Water Shortages to Hit Green Energy, Shale

Ken Silverstein | Jul 08, 2011

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Leaders are pondering the nation's energy fate without adequately considering the effect that such policies will have on limited water supplies. Energy production is water-intensive -- a fact that could likely impede green energy development as well as that of shale gas.

Those are the findings of the World Policy Institute that emphasizes to political leaders that they must consider the nexus between energy policy and water consumption. Indeed, the technologies to reduce carbon emissions are coming to the fore. But some of those ideas require high levels of water -- a scarce resource that is required by all energy forms.

In this country, droughts have decreased the pool of water now available to all concerns. Not only do utilities use it. So does big industry and small residential households. To compound the matter, the demand for electricity here is expected to rise by 1.5 percent a year over 20 years. Governments and businesses alike are now calling for concerted conservation efforts. Another approach being pushed is the development of new utility technologies that require less water.

In Texas, the combination of hot summers and water shortages are pitting farmers against shale-gas developers. Diana Glassman, who co-authored the report for the think tank, says 13 million gallons of water are required in the southern portion of the state. The idea that shale-gas will become the next gold rush is therefore jeopardized, particularly because its production requires seven times the amount of water as does the extraction of conventional natural gas.

"The competition between water and energy needs represents a critical business, security, and environmental issue, but it has not yet received the attention that it deserves," says Glassman. "Energy production consumes significant amounts of water, and vice versa. In a world where water scarcity is a major and growing challenge, water deserves a place on the energy agenda alongside cost, carbon and security considerations."

Conservation Key

According to the World Policy Institute, coal-and-oil-fired power plants consume roughly twice the water than that of gas-fired facilities while nuclear generation needs three times that of natural gas. Cleaner coal technologies such as coal gasification will reduce that need by as much as half but, emerging concepts like carbon capture and burial could increase consumption between 30-100 percent.

Wind and rooftop solar panels, meantime, are the most efficient forms of generation when it comes to water. However, large and commercial solar plants use twice the water as coal and five times the amount as gas-fired plants. Further, corn-based bio-fuels used in transportation consume much greater amounts of water than does the drilling for traditional oil.

The National Energy Technology Laboratory adds that the average thermoelectric plant uses 25 gallons of water to produce one kilowatt-hour of power using current technologies. If a household uses 1,000 kilowatt-hours a month, then 25,000 gallons of water must be withdrawn to provide that power from a coal-fired power plant.

The number jumps to 31,000 gallons a month if nuclear power is used to generate that electricity. Natural gas plants, however, use much less water. By comparison, a typical household might consume 10,000 gallons of water a month.

Most power plants today use "once-through colling" in which nearly all the water is returned to the source. Less than 1 percent is lost through evaporation or leaks in the system, says the U.S. Department of Energy. Newer technologies use "closed loop" systems that rely on "cooling towers" and "re-circulate" the water.

Access to fresh water supplies is a universal issue extending well beyond the United States. But developing nations are having the toughest time. The problems are exacerbated because of the fears of climate change. The United Nations Foundation's Global Water Challenge says that about a third of all countries now have water scarcity issues and that this level could rise to two-thirds in 20 years because of global warming.

"Water is the new oil," says Jim Rogers, chief executive of Duke Energy, in a talk with this writer. When utilities formulate their energy portfolios, they must take water availability into consideration.

Any exacerbation of the current water shortages will weigh heavily on all concerns and particularly on utilities that require large quantities of water to produce electricity. Newer technologies will eventually alleviate some of the pressures. But the whole issue underscores why energy efficiency must become a focal point of American public policy.

EnergyBiz Insider has been named Honorable Mention for Best Online Column by Media Industry News, MIN. Ken Silverstein has also been named one of the Top Economics Journalists by Wall Street Economists.

Follow Ken on www.twitter.com/ken_silverstein

energybizinsider@energycentral.com.

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Comments

Need to be careful about semantics

If a typical coal-fired plant is roughly 32% efficient thermally, the amount of water evaporated due to heating in the condenser and flue gas cooling is about 6 pounds--or 0.72 gallons per KWh.  Makeup water for a boiler is typically a quite small figure, somewhere around 0.09 pounds per KWh.  There are other uses such as bottom ash quenching in PC boilers and scrubbers but the figure relating to water actually lost--that is  unrecoverable due to evaporation is much smaller than 25 gallons per KWh.

If a typical nuclear plant thermal efficiency is about 27%, the water loss due to evaporation is about 0.92 gallons per KWh.  Add in for makeup and some spent fuel cooling, and the permanent loss to vaporization might be 1 to 1.2 gallons per KWh.

Once-through cooling may withdraw 25 to 50 gallons per KWh but the bulk of the water is returned as warm water which will lose a relatively small amount per gallon to vaporization--how much depends on ambient conditions.  In reality, cooling towers do not significantly alter the amount of vaporized water if one looks at the whole water cycle.  Their main advantage is they do not withdraw as much water from a source and do not put as much warm water, which may contain corrosion inhibitors and biocides, back into a body of water.

Water Shortages Created by Energy Projects

Using reclaimed water e.g. treated sewage contributes to reducing a power plant’s external water demands – lessening impact to natural water resources. During an EIS review water demands are identified as are the sources of supply. State environmental regulators often required recirculation or alternated methods (i.e. use of reclaimed sewage) to lessen impact to water resources. Please consider extract from a previous email

At Florida Power & Light's planned West County Energy Center, FPL intends to increase the power-generating capacity of the plant from 3,300 megawatts per day to 3,800 megawatts. To avoid the drought-like conditions expressed in "Sinking Water and Rising Tensions Dec 5" about 21 million gallons a day of treated sewage from throughout south Palm Beach County, Lake Worth and West Palm Beach will be used to cool the plant's generators. The use of treated sewage, euphemistically termed "reclaimed water" negates FPL's previous plans calling for using water from underground aquifers.

Florida along with other rapid growth and water scarce states [CA, NV, TX] have mandated reclaimed water for non-potable purposes e.g. landscape and golf course irrigation. Reuse of treated sewage has been implement from the 1970's [Lake Tahoe, CA and Dan Sewage Reclamation Project Rishon Letzion, Israel] to the present; cost-effective technology has been developed to achieve treatment viability - protecting public health and using demonstrated technology. Perhaps other electric utilities and regulators should consider FPL's example and explore use of treated sewage as a viable source of cooling water.

Dr. Richard W. Goodwin, P.E.
Environmental Engineering Consultant

Use wind, save water

Thanks for including the statement about wind and rooftop solar being low water users. Wind uses virtually no water, an important consideration throughout much of the arid (and growing in population) western U.S.  More info in the USDOE fact sheet The Wind/Water Nexus: http://www.nrel.gov/docs/fy06osti/37790.pdf . --Regards, Tom Gray, Wind Energy Communications Consultant