located along
the
length of the pipeline, at various places along the pipeline, and can have
different
uses and applications. So long as the pipeline is sized and adapted to store a
sufficient amount of compressed air energy to accommodate the number, type and
nature of the end users tapping into the pipeline, and the amount of pressure,
and
losses attributable to each end user, are taken into account, there is no
limit to the
number and variety of end users that can be serviced by the pipeline.
Figure 6a shows an embodiment where a pipeline is used to service several
industrial parks outfitted with pneumatic equipment, wherein the pipeline is
100 miles
long, and 4 feet in inside diameter. In this example, the energy is produced
by a
geothermal, diesel or nuclear power plant, and an electric motor is used to
power a
compressor, which generates compressed air energy. Also, in this embodiment,
the
compressed air is preferably stored in the pipeline at night, so that it can
be used
during the day, to make more efficient use of the energy supplied by the
source. The
local branch pipelines can be 3 feet in diameter, since each one only services
a
single industrial park.
Figure 6b shows an embodiment where a pipeline is used to service several
industrial parks, each having a combination of pneumatic equipment, and
electricity
and air conditioning needs, wherein the pipeline is 100 miles long, and 4 feet
in
inside diameter. Again, in this embodiment, the energy is produced by a
geothermal,
diesel or nuclear power plant, and compressed air energy in the pipeline is
stored at
night, so that it can be used during the day. But in this embodiment, the
industrial
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parks that have electricity and air conditioning needs are preferably located
a
maximum of only about 25 miles away from the energy source, so that the
greater air
pressure requirements to service the turbo expanders can be satisfied. At the
same
time, the industrial parks that only need compressed air to drive pneumatic
equipment can be located further away, such as 100 miles away, since pneumatic
equipment requires less pressure and velocity to operate. The decision to
locate the
end user in this manner is based on the amount of pressure and energy losses
attributable to energy usage, as shown in Figure 11. In this case, the
remaining 75
miles of pipeline can be 3 feet in inside diameter, if desired, if the
pneumatic
equipment demands of the end users down stream can be met, despite the greater
pressure losses. The local branch pipelines can be 3 feet in diameter, since
each
one only services a single industrial park. The end user can install the turbo
generator to supply pneumatic, electric and air conditioning.
In another version, when more power is needed at the source, i.e., 40,000 kW
of power, rather than, say, 10,000 kW of transmitted power, it may be
desirable, in
view of the pressure losses that can occur along the length of the pipeline,
to use a
shorter pipeline, and increase the pipe size. For example, instead of using a
100
mile pipeline that is 4 feet in inside diameter, it may be more efficient to
reduce the
length of the pipeline down to say, 20 miles, and use two 4 feet diameter
pipes, so
that more energy can be stored, and more energy can reach the end user without
incurring too much energy loss. The resultant system preferably consists of
two 4-
feet diameter pipelines that are 20 miles long that can transmit 40,000 kW.
This
conclusion is based on how revenue is generated, which is based on power
usage,
and the need to recoup the cost of constructing the system, and the increased
pressure losses that can occur in the pipeline when trying to transmit more
compressed air energy at higher velocities to meet higher power demand. Note
that
this 20 mile system can be connected in series to meet a 100 mile system if
there
are other power sources along the route that could add energy to the pipeline
along
the way. Several booster stations can be provided to make up the pressure loss
that
can occur due to friction along the pipeline..
Figure 6c shows an embodiment where a pipeline is used to service several
industrial parks with air conditioning needs, wherein the pipeline is 100
miles long,
and 4 feet in inside diameter. Again, in this embodiment, the energy is
produced by
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a geothermal, diesel or nuclear power plant, and compressed air energy in the
pipeline is stored at night, so that it can be used during the day. The end
user can
install the turbo compressor and turbo expander to provide air conditioning.
The
local branch pipelines can be 3 feet in diameter, since each one only services
a
single industrial park.
Figure 6d shows an embodiment where a pipeline is used to service several
industrial parks with desalination facilities and air conditioning needs,
wherein the
pipeline is 100 miles long, and 4 feet in inside diameter. Again, in this
embodiment,
the energy is produced by a geothermal, diesel or nuclear power plant, and
compressed air energy in the pipeline is stored at night, so that it can be
used during
the day. The end user can install the turbo compressor, turbo expander, and
desalination system for its own industrial park. The local branch pipelines
can be 3
feet in diameter, since each one only services a single industrial park.
