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.
Furthermore, to meet the goal of having 50 percent of the U.S. power supply come from solar and wind sources, the study presumes a doubling of the U.S. transmission system that is simply not feasible. Nearly every mile of new U.S. transmission lines is fought over by the localities they run through. And the report is mum on what happens to electricity reliability or consumer costs if more than one of these assumptions fails to materialize.
Simply put: Far from a realistic plan, the NREL study suggests what might be possible in an ideal world. The authors even admit that although their analysis suggests “a high renewable generation future is possible, a transformation of the electricity system would need to occur . . . involving every element of the grid.”
Certainly, better efficiency and increased wind and solar power will be among the ways to address global warming. But placing all of our bets on today’s renewable technologies is unwise. A more sensible approach would be to invest in improving the performance and cost of a broad range of zero-carbon technologies through innovation, including better and cheaper wind and solar power as well as energy storage.
We must also be realistic about fossil fuels, which provide 87 percent of the planet’s energy and aren’t disappearing anytime soon. The United States needs to bring commercially proven carbon capture and storage to scale and reduce its cost. It also would be prudent to explore cheaper next-generation nuclear technologies that offer better safety, waste and security options than the Fukushima-type light-water designs that were locked in during the Eisenhower administration.
The real lesson of the NREL study is that much more innovation is necessary to achieve deep and affordable carbon reductions. Yet almost all of the policy and funding today focuses on deploying current technologies. U.S. investment in energy innovation is less than 5 percent of federal spending on defense research and demonstration. That has to change. We need better, cheaper options if the grid is to produce less carbon.