By Andrew Maykuth, INQUIRER STAFF WRITER

Daniel Yergin, one of the most influential voices in the world of energy, says shale gas is here to stay.

“Shale gas has come on really fast,” Yergin, an author and energy analyst, said in an interview Monday. “But people don’t realize it’s 30 percent of our gas production. It’s not a question of whether to do it or not. It’s happened.”

Yergin, who is a member of a presidential shale-gas advisory commission, said it’s important to develop resources like Pennsylvania’s Marcellus Shale “responsibly,” adhering to best environmental practices while responding to local community concerns.

Yergin is in Philadelphia to speak Monday night at the Free Library, where he is promoting his latest book, The Quest, a comprehensive examination of the energy business. Yergin won the Pulitzer Prize in 1992 for a history of the oil industry, The Prize, and is chairman of IHS Camridge Energy Research Associates.

Natural gas from shale formations, which is extracted using a process called hydraulic fracturing, is only one component in a diversified energy universe, including fossil fuels, renewable energy and energy conservation, Yergin said.

But shale-gas has the potential to rapidly reorder the energy world, he said.

“Shale gas really could change the economics across the energy realm,” he said. “It’s a relatively low-carbon, low-cost fuel.”

He said the growth of natural gas supplies will mostly affect electricity production and the petrochemical industries, though he sees only limited applications as a motor fuel, as some natural gas advocates are proposing.

Environmental opposition has developed almost as swiftly as the market share for shale gas. “The opposition and criticism has come very fast, too,” he said.

Yergin is a member of President Obama’s energy subcommittee that examined shale-gas. The committee in August called for improvements to hydraulic fracturing process, but disappointed anti-drilling activists by endorsing shale-gas development.

He will speak on a broad range of energy topics at 7:30 p.m. at the Free Library of Philadelphia, 1901 Vine St.

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