(Bloomberg News) Power producers in the U.S. aren't calculating the cost of often scarce water resources for such energy sources as nuclear, coal, natural gas and biomass, according to a report.

The Civil Society Institute and the Environmental Working Group report titled "The Hidden Costs of Electricity: Comparing the Hidden Costs of Power Generation Fuels" found that crop irrigation for a biomass plant can use as much a 100,000 gallons of water to make 1 megawatt-hour, the groups said today in a statement. Coal and nuclear use as much as 50,000 and 60,000 gallons for the same power, respectively.

The report, prepared by Synapse Energy Economics Inc., contrasted that to the amount of water used by photovoltaic and dry-cooled solar thermal power and wind power, which require little water use to make electricity.

Government and industry are "flying blind" in planning for continued reliance on fossil fuels, nuclear and industrial biomass, said Grant Smith, senior energy analyst at CSI. "Each of these is water-intensive and leads to pollution of water," and are "increasingly scarce and in competition for other uses such as agriculture and other commercial uses."