Nearly 140 countries could be powered 100 percent by solar, wind, hydropower and geothermal energy by 2050, a group of researchers say.
Such a future could also mean a need for 42.5 percent less energy globally, because the efficiency of renewable sources, the scientists and engineers claim. In addition, this shift could lead to a net increase of roughly 24.3 million long-term full-time jobs, an annual decrease of up to 7 million deaths from air pollution annually, savings of more than $50 trillion in health and climate costs per year, and avoid 1.5 degrees Celsius of global warming, they say.
This new study is a followup to hotly debated research appearing in 2015 suggesting that the United States could switch to 100 percent clean, renewable energy by 2050. It now covers nearly the entire world.
The scientists analyzed 139 countries for which data was publicly available from the International Energy Agency. These 139 collectively emit more than 99 percent of the global warming gas carbon dioxide worldwide. They analyzed what raw renewable energy resources were available to each country, and investigated what each needed to electrify their transportation, heating, cooling, industrial, agricultural, forestry and fishing sectors.
The researchers calculate that these 139 countries could be powered 80 percent by clean, renewable energy by 2030 and 100 percent by 2050. The mix of resources they envision for the 2050 goal include:
- 21.36 percent from photovoltaic solar plants
- 9.72 percent from concentrated solar plants
- 14.89 percent from residential rooftop solar
- 11.58 percent from commercial and government rooftop solar
- 23.52 percent from onshore wind
- 13.62 percent from offshore wind
- 4 percent from hydroelectric energy
- 0.58 percent from wave energy
- 0.67 percent from geothermal energy
- 0.06 percent from tidal turbine energy
“What I find most exciting about the results of this study is that every country that we examined has sufficient resources to power itself, although in the case of a couple of tiny countries with very high populations, this might require either importing energy from their neighbor or using an unusually high amount of offshore energy,” says study leader Mark Z. Jacobson, director of Stanford University's Atmosphere and Energy Program.
The scientists found that countries with the highest amount of land per person, such as the United States, China, and the members of the European Union, generally had an easier time adopting 100 percent renewable energy because of the greater ease they had finding sites for solar, wind, hydropower and geothermal power “and the greater abundance of such resources in those countries,” Jacobson says. “Densely populated countries may have a more difficult time.”
The researchers note that their roadmap is far more aggressive than what the Paris climate agreement calls for. But it is still technically and economically feasible, and the roadmap’s overall cost to society in terms of energy, health, and climate are one-quarter that of the current fossil fuel system. Although they estimate this shift would lead to 27.7 million jobs lost, they say it would also create 50 million jobs.
“It's most important and surprising that we can obtain such large social benefits—near-zero air pollution and climate change—at essentially no extra cost,” says study co-author Mark Delucchi, a research engineer at the University of California at Berkeley's Transportation Sustainability Research Center.
Although the 2015 study in the Proceedings of the National Academy of Sciences, which made similar claims for the United States, drew heated criticism, “most of the criticisms of the PNAS paper don't really pertain to the 139-country paper, because most of those criticisms were focused on supply-demand grid balancing, which the 139-country paper doesn't do,” Delucchi says.
The researchers note their focus on solar, wind, hydropower and geothermal power has drawn some criticism for excluding nuclear power, carbon capture and sequestration from coal, and biofuels. Their reasons for not including nuclear power include the decade or two it can take between planning and operation, its high cost, and its risks of meltdown, waste, and weapons proliferation. They also say they left off “clean coal” and biofuels because both still cause air pollution and emit carbon dioxide.
“We are next developing roadmaps for individual cities to go to 100 percent clean, renewable energy,” Jacobson says.
Jacobson, Delucchi, and their 25 colleagues detailed their findings online 23 August in the journal Joule.
Charles Q. Choi is a science reporter who contributes regularly to IEEE Spectrum. He has written for Scientific American, The New York Times, Wired, and Science, among others.