WASHINGTON — Steven Chu, the new secretary of energy, said Wednesday that solving the world's energy and environment problems would require Nobel-level breakthroughs in three areas: electric batteries, solar power and the development of new crops that can be turned into fuel.
Dr. Chu, a physicist, spoke during a wide-ranging interview in his office, where his own framed Nobel Prize lay flat on a bookcase, a Post-it note indicating where it should be hung on the wall.
He addressed topics that included global warming, renewable energy sources like solar and wind power, the use of coal and a proposed repository for nuclear waste at Yucca Mountain in Nevada.
Dr. Chu said a "revolution" in science and technology would be required if the world is to reduce its dependence on fossil fuels and curb the emissions of carbon dioxide and other heat-trapping gases linked to global warming.
Solar technology, he said, will have to get five times better than it is today, and scientists will need to find new types of plants that require little energy to grow and that can be converted to clean and cheap alternatives to fossil fuels.
Dr. Chu, who once called coal "a nightmare" in the way it is currently used, said the United States must also lead the world in finding a way to burn the fuel cleanly, because other countries with big coal reserves, like India and China, will not turn away from coal.
But Dr. Chu said such developments were not impossible. At the turn of the last century, he noted, scientists like Fritz Haber and Carl Bosch made Nobel-winning discoveries that allowed the development of cheap nitrogen fertilizers, saving Europe from starvation.
"I think science and technology can generate much better choices," Dr. Chu said. "It has, consistently, over hundreds and hundreds of years."
Dr. Chu said members of Congress who are drafting legislation to limit emissions of global warming gases had not yet sought his advice, although he added, "I would expect that they might."
He said that while President Obama and Congressional Democratic leaders had endorsed a so-called cap-and-trade system to control global warming pollutants, there were alternatives that could emerge, including a tax on carbon emissions or a modified version of cap-and-trade.
Dr. Chu said reaching agreement on legislation to combat climate change would be difficult in the current recession because any scheme to regulate greenhouse gas emissions would probably cause energy prices to rise and drive manufacturing jobs to countries where energy is cheaper.
"The concern about cap-and-trade in today's economic climate," Dr. Chu said, "is that a lot of money might flow to developing countries in a way that might not be completely politically sellable."
But, he said, he supports putting a price on carbon emissions to begin to address climate change.
The Energy Department is involved with efforts as varied as developing nuclear weapons and sequencing the human genome. Dr. Chu said the department's nuclear weapons program, which the White House is considering moving to the Defense Department, should be more tightly coupled to science in critical tasks like safeguarding nuclear materials and detecting nuclear proliferation.
One major decision facing his department is what to do about Yucca Mountain, a site 100 miles from Las Vegas chosen by Congress for burial of high-level radioactive waste. Mr. Obama and the Senate majority leader, Harry Reid of Nevada, have opposed the project.
Dr. Chu said the political difficulties in trying to obtain a license for the Yucca Mountain site should serve as a guide in searching for other nuclear waste repositories in the future. "There are political realities," he said.
Last year, the Nuclear Regulatory Commission, which has the final say, began work on an application from the Energy Department for a license for the project. Dr. Chu said the Energy Department should continue to answer questions from the Nuclear Regulatory Commission about the application and then let the commission make a decision.
Dr. Chu would not say whether the department would open the site if allowed to do so. But, he said, "you can put a hold on" preparation.
The electric utilities, he noted, expected the department to live up to contracts signed in the 1980s for it to dispose of the nuclear waste.
Dr. Chu said he was still adjusting to his surroundings and title after most of a career spent as an academic scientist. Asked whether he preferred to be called "Dr. Chu" or "Mr. Secretary," he answered, "Steve is fine."
