Most of the electricity generated around the world is produced using water
intensive processes. Thermoelectric power plants use fossil and nuclear
fuels to heat water in large boilers where steam is created to drive large
turbine generators. Water is circulated throughout the power plants in
huge quantities to cool the turbines, clean scrubbers and boilers, and
perform a number of other tasks. Chemicals are often added to the water to
extend the life of the machinery and prevent biological growth in the
cooling towers. And many power plants return no water to the source - it
is all lost to evaporation. Other power plants return water to the source
at greatly elevated temperatures, destroying or radically altering the
local ecosystems.
These thermoelectric power plants are responsible for creating enormous
levels of stress on local, regional and national water supplies in the
U.S. and around the world. Besides some water used in module or turbine
manufacturing processes and a negligible amount needed to occasionally
clean them, solar and wind energy systems require no water to keep them
operating. Furthermore, the substitution of on-site solar thermal hot
water systems in place of electric water heaters also saves considerable
quantities of water.
Billions of gallons of water can be saved every day through the use of
solar, wind and other renewable energy systems. According to a United
States Geological Survey report published in 2000, 195 billion gallons of
water are withdrawn every day from our aquifers, lakes, rivers, and oceans
to cool thermoelectric power plants in the US. This water withdrawal
represents 48 percent of total water withdrawals in the United States.
Clean water is one of our most precious resources and it is at risk.
Government agencies from around the world are reporting that we are on the
verge of a worldwide water crisis. Global climate change, pollution,
inefficient irrigation methods, and population growth are the most common
contributing factors we hear about when this crisis is discussed. But the
generation of electricity using a thermoelectric power plant is also a
significant factor contributing to this crisis and a negative externality
that should not be dismissed.
Water demand is expected to continue to increase at twice the rate of
population growth. A big part of this increase is being created by the
demand for water to cool more power plants. In the next seven years India,
China and the U.S. plan to build 750 new coal-fired power plants. Another
340 coal plants are also planned throughout the world in the same
timeframe. And with the Federal Energy Bill now passed, new power plants,
including the possibility of a new generation of nuclear plants, are
expected to be built.
The generation of electricity using nuclear energy consumes the most water
- 0.62 gallons per kWh. Coal power plants use 0.49 gallons per kWh and a
combined cycle natural gas power plant uses 0.25 gallons per kWh.
Thermoelectric power plants withdraw 39 billion gallons of clean drinking
water from our aquifers every day (20% of total water withdrawals). This
is the equivalent to the daily drinking water requirements of 62 billion
people, about 10 times the Earth's population.
As the demand for water increases, competition for water resource will
continue to escalate and it will most likely result in local and regional
conflicts. Communities downstream from many of these power plants will
have less water available for their crops and for drinking. More conflicts
will arise within communities to determine water use priorities.
Today, water rights are significant issues in the US, Israel, China,
Africa and many other countries. Ismail Serageidin, a Vice President at
the World Bank, said, "If the wars of the 20th century were fought over
oil, the wars of the next century will be fought over water". And that
doesn't mean armed conflicts over oil, coal, natural gas and access to
nuclear materials will diminish either.
Renewable energy offers a multi-pronged solution. Using renewable energy
and embarking on intensive conservation programs can significantly reduce
the demand for water. Depending on location, a 100-watt solar panel will
save 2,000-3,000 gallons of water over the 25-year warrantee life of the
panel. All that water can stay in the aquifer until the next generation
needs it.
Aquifers are being drained at a record pace, putting the supply of
abundant and clean drinking water at great risk. Today, over one billion
people around the world do not have access to clean and safe drinking
water, and the number of people facing this crisis is increasing.
First-world nations like the U.S. will not always be insulated from this
dilemma.
All too often, the water-saving angle is a forgotten benefit of renewable
energy. We know solar, wind energy, and other renewable energy
technologies provide sustainable, clean sources of power. And it's now
becoming abundantly clear to even the most skeptical that renewable energy
technologies can be real engines of economic change, and provide some
level of geopolitical security through increased energy independence. It's
time to make sure that water conservation joins the growing list of
reasons to mobilize a real and widespread shift to renewable energy.
