amount of fresh water consumed for world energy production is on track to
double within the next 25 years, the International Energy Agency (IEA)
even though frackingâ€”high-pressure hydraulic fracturing of underground rock
formations for natural gas and oilâ€”might grab headlines, IEA sees its future
impact as relatively small.
the largest strain on future water resources from the energy system, according
to IEA's forecast, would be due to two lesser noted, but profound trends in the
energy world: soaring coal-fired electricity, and the ramping up of biofuel
today's policies remain in place, the IEA calculates that water consumed for
energy production would increase from 66 billion cubic meters (bcm) today to
135 bcm annually by 2035.
an amount equal to the residential water use of every person in the United
States over three years, or 90 days' discharge of the Mississippi River. It
would be four times the volume of the largest U.S. reservoir, Hoover Dam's Lake
than half of that drain would be from coal-fired power plants and 30 percent
attributable to biofuel production, in IEA's view. The agency estimates oil and
natural gas production together would account for 10 percent of global
energy-related water demand in 2035. (See related quiz: "What
You Don't Know About Biofuel.")
everyone agrees with the IEA's projections. The biofuel industry argues that
the Paris-based agency is both overestimating current water use in the ethanol
industry, and ignoring the improvements that it is making to reduce water use.
But government agencies and academic researchers in recent years also have
compiled data that point to increasingly water-intensive energy production.
Such a trend is alarming, given the United Nations' projection that by 2025, 1.8
billion people will be living in regions with severe water scarcity, and that
two-thirds of the world's population could be living under water-stressed
and water are tightly entwined," says Sandra Postel, director of theGlobal Water Policy Project, and National
Geographic's Freshwater Fellow. "It takes a great deal of energy to supply
water, and a great deal of water to supply energy. With water stress spreading
and intensifying around the globe, it's critical that policymakers not promote
water-intensive energy options."
IEA, established after the oil shocks of the 1970s as a policy adviser on
energy security, included a warning on water in a special report within its
latest World Energy Outlook released late last year. "A more
water-constrained future, as population and the global economy grow and climate
change looms, will impact energy sector reliability and costs," the agency
Geographic News obtained from IEA a detailed breakdown of the figures, focusing
on the agency's "current policies" scenarioâ€”the direction in which
the world is heading based on current laws, regulations, and technology trends.
energy realm, IEA sees coal-powered electricity driving the greatest demand for
water now and in the future. Coal power is increasing in every region of the
world except the United States, and may
surpass oil as the world's main source of energy by 2017. (See related interactive
Global Electricity Mix.)
coal plants always have required large amounts of water, but the industry move
to more advanced technologies actually results in greater water consumption,
IEA notes. These advanced plants have some environmental advantages: They
discharge much less heated water into rivers and other bodies of water, so
aquatic ecosystems are protected. But they lose much more water to evaporation
in the cooling process.
same water consumption issues are at play in nuclear plants, which similarly
generate steam to drive electric turbines. But there are far fewer nuclear
power plants; nuclear energy generates just 13 percent of global electricity
demand today, and if current trends hold, its share will fall to about 10
percent by 2035. Coal, on the other hand, is the "backbone fuel for
electricity generation," IEA says, fueling 41 percent of power in a world
where electricity demand is on track to grow 90 percent by 2035. Nuclear plants
account for just 5 percent of world water consumption for energy today, a share
that is on track to fall to 3 percent, IEA forecasts. (See related quiz: "What
You Don't Know About Water and Energy.")
today's trends hold steady on the number of coal plants coming on line and the
cooling technologies being employed, water consumption for coal electricity
would jump 84 percent, from 38 to 70 billion cubic meters annually by 2035, IEA
says. Coal plants then would be responsible for more than half of all water
consumed in energy production.
power producers could cut water consumption through use of "dry
cooling" systems, which have minimal water requirements, according to IEA.
But the agency notes that such plants cost three or four times more than wet
cooling plants. Also, dry cooling plants generate electricity less efficiently.
surest way to reduce the water required for electricity generation, IEA's
figures indicate, would be to move to alternative fuels. Renewable energy
provides the greatest opportunity: Wind and solar photovoltaic power have such
minimal water needs they account for less than one percent of water consumption
for energy now and in the future, by IEA's calculations. Natural gas power
plants also use less water than coal plants. While providing 23 percent of
today's electricity, gas plants account for just 2 percent of today's energy
water consumption, shares that essentially would hold steady through 2035 under
IEA report includes a sobering analysis of the water impact of carbon capture
and sequestration (CCS) technology. If the world turns to CCS as a way to cut
greenhouse gas emissions from coal plants, IEA's analysis echoes that of
outside researchers who have warned that water consumption will be just as
great or worse than in the coal plants of today. "A low-carbon solution is
not necessarily a low-water solution," says Kristen Averyt, associate
director for science at the Cooperative Institute for Research in Environmental
Sciences at the University of Colorado.Â However, based on current government
policies, IEA forecasts that CCS would account for only 1.3 percent of the
world's coal-fired generation in 2035. (See related story: "Amid
Economic Concerns, Carbon Capture Faces a Hazy Future.")
coal power, biofuels are on track to cause the largest share of water stress in
the energy systems of the future, in IEA's view. The agency anticipates a 242
percent increase in water consumption for biofuel production by 2035, from 12
billion cubic meters to 41 bcm annually.
potential drain on water resources is especially striking when considered in
the context of how much energy IEA expects biofuels will deliverâ€”an amount that
is relatively modest, in part because ethanol generally produces less energy
per gallon than petroleum-based fuels. Biofuels like ethanol and biodiesel now
account for more than half the water consumed in "primary energy production"
(production of fuels, rather than production of electricity), while providing
less than 3 percent of the energy that fuels cars, trucks, ships, and aircraft.
