Though the feasibility of a 100 percent renewable energy grid is a hotly debated topic in the U.S., it is already coming to fruition in many countries, according to Renew Economy. Iceland and Paraguay have already achieved 100 percent, powered mostly by hydropower, wind, geothermal, and solar energy, while Costa Rica (99), Norway (98.5), Austria (80), Brazil (75), and Denmark (69.4) are not far behind. The US is at 14.3 percent renewables.
Many other large regions are thriving off 100 percent renewable energy, including Germany’s Mecklenburg-Vorpommern and Schleswig-Hostein regions, New Zealand’s South Island, and Denmark’s Samsø Island, and Quebec and British Columbia are getting close. Last summer, in order to demonstrate the practicality of future reliance on renewables instead of fossil fuels, the Qinghai Province in China relied solely on wind, solar, and hydro power sources for a straight seven days.
Bloomberg New Energy Finance (BNEF) has estimated that Germany’s grid will see nearly 75 percent renewable penetration, Mexico will be over 80 percent, and Brazil and Italy will be over 95 percent by 2040, and that’s without taking into account the influence of the Paris Climate Accord.
Indonesia has well over the necessary amount of pumped hydro storage sites to support a 100 percent renewable electricity grid, and storage is an essential factor in moving towards wind and solar reliance as it ensures that regions will still be powered on cloudy days with no wind.
Hydro pumping is the most popular renewable energy storage system worldwide, a process that is made possible by pumping water from a reservoir at a lower level to one at a higher level when there is excess electricity or when electricity can be generated at a low cost. When there is high demand for energy, the water in the upper reservoir is run through the hydroelectric plant’s turbines, which immediately produces energy. By 2050, “pumped storage hydropower capacities would be multiplied by a factor of 3 to 5,” according to the International Energy Agency’s 2012 Technology Roadmap: Hydropower.
The U.S. Department of Energy estimates that “domestic hydropower could grow from 101 gigawatts to nearly 150 gigawatts of combined electricity generation and storage capacity by 2050,” and hydro energy storage is just one way for the U.S. to integrate renewables into future grids. NOAA researchers projected in 2016 that just with improvements to existing infrastructure, “the United States could slash greenhouse gas emissions from power production by up to 78 percent below 1990 levels within 15 years while meeting increased demand.”