The country's renewable energy chief stopped in town Friday, delivering an optimistic forecast of the future that included cheaper batteries and LED lights, cars with double the gas mileage and affordable solar projects.

David Danielson, the U.S. Department of Energy's assistant secretary for energy efficiency and renewable energy, also said his office wants wind turbines to generate 20 percent of the nation's power by 2030.

He cited the pilot project by Dominion Virginia Power off Virginia Beach as an encouraging example. Dominion, with a $47 million federal grant, has begun work to install two offshore turbines more than 550 feet tall to gather data for a possible larger project.

"This will be Virginia pioneering something nationally," said Danielson, speaking at a Hampton Roads Chamber of Commerce luncheon.

He said the move to renewable energy is crucial to decrease greenhouse gases emitted by existing power plants that lead to climate change.

"The climate issue is real," he said, paraphrasing a comment from his boss, U.S. Energy Secretary Ernest Moniz, who said last year he's "not interested in debating what is not debatable."

Danielson said developments in solar power technology are quickly bringing prices down.

"While you were sleeping, all of the sudden solar got cheaper without subsidies," he said.

Local builder Jeff Ainslie asked about federal incentives to retrofit older homes to be more energy efficient.

Danielson said obstacles that have hampered making buildings more efficient, which he described as "market barriers," are the most frustrating part of his job.

©2014 The Virginian-Pilot (Norfolk, Va.)