Figure 7a shows an embodiment where a pipeline is used to service several
industrial parks outftted with pneumatic equipment, wherein the pipeline is
100 miles
long, and 4 feet in inside diameter. In this embodiment, the energy is
produced by a
wind farm and energy from the wind is converted by a generator to drive an
electric
motor, which in turn, drives a compressor. The compressor then stores
compressed
air energy in the pipeline. The local branch pipelines can be 3 feet in
diameter, since
each one only services a single industrial park.
Figure 7b shows an embodiment where a pipeline is used to service several
industrial parks, each having a combination of pneumatic equipment, and the
need
for electricity and air conditioning, wherein the pipeline is 100 miles long,
and 4 feet
in inside diameter. Again, in this embodiment, the energy is produced by a
wind
farm, and energy from the wind is converted by a generator to drive an
electric
motor, which in turn, drives a compressor. The compressor then stores
compressed
air energy in the pipeline. But in this embodiment, the industrial parks that
have
electricity and air conditioning needs are preferably located a maximum of
only about
25 miles away from the wind farm, so that the greater air pressure
requirements to
service the turbo expanders can be satisfied. At the same time, the industrial
parks
that only need compressed air to drive pneumatic equipment can be located
further
away, such as 100 miles away, since pneumatic equipment requires less pressure
and velocity to operate. The decision to locate the end user in this manner is
based
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on the amount of pressure and energy losses attributable to energy usage, as
shown
in Figure 11. In this case, the remaining 75 miles of pipeline can be smaller,
such as
3 feet in inside diameter, if the pneumatic equipment demands of the end users
down stream can be met, despite the greater pressure losses. The local branch
pipelines can be 3 feet in diameter, since each one only services a single
industrial
park. The end user can install the turbo generator to supply pneumatic,
electric and
air conditioning.
Figure 7c shows an embodiment where a pipeline is used to service several
industrial parks with air conditioning needs, wherein the pipeline is 100
miles long,
and 4 feet in inside diameter. Again, in this embodiment, the energy is
produced by
a wind farm, and energy from the wind is converted by a generator to drive an
electric motor, which in turn, drives a compressor. The compressor then stores
compressed air energy in the pipeline. The end user can install the turbo
compressor and turbo expander to provide air conditioning. The local branch
pipelines can be 3 feet in diameter, since each one only services a single
industrial
park.
Figure 7d shows an embodiment where a pipeline is used to service several
industrial parks with desalination facilities and air conditioning needs,
wherein the
pipeline is 100 miles long, and 4 feet in inside diameter. Again, in this
embodiment,
the energy is produced by a wind farm, and energy from the wind is converted
by a
generator to drive an electric motor, which in turn, drives a compressor. The
compressor then stores compressed air energy in the pipeline. The end user
installs
the turbo compressor, turbo expander, and desalination system for its own
industrial
park. The local branch pipelines can be 3 feet in diameter, since each one
only
services a single industrial park.
Various embodiments with different configurations are contemplated.
1. The First Configuration:
In one embodiment, the present invention uses the waste chilled air by-
product generated as electricity is being produced by releasing compressed air
energy with the turbo expander to operate an HVAC unit for air conditioning,
or for
refrigeration, or both. Means for releasing the compressed air, such as turbo
expanders, to enable the compressed air to be released and expanded are
preferably provided. This way, the stored compressed air energy in the
pipeline can
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be used to drive an electric generator, to generate electrical power on an "as
needed" basis. And while releasing the compressed air energy generates
electricity,
the system can co-generate chilled air, which is a waste by-product of
releasing the
compressed air.
The chilled air can be re-cycled and used directly, i.e., in the form of
chilled
air, which can be mixed with the ambient air, or fed into an HVAC unit, to
keep the
end user facilities cool. While the input air in the pipeline begins at an
ambient
temperature of about 70 degrees F., the resultant chilled air produced as a by-
product of producing electricity can be as cold as minus 170 degrees F. or
more.
Moreover, at the same time, the system preferably converts compressed air
energy
into electricity, which can be used for lighting, heating, cooling, and other
conventional utilities. For example, if electricity is needed at the end user
facility, a
turbo expander and. generator can be connected to the pipeline, such that the
compressed air can be released to generate electrical energy, and to co-
generate
chilled air, wherein the total efficiency of the facility can be improved.
This way, the
entire system can be constructed and used in a manner that makes the facility
more
efficient to operate, than would be the case when using standard electrical
systems
alone.
In this respect, in this embodiment, preferably, no heat source is provided,
or
if it is, it should be turned off, as shown in Figure 5, so that greater
chilled air is
produced, which allows the system to take full advantage of the waste chilled
air
generated as the compressed air is released. Not only is electricity
generated, but
the system preferably produces maximum chilled air, which can be used not only
for
refrigeration and air conditioning purposes, but also for desalination.
