Note: The following is a paper I've prepared for my Masters in Infrastructure Planning and Management at the University of Washington, Seattle. I think you may find this interesting in light of today's concerns about water for thermal power plants.
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Background
I have been associated with electricity generation in one
form or other as part of my profession since 1974. I have operated nuclear power plants and been
associated with hydroelectric generation, combustion turbine generation,
coal-fired generation and even wind/solar and distributed generation such as
diesel generators. During this time I've
learned that water is a very critical and foundational service for the thermal
plants in particular. Unfortunately as
time progresses we are witnessing more issues relative to reduced availability
and quantity of water for these plants.
Additionally there are challenges with climate change causing the water
temperatures to rise and thus make it more difficult to efficiently generate
power at some nuclear and coal-fired plants.
Key Aspects of Water and Electricity Generation
As noted above the key aspects of water supply and thermal
energy generation is the quantity used and the maximum temperature permitted
for plant operation. In the table below, you can see that water use for thermal/non-hydro
generation can be substantial:
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| http://www.westernresourceadvocates.org/water/waterenergy.php |
Not only is a substantial quantity of water required for
electricity generation but you should also consider that the discharge from the
plant could contribute to increasing the temperature of the regional water
supply which has impacts on fisheries, algae blooms, etc.
For some added statistics, the amount of water the nation's 19,000 power generating units consume
is approximately 100 billion gallons a day -- three times what cascades over
Niagara Falls in the same time frame. (Spiegel 2012)
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| http://www.ctmirror.org/story/2012/09/19/millstone-shutdown-sign-broader-power-problem-caused-climate-change |
Case Examples
Some case examples where water quantity/volume and
temperature have played key roles in the ability of the plants to generate or
not are as follows:
Millstone Nuclear Plant, Connecticut, 2012
In
August 2012 the Millstone Nuclear Power Station near New London, Connecticut,
was shut down for 12 days because the seawater used to cool the plant’s Unit 2
generating plant became too warm. It was
the first time any US nuclear plant was shut down because of intake water
thermal limits. The source of the
cooling water is Long Island Sound. Of note and since 1975 when the plant
started up, plant scientists have noted that Long Island Sound’s temperature
rise about 0.7 degrees F a decade for about 2.8 degrees total. This increase is attributed to ocean
temperature rise due to climate change. (Spiegel 2012)
Browns Ferry Nuclear Plant, Alabama, 2011
The Browns Ferry Nuclear Plant in Alabama had to shut down
more than once the summer of 2011
because the Tennessee River's water was too warm to use it for cooling. (Koch 2012)
One North Texas power plant (name unknown) had to reduce its
generation output because the water level in its cooling reservoir had fallen
substantially. (Fowler 2011)
Corette Power Plant, Montana, 2001
The 160-megawatt Corette Power Plant, located along the Yellowstone
River in Billings, Montana, depends on a
once-through cooling system, diverting 54-million gallons of water from the
Yellowstone River each day. The plant’s water intake pumps work only if the
river flow stays above 1,500 cubic feet per second. In recent years, this
threshold was not met for several days at a time, forcing the plant to shut
down. In this case water flow rates
affect the ability of the plant to operate or not. (Clean Air
Task Force 2003)
Some Conclusions
According to a
study commissioned by the European Commission and entitled “Vulnerability of US
and European Electricity Supply to Climate Change,” projects that the next 50
years of warmer water and lower water flows will lead to more power generation
disruptions. The authors project that
thermoelectric power generating capacity from 2031 to 2060 will drop by 4 and
16 percent in the US and 6 and 19 percent in Europe due to lack of cooling
water. They also go on to note that the
likelihood of extreme drops in power generation – complete or total shutdowns –
is projected to almost triple. (van Vliet, et al. 2012)
This report goes on
to note that reduced water availability and warmer water – caused by increasing
air temperature associated with climate change – will result in higher
electricity costs and reduced reliability.
Those plants that rely on once-through cooing are the most vulnerable
versus those that recycle their cooing water via cooling towers.
Discharging water
at elevated temperatures causes yet another problem: downstream thermal
pollution which can affect life cycles of affected aquatic flora and
fauna. Also, this higher temperature
could be an added impact on downstream power generation using the same water
for cooling.
Overall, this appears to be a very interesting area to pursue further
research and review of the current issues with water, electricity generation
and climate change.
Bibliography
Clean Air Task Force. "The Last Straw: Water
Use by Power Plants in the Arid West." The Last Straw: Water Use by
Power Plants in the Arid West. April 2003.
http://www.westernresourceadvocates.org/media/pdf/laststraw2009.pdf (accessed
January 12, 2014).
Fowler, Tom. More power plant woes likely if
Texas drought drags into winter. August 24, 2011.
http://fuelfix.com/blog/2011/08/24/more-power-plant-woes-likely-if-texas-drought-drags-into-winter/
(accessed January 12, 2014).
Hickey, Hanna. Nuclear and coal-fired electrical
plants vulnerable to climate change. June 3, 2012.
http://www.eurekalert.org/pub_releases/2012-06/uow-nac053112.php (accessed
January 12, 2014).
Koch, Wendy. Climate change causes nuclear, coal
plant shutdowns. June 5, 2012. http://content.usatoday.com/communities/greenhouse/post/2012/06/climate-change-makes-nuclear-coal-power-plants-vulnerable/1#.UtLevfRDua8
(accessed January 12, 2014).
Spiegel, Jan Ellen. Millstone shutdown is a sign
of broader power problem caused by climate change. September 24, 2012.
http://www.ctmirror.org/story/2012/09/19/millstone-shutdown-sign-broader-power-problem-caused-climate-change
(accessed January 12, 2014).
van Vliet, Michelle T. H., John R. Yearsley, Fulco
Ludwig, Stefan Vögele, Dennis P. Lettenmaier, and Pavel Kabat.
"Vulnerability of US and European electricity supply to climate
change." Nature Climate Change (Macmillan Publishers Limited),
June 2012: 1-6.
Western Resource Advocates. Water Use for Energy.
n.d. http://www.westernresourceadvocates.org/water/waterenergy.php (accessed
January 12, 2014).
