Matthew Stepp is a senior policy analyst at the nonpartisan Information Technology & Innovation Foundation.
We’re losing the race against global warming. Worldwide coal production increased about eight times faster than solar- and wind-power generation last year. China added more new coal plants in 2011 than are running in Texas and Ohio, even as it leads the world in wind-power capacity. Meanwhile, the United States is only modestly cutting carbon emissions by transitioning from coal to natural gas, which is still a carbon-rich fuel.
Despite these trends, conventional wisdom holds that a “clean-energy future” is not only possible but looming. Through a combination of energy efficiency and renewable technologies, some argue, we can “solve” the problem of climate change.
The case for “we’ve got all the renewables we need” recently received a boost from a National Renewable Energy Laboratory (NREL) study, which concluded: “Renewable electricity generation from technologies that are commercially available today, in combination with a more flexible electric system, is more than adequate to supply 80% of total U.S. electricity generation in 2050 while meeting electricity demand on an hourly basis in every region of the country.” Physicist Amory Lovins, a leading advocate of green energy, was among those praising the study. It showed “how to produce 80 to 90 percent of America’s electricity from proven, reliable and increasingly competitive renewable sources like the sun and wind,” he said.
Yet on close reading, the study not only doesn’t support these optimistic claims, it also reveals the need for a more diverse technology strategy and aggressive investments in innovation.
For starters, the study doesn’t find that wind and solar can, even theoretically, supply 80 to 90 percent of U.S. power by 2050. In the best case, less than half would come from wind and sun. The remaining balance of renewable power would come from new hydropower, equivalent to adding 50 Hoover-size dams and building biomass plants equal in capacity to the U.S. nuclear fleet; the biomass plants are unlikely to be carbon-neutral.
Even achieving the goal of 50 percent of the U.S. power supply from solar and wind assumes that 100 to 150 gigawatts of energy storage, or roughly half the size of the country’s coal capacity, will emerge to provide power when the sun isn’t shining and the wind isn’t blowing. While pumped hydro-storage is available in some locations today, other technology options, such as very large batteries and compressed air, require significantly more innovation to become cost- effective at commercial scale.
In fact, the study’s storage estimate may be low, because it assumes that the number of residences and businesses that will go offline at peak times when wind and solar aren’t available are equivalent to 1½ New York states. It also assumes no growth in U.S. electric consumption for the next 40 years, thanks to improvement in energy efficiency. Consider that California’s energy-efficiency efforts lead the world — but demand has still increased 25 percent in the Golden State in the past 20 years.