The desalination systems that are contemplated to be used in conjunction
with the present invention are those that utilize chilled air to freeze water,
which
effectively helps separate the contaminants found in seawater and other
brackish
water from the water, thereby producing fresh drinking water. In areas where
fresh
drinking water is scarce, the chilled air being generated by releasing the
compressed
air can be used to desalinate water. The chilled air can be fed into a freeze
crystallization chamber, where seawater is sprayed, to produce ice, and
therefore,
desalinate water. A thermal energy storage system can also be used to store
the
chilled water generated by the chilled air in a supplemental storage unit for
later use.
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These embodiments are especially suited for warm weather climates, such as in
deserts, where access to fresh drinking water may be difficult to achieve.
Another version of this embodiment can be adapted to provide only chilled air,
and no electricity, by using a turbo expander that releases the compressed air
energy to generate chilled air to cool the facility. This situation can occur
when a
facility is already connected to the power grid, and can obtain electrical
power from
the grid, i.e., for its other functions, but wants a low cost way to provide
cooling for
the facility. In such case, the facility can purchase its own turbo expander,
and
connect a branch pipeline to the main pipeline, and tap into the compressed
air
energy, to generate chilled air.
A possible configuration for this version is shown in Figure 9, wherein a
turbo
compressor uses the compressed air from the pipeline to pressurize a surge
tank,
which helps to smooth out the deliver of power. Then, as the turbo compressor
rotates because of the input pressure, it causes the turbo expander to rotate.
The
surge tank continues to pressurize and the turbo expander continues to
accelerate
until there is a steady-state pressure inside the surge tank that is higher
than the
input pressure. Accordingly, there is a continuous conversion of the input
air, to
create an output air, which is at a reduced temperature, and ambient pressure.
For
example, the input pressure can be 90 psia, which can be increased to 200 psia
in
the surge tank, and the resultant output temperature can be in the order of
minus 70
to minus 170 degrees F., with the output pressure being 14.67 psia (0 psig).
In a variation of the embodiment, the utility can pay for the pipeline and the
individual end users can pay for the equipment to extract and use the
compressed
air energy stored in the pipeline, such as turbo expanders, HVAC units,
desalination
systems, etc. In such case, the utility can install the pipeline and achieve
payback
on the investment in a reasonable time, and the end user can purchase its own
equipment that would have its own payback period.
2. The Second Configuration:
In a second embodiment, heating is preferably provided on a limited basis.
For example, in this embodiment, only an existing heat source is preferably
used,
such as the waste heat generated by the compressors as the air is compressed,
which can be stored in the pipeline. Additional heat from the sun, by locating
the
pipeline above ground, on the desert floor, can also be used. This way, there
is a
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higher efficiency of delivery of electrical power, even though at the expense
of less
chilled air. In this embodiment, however, an effort is made to eliminate using
any
additional energy source to provide heat, which would require its own power
source
to operate.
This embodiment has the advantage of being able to generate, in addition to
electrical power, a certain amount of chilled air. This embodiment preferably
takes
advantage of the chilled air being generated by the turbo expander, i.e., as
the
compressed air is released, to provide chilled air for cooling purposes. For
example,
the waste chilled air from the turbo expander can be used for refrigeration
and air
conditioning purposes, which is especially helpful when the community or
facility that
the pipeline services is located in a warm climate. When the waste heat is
used, the
system contemplates being able to heat the compressed air in the pipeline from
normal ambient temperature of about 70 degrees F., as in the first embodiment,
to a
temperature of about 250 degrees F., wherein the chilled air that is co-
generated can
then be increased in temperature to about minus 75 degrees F.
3. The Third Configuration:
In a third embodiment, the system is advantageously provided with several
heaters to enhance the generation of electricity from the compressed air. For
example, waste heat from the compressors, or other heat sources, can be
provided,
as the compressed air is released, to maximize the generation of electricity
thereby.
For example, this embodiment contemplates using at least one of three
different
types of heating systems, including 1) solar thermal collectors that utilize
energy
from the sun, including locating the pipeline above ground, to make efficient
use of
the sun's heat, 2) waste heat collectors to circulate the waste heat generated
by the
compressor to the compressed air in the pipeline, and 3) a separate heating
unit,
such as a fossil fuel burner, to introduce heat into the pipeline, or add heat
to the
turbo expander input as compressed air is being released by the turbo
expander.
