Water usage and nuclear power plants April 23, 2010
Posted by cleanidahoenergy in
nuclear industry,
Water policy.
Water usage and nuclear power plants is little known in the U.S.,
even in areas where water is at a premium such as in the semi-arid
western states, where most of the fresh water is consumed in this
country. Here are the facts:
- About 80% is used for irrigation and much of that is for golf
courses, lawns, parks, recreation fields, swimming pools and
commercial property beautification. 2 billion gallons per day is
used on golf courses alone.
- Approximately 10% is used for industry and business.
- About 7% is used for household use including some irrigation.
- The remainder, around 3.0% is used for thermal power plants.
Nuclear, coal, combined cycle gas, CSP solar and geothermal are
thermal plants. Coal plants are by far the largest user, followed
by nuclear plants, and finally combined cycle gas plants in order of
power production.
Figures from the above graph are very similar for Idaho except only
about .01% of the fresh water is used for thermal power plants.
Note:
It is critical to point out just how much water leaves southern Idaho on
an annual basis without ever being used. In fact, 7,900,000 acre
feet of water leaves the state every year via the Snake River, which has
the Payette River as one of its tributaries.
A proposed nuclear power plant in Payette County would use
less than 1% of this water.
(Source: SPF Water Engineering)
What sources of electricity require the most water?
- There are 2400 hydroelectric plants in the United States that
require the largest amount of water than any other power producer.
However, hydro plants only produce 7% of the nation’s electricity
and around 40% in Idaho, which is decreasing according to the Athena
report. (http://www.harvestcleanenergy.org/IdahoEnergy/IdahoEnergyFuture_PR.pdf)
While there is some evaporation behind the dams, much of the water
is held for production of often small amounts of power instead of
flood control even when the water is needed in semi-arid climates
for crop irrigation and industry. There are no emissions with
hydro, however, these plants negatively impact the environment in a
variety of ways including fish passage and silting.
- There are 600 coal plants in the U.S., which require more water
than any other thermal power source due to the large number of
units. Coal produces 50% of the nation’s electricity, but they have
the worst emissions of all power sources. Many of these emissions
contain mercury, sulfur and CO2.
- There are 104 nuclear plants in the U.S. which use less water
with fewer units than coal. Nuclear power plants produce 20% of the
nation’s electricity and 70% of all emission-free electricity.
- Combine-cycle gas plants use the least amount of water of all
the major power sources because they are the smallest power
contributor. However, these plants are rapidly growing in number
and emit a large amount of CO2, although those emissions
are about half the amount of an equivalent size coal plant.
- Geothermal plants produce less than 1% of the nation’s power and
use water much like any equivalent size thermal plant. However,
many of these plants have to inject water into the earth, which
requires even more of this valuable resource.
- Solar power plants, while contributing less than 1% of our
electricity, use more water than thermal plants to wash the panels
and for cooling of Concentrated Solar Power (CSP).
- Almost all thermal power plants require about the same amount of
water to cool a megawatt using conventional cooling methods.
Nuclear plant water usage:
There is a great deal of misinformation surrounding nuclear plant
water usage often propagated by opponents of nuclear power. Water is
recirculated for cooling of the power plant and it is consumed by the
plant as well. Here’s a look at the facts:
- The power block in a steam-cycle plant, which actually produces
the power, will consume between 50,000 to 100,000 gallons per day
depending on the design and operations.
- The workers at the plant will consume 500,000 to 700,000 gallons
for day for toilets, cooking, washing and other general industrial
usage.
- AEHI’s design will use a hybrid cooling system that will control
consumption depending on water availability to less than one million
gallons per day or 1000 acre-feet per year (140 acres irrigated) for
the steam cycle and plant usage (listed above) if required due to
water shortage. This minimum consumptive mode is known as dry
cooling.
- Depending on the reactor’s total power and the cooling system
design, the plant can recirculate up to 20 to 25 million gallons per
day for cooling. In this cooling system, water is pumped from the
water source (river) to fill ponds near the power plant. It is then
circulated from one pond into the plant for cooling, afterwards the
water is returned to another pond to cool before being sent back to
the first pond to use again. These ponds will be filled when water
flow in the river is high.
- Many older nuclear plants use high water consumptive cooling up
to 90% of the recirculated water (such as cooling towers which are
spray evaporative cooling) and were built where water was abundant
from large rivers and lakes at these locations.
Source: 2005 USGS data (most recent available data)
Conclusion:
The U.S. has water for almost every use including irrigating lawns,
golf courses and ball parks while using the least amount of water to
produce arguably one of our most important products for the success of
our economy — reliable baseload electricity.
In most of Idaho, as in the rest of the U.S., without electricity,
the economy would be devastated. So, it would seem water for power
production should be a very high priority especially given the amount of
electricity returned from large thermal plants. Specifically, less than
1% of the water leaving Idaho would cool a large dual unit nuclear power
plant producing enough reliable power to address all foreseeable growth
while stabilizing increasing power costs.
Comment:
This article was very informative. I was among those that believed
water consumption to cool a reactor was considerably higher. This
information gives me a good deal more peace of mind about this aspect of
nuclear energy, but I also consider the disposal of nuclear waste to be
a really, frightening factor. What is the current policy concerning
disposal of the radioactive waste?
http://cleanidahoenergy.wordpress.com/2010/04/23/water-usage-and-nuclear-power-plants/
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