A rapid transition away from fossil fuels is the only way to achieve the historic Paris agreement's most ambitious goal of limiting global temperature rise to 1.5 degrees Celsius above pre-industrial levels, according to a new study led by Mark Z. Jacobson, a professor of civil and environmental engineering at Stanford. Jacobson and 26 coauthors have produced roadmaps for 139 countries, representing 99 percent of worldwide emissions, to transition to all clean, renewable energy by 2050. Previously, Jacobson and colleagues had produced detailed roadmaps for all 50 U.S. states to transition to 100-percent clean, renewable energy without fossil fuels, nuclear power or biofuels by 2050.

“These roadmaps provide the first specific plans ever produced by country for the world to avoid 1.5 degrees Celsius global warming,” Jacobson said. “The beautiful part is that such a transition will also create over 20 million more permanent full-time jobs than lost worldwide, save consumers money and avoid over 3 percent of each country’s GDP in air pollution health costs alone.”

Jacobson and his collaborators detail individual plans for converting countries responsible for 99 percent of carbon emissions to 100 percent wind, water and solar power for all energy purposes. The study, published online as the inaugural paper in the new scientific journal Joule, shows how ambitious action could meet all transportation, electric power, industry, and heating or cooling needs. It breaks out details such as the number of roof-mounted solar panels needed, the number of new permanent jobs created, land and ocean area required and pollution-related deaths avoided in such a shift.

All electric

The roadmap requires rapid technology transition. It assumes that electricity will replace all nonrenewable energy sources like coal, oil, and gas, and that electricity will be provided with 100-percent clean, renewable wind, water and solar power. For example, all vehicles will run on battery-electric power. Airplanes, ships and heavy trucks will be electric for short distances and hybrid electric-hydrogen fuel cell for long distance. Home heating and air conditioning will be provided by electric heat pumps. High-temperature industrial processes will be powered by existing-technology electric devices. Stoves will be electric induction.

Jacobson and coworkers found that by electrifying and providing the electricity with renewable energy, power requirements would decrease by about 42.5 percent, with about 23 percent due to the efficiency of electricity over combustion, about 12.5 percent due to eliminating the energy needed to mine, transport and refine fossil fuels, and about 7 percent due to additional efficiency improvements and reductions in energy use.

Grid stability is a serious challenge, but a separate study shows how it could be maintained, despite fluctuating levels of energy being produced by wind or solar, by combining efficient electricity transmission and low-cost storage of heat, cold electricity and hydrogen.

Jacobson has spearheaded similar plans for individual U.S. states and the U.S. as a whole. In each case, he has shown it is technically and economically feasible to convert all-purpose energy infrastructure to clean, renewable energy. The barriers are substantial, but they are mainly social and political, rather than technological, Jacobson said.

“We strive to reduce energy costs, create jobs, stabilize energy prices, eliminate air pollution health problems and eliminate global warming simultaneously,” Jacobson said. “You don’t need to believe in global warming to believe in 100 percent clean, renewable energy, which has so many additional benefits.”

If the plan were fully deployed, 57.6 percent of the world’s energy for all purposes would come from solar, 37.1 percent from wind and the remainder from a combination of hydroelectric, geothermal, tidal and wave energy.

“It is likely that no other energy options can provide such enormous global social benefits,” said study co-author Mark Delucchi, a research scientist at the University of California, Berkeley Institute of Transportation Studies.

The roadmaps include no nuclear power, coal, natural gas or biofuels. Even though some of these fuels have been discussed as part of a decarbonized future, Jacobson and colleagues consider them more expensive, more polluting, more risky or more difficult to install than wind, water and solar. No new hydroelectric dams are proposed – only the more efficient use of existing ones.

The upfront cost of the changes worldwide would be significant – about $124.7 trillion. However, because wind and sunlight are free, the overall cost spread over time, including for operation, maintenance, transmission and storage, would be roughly equal to the direct price of the fossil fuel infrastructure. Overall, the cost of the clean energy system would be much less because it eliminates hidden health and climate costs of fossil fuels.

Additionally, the authors argue that switching to all renewable energy could lessen conflict by creating energy independence, reduce power disruptions and increase access to energy by decentralizing power.

Barriers to implementation

The Paris agreement has at its core a goal of limiting global warming this century “well below” 2 degrees Celsius above pre-industrial levels, pursuing efforts to bring that threshold down to 1.5 degrees Celsius. “Despite laudable goals of the Paris agreement, goals do not provide solutions,” the study’s authors write.

Jacobson believes that implementing the roadmaps is possible only with massive public action around the world. People will need to select leaders who will implement strong policies, reduce barriers and confront entrenched interests, he said. At the same time, consumers will need to transition their own homes and lives, which is increasingly possible given the existence of many low-cost electric technologies (such as heat pumps for air and water heating and air conditioning, induction cooktop stoves, electric cars, batteries, LED lightbulbs and efficient windows) and clean, renewable power. Jacobson recently constructed his own home with the kinds of existing clean technologies he thinks would be necessary to achieve his roadmaps' goals.

While the path to 100-percent renewable energy for the world may seem daunting, early signs of success stories are already emerging. More than 40 countries are at least 5 percent of the way to the 100-percent goal already, according to the study. Of those countries, more than half are at least 10 percent of the way to the goal. Tajikistan leads the way, due to substantial hydroelectric capacity already installed there. China comes in 39th and the U.S. comes in 52nd out of 139 countries analyzed. In addition, over 95 international companies and over 30 cities have committed to 100-percent clean, renewable energy in one or more energy sectors.

The scientific community is in wide agreement that solving the climate challenge requires a massive electrification of the energy sector and a rapid transition away from traditional fossil fuels. Details of the transition pathway are uncertain. The present study shows one possible end point of a transition for each country. The authors acknowledge that others may have competing visions using some energy sources not included in the wind, water and solar portfolio. The authors further stress that multiple clean, renewable energy solutions exist, and as the penetration of renewables increases toward 100-percent, it is likely that adjustments will be needed from any original plan to ensure a reliable energy supply at the end of the transition.

Watch video about timeline for transition to all clean, renewable energy.

Read about wind, water and solar power technologies and efficiency measures for home and business.

Read summary of benefits of 139 countries switching to 100% renewable energy by 2050.

Read more about a transition to 100-percent clean, renewable energy.

Jacobson is director of Stanford’s Atmosphere/Energy Program and a senior fellow at the Precourt Institute for Energy and the Stanford Woods Institute for the Environment.

Co-authors of “100% Clean and Renewable Wind, Water, and Sunlight (WWS) All-Sector Energy Roadmaps for 139 Countries of the World” include Mark A. Delucchi of the University of California, Berkeley; Liat Chobadi of Technical University of Berlin, Germany; P. Enevoldsen of Aarhus University, Denmark; and Zack A. F. Bauer, Savannah C. Goodman, William E. Chapman, Mary A. Cameron, Cedric Bozonnat, Hailey A. Clonts, Jenny R. Erwin, Simone N. Fobi, Owen K. Goldstrom, Eleanor M. Hennessy, Jingyi Liu, Jonathan Lo, Clayton B. Meyer, Sean B. Morris, Kevin R. Moy, Patrick L. O’Neill, Ivalin Petkov, Stephanie Redfern, Robin Schucker, Michael A. Sontag, Jingfan Wang, Eric Weiner and Alexander S. Yachanin – students in the Atmosphere/Energy Program in Stanford’s Department of Civil and Environmental Engineering.

The nonprofit Solutions Project provided partial funding for three student researchers.