The invention also contemplates using other standard methods of providing heat
to
the compressed air, such as combustors, etc., if desired. When these heaters
are
used, the system contemplates being able to heat the compressed air from the
250
degrees F. achieved by the waste heat alone, to about 490 degrees F., wherein
the
resultant air delivered after the compressed air is released can be a
comfortable plus
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70 degrees F. With this embodiment, there is an even higher efficiency
delivery of
electrical power, but at the complete expense of no chilled air.
The increased temperature provides several advantages. First, it has been
found that heat contributes greatly to the efficiency of overall work
performed by the
turbo expanders, and therefore, by increasing the temperature of the
compressed
air, a greater amount of energy can be generated from the same size storage
volume. Second, by increasing the temperature of the air, the pressure can be
increased, wherein a greater velocity can be generated through the turbo
expander.
Third, heating the air helps to avoid freezing that can otherwise be caused by
the
expansion of the air by the turbo expander. Without any heat source, the
temperature of the air being released can reach near cryogenic levels, wherein
water
vapor and carbon dioxide gas can freeze and reduce the efficiency of the
system.
This embodiriment is preferably able to maintain the temperature of the
expanding air
at an acceptable level, to help maintain the operating efficiency of the
system.
According to Figure 10, when using a turbo expander, it can be seen that the
greater
the input temperature, the greater the output temperature, whereas power
efficiency
decreases.
4. The Fourth Configuration:
In a fourth embodiment, the compressed air is delivered by the pipeline to an
industrial park, or other industrial facility, and the compressed air is used
directly at
the park or facility, to operate pneumatic equipment. This can be done, either
in
addition to, or instead of, producing electrical energy, and co-generating
chilled air.
When the facility is not hooked up to the grid, the facility can be adapted to
produce
electricity with the turbo expander and use the compressed air to drive
pneumatic
equipment at the same time, thereby enhancing the efficiency and economics of
the
system, and alleviating excess loads on the grid. The turbo expander can also
be
used to produce chilled air as a by-product, in which case, it can be used for
air
conditioning and other cooling purposes. In most cases, an industrial facility
will
require both pneumatic power and electrical power, i.e., pneumatic power to
operate
its heavy equipment and tools, and electricity for other functions. Chilled
air can also
be used as a bi-product of releasing the air. On the other hand, when the
facility is
hooked up to the grid, the facility can be adapted to draw only pneumatic
power. In
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such case, the compressed air energy can be used to supplement the electrical
energy already available at the site.
To take maximum advantage of the pneumatic power supplied to a given
facility, the facility that uses the compressed air energy should be one that
normally
uses pneumatically driven equipment in its daily operations. When compressed
air
is utilized to operate pneumatic equipment, without having to convert the
compressed air energy into electricity first, the efficiencies of the system
are
improved. While there may be a certain amount of power loss that occurs over
the
length of the pipeline, i.e., due to friction as discussed above, since the
compressed
air is used without having to convert the energy into electricity first, there
are no
other losses associated with converting compressed air energy into electrical
energy.
Thus, the inefficiencies associated with the conversion of pneumatic power to
electric power can be eliminated.
In this aspect, the present invention relates to an improved method of storing
energy in the form of compressed air, via a pipeline, and then transporting
the
compressed air, via the same pipeline, to a facility that operates
pneumatically driven
equipment, such that the compressed air can be utilized to operate the
equipment
without having to convert the compressed air energy into electricity first.
Unlike past
wind farms, and past compressed air systems, which require compressed air
energy
to be converted into electricity first, the present invention can utilize a
pipeline
system for storing the compressed air energy, and transporting it to a
location where
it can be used, without having to convert the compressed air energy into
electricity
first.
There are also significant operational and economic advantages to using
pneumatic systems. For example, pneumatic tools have less friction, so they
tend to
last longer than conventional mechanical tools. Also, when they are kept clean
and
lubricated, they can be almost indestructible. They have very few moving
parts, and
they normally run cool. Some of the pneumatic equipment contemplated by the
present invention include the following: Blow guns; nail guns; air staplers;
air
sanders; spray guns; sandblasters; caulking guns; air ratchet wrenches; air
hammers; air chisels; air drills; impact wrenches; die grinders; cut off
tools; tire
buffers; air reciprocating saws; air nibblers; air flange tools; air
screwdrivers; air
shears; air polishers, etc. A series of control valves that produce varying
degrees of
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pressure, such as 50 psig, 100 psig, and 150 psig, to drive the pneumatic
equipment, can be provided.
