Reaching the goal of getting 100 percent of the world's energy from renewable resources is technically and economically feasible today.
...all the studies agree that there are no technical barriers to getting 100 percent of our energy from renewable resources. Their technical potential, he said, “far exceeds even our wildest future (demand) projections.”
Global energy use would also decline sharply. Just by replacing the fuels in the global energy mix with electricity, Jacobson found that total energy demand would decline 32 percent by 2030, even without accounting for energy efficiency measures that would also be adopted.
In the U.S., the study found that a similar shift to electricity and electrolytic hydrogen would cut primary energy demand by 37 percent, also before other efficiency measures. The switch would reduce California’s energy demand by 44 percent, largely as a result of converting the transportation sector to more efficient electric propulsion.