In a penetrating and provocative talk on the opening day of an IEEE photovoltaics specialists conference, on June 8, the U.S. Department of Energy’s Samuel F. Baldwin drew attention to a recent report assessing what it will take in terms of generation to meet the country’s stated carbon reduction goals. Walter Short and Patrick Sullivan of the National Renewable Energy Laboratory modeled the U.S. electricity system to identify the main effects of cutting U.S. carbon emissions 80 percent by 2050, as the Obama administration has promised. The results are arresting. Average electricity prices increase only modestly, to 10.5 cents per kilowatt-hour from 9 cents/kWh. Carbon prices, however, range from $80 to $100, five or six times present-day trading levels.
The NREL linear programming exercise found that with carbon emissions just one-fifth of what they are now in 2050, renewables account for almost half of U.S. electricity, but most of that is wind—solar concentrators contribute a significant share, but the role of photovoltaics is still minor. As for traditional fuels, the amount of electricity generated by coal contracts sharply, by about a third, and natural gas's generation decreases appreciably; nuclear holds about steady but does not increase.
The NREL report tends to reinforce what has been an Energywise refrain--that when we talk about renewables, it's really just one renewable, namely wind. Photovoltaic electricity is further from "grid parity" than its proponents would like us to think, and even when a kind of theoretical parity is achieved, a truly big break into the market may still be years away. Pretty much the same message is found in a major report issued this week by the National Academies, “Electricity from Renewable Resources: Status, Prospects, and Impediments.”
The Academies report endorsed the view of an earlier Department of Energy study that wind could generate 20 percent of U.S. electricity by 2020, provided--it emphasizes--that transmission and distribution bottlenecks are adequately addressed. If renewables are to contribute another 20 percent of generation in the next two decades to 2040, concludes the report, wind will continue to be the main player. Solar concentrators will play a growing role, but not necessarily PV.