From the American Association for the Advancement of Science:
...Ernest Moniz, a professor of physics and engineering systems at MIT, sketched a roadmap to a low-carbon future but acknowledged that it is not going to be easy to achieve. “I’m optimistic on the technology side,” Moniz said. “On the policy side, I’m less confident.”...
...So given the need for multiple technology pathways, Moniz offered what he called his Michelin Guide of worthwhile approaches. In his three-star category, he calls for increased improvements in energy efficiency and pursuit of carbon-free electricity in all its forms, including nuclear power, coal and natural gas with carbon dioxide capture and sequestration, and renewable energy sources such as wind, geothermal, and solar.
He gives two stars to alternative transportation fuels, such as biofuels and electricity. He also gives two stars to improvements in electric power grids and other infrastructure upgrades for energy delivery systems, and emphasizes the importance of natural gas in the transition to a low-carbon future.
As a one-star option, Moniz said it is time to get more serious about adaptation technologies and to begin to understand geoengineering measures quantitatively. Moniz acknowledged that geoengineering was “not discussed in polite company only a few years ago” and said he remains “relatively terrified” about its prospects. But “we need to understand the options just in case we don’t get the policy, business, and technology innovations rapidly enough and are forced to contemplate a hopefully short-term geoengineering intervention,” he said.
Discussing the technologies on his three-star wish list, Moniz noted the huge upfront capital costs for building nuclear power plants. But he said nuclear almost certainly will need to play a role in any serious effort to reach a low carbon future by 2050 or beyond.
His near-term priorities for nuclear include: building 10 gigawatts of so-called “first mover” plants, subsidizing facilities with design and production innovations aimed at bringing costs down; moving spent fuel at existing nuclear plants to a centralized storage location; and doing robust R&D on nuclear fuel cycle options. To enhance the nonproliferation regime, he said, nations should pursue international fuel leasing arrangements that provide assured adequate supplies of nuclear fuel to countries with small nuclear power programs and return spent fuel to the countries of manufacture.
Moniz stressed that there is no need to rush into “closed” nuclear fuel cycles, in which spent fuels are reprocessed to separate out plutonium. “The fact is we have lots of uranium,” Moniz said. Even with a tripling of the number of U.S. power reactors, he said, there is enough uranium available to fuel the new reactors for their 50-year lifetimes.
Regarding low-carbon use of coal, Moniz said there still is much to learn about the feasibility of carbon sequestration at a very large scale, which involves the capture of carbon dioxide emissions at the power plant for injection into geological formations such as hydrocarbon reservoirs or deep saline aquifers. Since trading of carbon credits typically is a part of any carbon sequestration proposal, Moniz said it is essential to develop adequate verification and monitoring techniques in order to monetize the stored carbon dioxide.
By one estimate, 92 percent of the coal plants projected to be on line in the U.S. in 2030 already exist. Retrofitting of carbon dioxide scrubbers onto existing plants is expected to be quite expensive, and not all sites will have sufficient land and water available to house the new equipment.
“We don’t know whether we can eventually retrofit 60 percent or 10 percent of existing coal plants economically,” Moniz said. If the figure is more like 10 percent, he said, switching to natural gas as a fuel at the plants may become a critical option. The U.S. has a lot of natural gas available from unconventional sources such as shale, Moniz said, but there must be more research on the sustainable growth rate for natural gas as a power source.
When it comes to solar power, Moniz said he is “extremely bullish for the long term.” But here, too, there are unanswered questions such as how quickly solar can be scaled up for widespread use. With government support, the costs of solar have been coming down, Moniz said, and there is a very active research effort underway at MIT and elsewhere to develop new, more efficient materials for converting solar energy into electricity. At MIT, he said, at least 40 faculty members are doing research related to various types of solar energy studies....MORE