Water and power have
been synonymous with each other since the early days of the
industrial revolution. The energy of water drove waterwheels that
provided the power used by mills and by factories. When the steam
age dawned, water was boiled to drive steam engines that powered
the economy. At the present day, water and power are still
synonymous with each other in modern hydroelectric dams and in
coal-fired and in nuclear power stations.
Power generation is affected by climate and the onset of
climate change has reduced rainfall in many regions of continental
North America. By 2004, successive years of low rainfall in the
watershed area of Quebec's James Bay hydroelectric project reduced
water levels to near critical in the holding dams. The
Southwestern United States has also undergone several success
years of low rainfall. Long-term weather patterns have indicated
that the earth has undergone several periods of low rainfall
during its past history. During those periods, the human
population was a fraction of what it is at the present day.
The human population has steadily increased since the last
periods of reduced rainfall and has become highly urbanized in
most regions of the world. This population requires a steady
supply of electrical energy as well as clean water for its
personal and economic survival. During the 1950's by an engineer
named Garrison recognized that America had a future need for an
expanded secure supply of fresh water. He became aware that most
of the rainfall that fell over Canada collected into rivers that
flowed toward the Arctic and into Hudson Bay and devised a plan
that became known as the Garrison diversion. The plan proposed to
divert fresh water from Northern Canada by pipeline into heavily
populated areas of the USA.
Today, several large hydroelectric dams that supply power to
parts of Canada as well as to the north central and northeastern
USA are located on some of these very rivers. Garrison's diversion
scheme would require that several Canadian hydroelectric dams be
closed in order for water to be diverted to southern destinations.
New thermal power stations would need to be built to replace the
hydroelectric installations as well as to provide energy to pump
water against gravity to enable it to flow south to American
destinations. Additional energy would be needed during cold
northern winters to prevent water from freezing in the pipeline
system. The system could cost well in excess of $100-billion to
construct and several million dollars per year more to operate.
The American power industry may be able to offer several more
cost-effective alternatives whereby several American coastal
cities may gain access to a supply of fresh water for human
consumption. Some of the technology was developed for use in the
Middle East where very little fresh water occurs naturally and
where a growing population has a growing need for fresh water.
Heat rejected from thermal power stations has been used to
desalinate ocean water in hot and arid regions. Several thermal
power stations are located near the coast in several American
states and the reject heat can be used for this purpose. During
winter, snow falling in the northern states usually ensures an
adequate supply of water for the human population.
During the hot summer months, large cities like New York City,
Chicago, Los Angeles and several other southwestern cities face
constrained water supplies and water restrictions. The City of
Santa Barbara in southern California reduced fresh water
consumption by installing a duplicate municipal plumbing system
that enabled toilets to be flushed using ocean water. This
pioneering conversion could be undertaken in numerous other
coastal cities and it may take decades for major cities the size
of Los Angeles to install new independent plumbing systems by
which to operate the sewer systems. It is likely that the total
overall cost of installing such systems in America's major coastal
cities may be less than constructing and operating a modernized
version of the Garrison diversion scheme.
An initiative to introduce duplicate plumbing systems into
coastal cities could coincide with initiatives to make large
cities more energy efficient when it comes to heating or cooling
large numbers of large buildings. During summer, cool water from
the ocean may serve as a heat sink and reduce the amount of energy
that large skyscrapers use for air conditioning. The City of
Toronto in Canada recently introduced a central cooling system for
the central business district where cold water from the bottom of
Lake Ontario is used to cool an entire district of large
skyscrapers. A similar result may be achieved if exhaust steam
from a nearby steam-thermal power station is used to drive vacuum
refrigeration technology, a large-scale technology uses water as a
refrigerant and can cool it to as low as 5-degrees C (41-degrees
F).
A 1,000-Mw coal fired or nuclear steam power station may
operate at an efficiency of 40% will reject the equivalent of
1,500-Mw in heat. During winter, this heat may be used for
district heating within a radius of up to 40-miles from the power
station. During summer, the heat rejected in the exhaust steam may
be divided between energizing water desalination technology and
driving steam vacuum refrigeration equipment that can typically
operate with a coefficient of performance (C.O.P) approaching
unity. The cooled water would be pumped through the same piping
systems that carry warm water during winter for the purpose of
district heating.
Natural gas fired power stations that operate in the Middle
East use gas turbine engines of up to 380-Mw each. These engines
are often equipped with heat exchangers that are located
downstream of the exhaust systems and for the purpose of using
engine exhaust heat to operate ocean water desalination equipment.
The amount of heat in the exhaust is also sufficient to provide
district heating during winter or to raise steam at low pressure
that may drive steam vacuum refrigeration systems during summer.
Water vapor is also a major component of the combustion gases of
gas turbine engines that operate on natural gas. These gases (CO2
and H2O) are free from engine lubrication contaminants and the
vapor may be condensed via heat exchanger using ocean water as a
heat sink. The water would likely be pure enough for human
consumption.
America's Southwest and Midwest has growing need for fresh
water during summer while the Mississippi River usually overflows
its banks every spring. The Red River flowing from North Dakota
into Manitoba overflows its banks there almost every spring. At
the same time, water levels in Lakes Superior, Michigan and Huron
have been steadily dropping for several years. Lakes Superior and
Michigan may have enough storage capacity to contain excess spring
water pumped in from the Mississippi and Red Rivers. To hold extra
water in Lake Michigan, a control dam would need to be built at
the Strait of Mackinac. Shipping locks that can operate as control
dams already exist at the exit of Lake Superior.
The river water would be pumped into the big lakes at a time of
year when the demand for energy to provide winter heating is in
decline across North America. Extra electrical generation capacity
may be available during spring when no air conditioners would be
operating. During off-peak periods for power stations during
spring, the added electrical power would be used to drive water
pumps. As America's demand for fresh water increases, the power
industry would come to play a more significant role in providing
fresh water. The combination of pumping fresh water into storage
at northern latitudes, desalinating ocean water from the exhaust
heat of power stations, condensing the exhaust of natural gas
powered gas turbine engines and using ocean water to flush the
bathrooms would all contribute to helping meet America's need for
water. The power industry has the potential to become an integral
part of the solution in this regard.
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