5. The Fifth Configuration:
In a fifth embodiment, a utility plant, such as conventional fuel combustion-
driven turbine generators, geothermal, nuclear, hydroelectric, etc., or a
grid, can be
connected to the pipeline, in addition to, or instead of, incorporating a wind
farm to
produce the energy. In this respect, consider that a nuclear power plant is
desirably
located far enough away from population centers for safety reasons, i.e., in
case of a
potential radioactive cloud release, and therefore, using the pipeline of the
present
invention can be helpful in being able to locate the utility far enough away
from the
community or facility in need of the power.
In this embodiment, the pipeline system can be connected to an existing
power source, such as a utility or grid, wherein the system can be designed to
compress air and store energy during low demand periods, such as at night, and
use
the stored energy during high demand periods, such as during the day. This
way,
the utility can continue to operate at its most efficient levels, and can
store the
energy that is produced when the demand is low, to supplement the energy that
is
needed during the high demand periods. This not only helps to reduce the cost
of
energy, from the standpoint of energy production, but also helps the energy
user.
Using this system, utilities are able to provide more energy during the high
demand periods, without necessarily having to construct a higher capacity
power
generation facility, which would be more costly to do, to account for the
higher
demands. The energy that is produced can be stored in the pipeline at night,
and
transported to the end user via the pipeline, rather than a standard
transmission line,
and used during the day. This takes into consideration that the utility
operates most
effectively at constant load, while facing a constant demand power history.
The
problem the invention overcomes is that typical power plants face a diurnal
variable
demand power history, wherein the pneumatic transmission pipeline takes a
variable
diurnal demand power history and converts it to a constant demand power
history.
Conventional fuel combustion-driven turbine generator, geothermal and nuclear
power plants prefer to operate at the same power level, day and night. Varying
power level operation tends to fatigue the high speed rotational parts during
their
windup periods. The transfer pipeline permits these variations in power levels
to be
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eliminated. Also, utilities are able to produce energy at consistently high
levels, and
at constant power output levels, which maximizes the efficiency of the
facility.
Further, the utility is able to charge more for the energy used during the
high demand
periods, even though the energy is actually produced during the low demand,
low
cost, periods, i.e., nighttime power is sold at daytime rates.
From the standpoint of the user, the energy rates during the high demand
periods can be made lower, and there are fewer risks associated with surges,
spikes
and outages occurring.
6. The Sixth Configuration:
In a sixth embodiment, one or more of the features described above in
connection with the first five configurations can be incorporated into a
single system,
and can be used to provide energy to multiple communities and facilities along
the
length of the pipeline. Each of the communities or facilities can tap into the
main
pipeline using a local branch pipeline connected thereto, i.e., for example,
the main
pipeline can be 100 miles long, and each branch can be 5 miles long. Each
branch
can also provide additional volume for compressed air energy storage.
As an example of a combination system, the pipeline can be located in a hot
desert, and be used to service a facility that uses electricity and pneumatic
energy.
In such case, the system is preferably installed without a heating element, or
with the
heating element turned off, so that the system can co-generate electricity and
maximum chilled air at the same time. The system can also be set up so that
some
of the compressed air energy can drive the pneumatic equipment, thereby
increasing
the overall efficiencies of the system. Likewise, the system can be adapted so
that
compressed air energy can be generated by both a wind farm and a utility, to
account for the uncertainties associated with using wind as a power source. It
is
sometimes advantageous to provide a secondary source of energy, such as a
utility,
or grid, which can be accessed when little or no wind is available.
Preferably, a series of servo check valves, gages and control logic are
provided along the pipeline, so that the amount and rate at which the
compressed air
is stored and released at each end user station can be controlled and
monitored. In
this respect, to properly apportion the amount of energy being supplied using
the
present system, it is necessary to know how much compressed air energy is
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available, by determining how much pressure is actually in the pipeline at any
given
time, and then being able to release it at the appropriate rate.
The peesent invention preferably comprises sufficient storage capacity to
enable sufficient power to be stored and released, even when the wind stops
blowing
for more than a week at a time. This is accomplished by anticipating the wind
conditions and characteristics, and then using that data to effectively plan
and
develop a schedule, with the objective of enabling the system to compress the
maximum amount of energy into storage when wind energy output levels are
relatively high. By being able to store the compressed air energy, and
releasing the
energy at the appropriate time, in the manner described above, the present
system
is preferably able to effectively coordinate, manage and stabilize the
delivery of
energy in a manner that enables wind power fluctuations and oscillations to be
reduced or avoided. This enables the system to stabilize and smooth the
delivery of
power, and avoid sudden surges and swings, which can adversely affect the
power
delivery system.
37
