Hard behind the boom in renewable-energy-project construction is a boom in demand for technologies to store electricity. Wind farms generate when the wind blows and solar-power stations generate when the sun shines, but demand continues. So utilities must fill in with coal, gas and other fuels that can respond quickly.

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Rather than construct 100 MW of gas-fueled backup capacity for every 100 MW of wind or solar generation, power engineers are developing a spectrum of technologies to store electricity for contingencies ranging from momentary voltage blips to hours-long frequency deviations. More than 250 people gathered on July 14-16 in San Diego for the Infocast Power Storage Projects and Enabling Technologies Summit to explore the drivers, technologies and economics that are shaping the power- and energy-storage markets.

Laws in 25 states and the District of Columbia now require utilities to eventually obtain as much as 30% of their power from renewable energy, up from less than 2% today. But the variability of wind and sunshine seriously handicap the two fastest-growing technologies. Speakers reminded attendees that Texas came perilously close to a blackout last February when a sudden drop in wind coincided with the onset of the evening demand and unplanned outages of other energy providers.

Flywheels, batteries and even supercapacitors able to discharge up to 2,000 kW in seconds now are being developed to provide transmission stability and power quality, critical for digital equipment. Pumped-hydro storage, compressed-air energy storage (CAES) and other technologies able to store thousands of megawatts were successfully developed in the 1980s, but interest in them waned in the 1990s as energy prices fell, noted keynote speaker Brett A. Perlman, former commissioner of the Texas Public Utilities Commission and now vice president of strategy and business development at Atreides Capital LLC, Houston.

With the almost universal push for alternative-energy generation, new energy-storage projects may be finally starting to move again. The Iowa Stored Energy Plant Agency currently is preparing to drill two test wells for what could be the first CAES project in the U.S. since a 110-MW plant was completed in 1991 in McIntosh, Ala. The project in Dallas Center, Iowa, will inject compressed air into an aquifer at night when demand on the grid is low. When required, it will be able to generate 268 MW of power with a mixture of compressed air and natural gas in a combustion turbine. Costs are still being worked out, but Development Director Kent Holst said it appears the plant will cost about $900 per installed kilowatt.

“Cost reductions in large-scale storage have been incremental and largely due to packaging, better understanding of the system and identification of more benefits,” says Imre Gyuk, energy-storage-research program manager for the U.S. Dept of Energy. “Regulation of storage and substation peak-load reduction are the topics that have been emerging as goals for the near future.”

Attendees included utility managers, venture capitalists, lawyers, researchers and consultants. The presence of representatives from venture-capital firms both in the audience and as speakers highlighted the power-storage market’s potential for investment and growth.

Kleiner Perkins Caufield & Byers, whose cash fueled much of the Silicon Valley boom in the 1990s, sees energy storage as “a promising field for investment,” said David Wells, attending for the firm. But he said the firm is proceeding with caution. “We have no experience with regulated markets,” he explained.