IEA projects that under current government policies, biofuels' contribution
will edge up to just 5 percent of the world's (greatly increased)
transportation demand by 2035, but fuel processed from plant material will by
then be drinking 72 percent of the water in primary energy production.
consumes a lot of water," says Averyt. Evaporation is the culprit, and
there is great concern over losses in this area, even though the water in
theory returns to Earth as precipitation. "Just because evaporation
does not mean it will rain here,"
says Averyt. Because irrigation is needed most in arid areas, the watering of
crops exacerbates the uneven spread of global water supply.
worry that water demand for fuel will sap water needed for food crops as world
population is increasing. "Biofuels, in particular, will siphon water away
from food production," says Postel. "How will we then feed 9 billion
people?" (See related quiz: "What
You Don't Know About Food, Water, and Energy.")
irrigation rates vary widely by region, and even in the same region, farming
practices can vary significantly from one year to the next, depending on
rainfall. That means there's a great deal of uncertainty in any estimates of
biofuel water-intensity, including IEA's.
example, for corn ethanol (favored product of the world's number one biofuel
producer, the United States), IEA estimates of water consumption can range from
four gallons to 560 gallons of water for every gallon of corn ethanol produced.
At the low end, that's about on par with some of the gasoline on the market,
production of which consumes from one-quarter gallon to four gallons water per
gallon of fuel. But at the high end, biofuels are significantly thirstier than
the petroleum products they'd be replacing. For sugar cane ethanol (Brazil's
main biofuel), IEA's estimate spans an even greater range: from 1.1 gallon to
2,772 gallons of water per gallon of fuel.
not entirely clear how much biofuel falls at the higher end of the range. In
the United States, only about 18 to 22 percent of U.S. corn production came
from irrigated fields, according to the U.S. Department of Agriculture. And the
remaining water in ethanol production in the United Statesâ€”the amount consumed
in the milling, distilling, and refining processesâ€”has been cut in half over
the past decade through recycling and other techniques, both industry sources
and government researchers say. (One industry survey now puts the figure at 2.7
gallons water per gallon of ethanol.) A number of technologies are being tested
to further cut water use.
absolutely has been a major area of focus and research and development for the
industry over the past decade," says Geoff Cooper, head of research and
analysis for the Renewable Fuels Association, the U.S.-based industry trade
group. "Our member companies understand that water is one of those
resources that we need to be very serious about conserving. Not only is it a
matter of sustainability; it's a matter of cost and economics."
potential solution is to shift from surface spraying to pumped irrigation,
which requires much less water, says IEA. But the downside is those systems
require much more electricity to operate.
use also could be cut with advanced biofuels made from non-food, hardy plant
material that doesn't require irrigation, but so-called cellulosic ethanol will
not become commercially viable under current government policies, in IEA's
view, until 2025. (If governments enacted policies to sharply curb growth of
greenhouse gas emissions, IEA's scenarios show cellulosic ethanol could take
off as soon as 2015.)
and other unconventional techniques for producing oil and natural gas also will
shape the future of energy, though in IEA's view, their impact on water
consumption will be less than that of biofuels and coal power. Water
consumption for natural gas production would increase 86 percent to 2.85
billion cubic meters by 2035, when the world will produce 61 percent more natural
gas than it does today, IEA projects. Similarly, water consumption for oil
production would slightly outpace oil production itself, growing 36 percent in
a world producing 25 percent more oil than today, under IEA's current policies
global projections may seem modest in light of the local water impact of
fracking projects. Natural gas industry sources in the shale gas hot spot of
Pennsylvania, for instance, say that about 4 million gallons (15 million
liters) of water are required for each fracked well, far more than the 100,000
gallons (378,540 liters) conventional Pennsylvania wells once required.
Gas Out of Rock With Water")
stresses that its water calculations are based on the entire production process
(from "source to carrier"); water demand at frack sites is just one
part of a large picture. As with the biofuel industry, the oil and gas industry
is working to cut its water footprint, IEA says. "Greater use of water
recycling has helped the industry adapt to severe drought in Texas" in the
Eagle Ford shale play, said Matthew Frank, IEA energy analyst, in an email.
volumes of water used in shale gas production receive a lot of attention (as
they are indeed large), but often without comparison to other industrial
users," Frank added. "Other sources of energy can require even
greater volumes of water on a per-unit-energy basis, such as some biofuels. The
water requirements for thermal power plants dwarf those of oil, gas, and coal
production in our projections."
said, IEA does see localized stresses to production of fossil fuels due to
water scarcity and competitionâ€”in North Dakota, in Iraq, in the Canadian oil
sands. "These vulnerabilities and impacts are manageable in most cases,
but better technology will need to be deployed and energy and water policies
better integrated," the IEA report says. (See related story: "Natural
Gas Nation: EIA Sees U.S. Future Shaped by Fracking.")
in Postel's view, the silver lining in the alarming data is that it provides
further support for action to seek alternatives and to reduce energy use
altogether. "There is still enormous untapped potential to improve energy
efficiency, which would reduce water stress and climate disruption at the same
time," she says. "The win-win of the water-energy nexus is that
saving energy saves water."