Renewable energy moved past coal in 2015 to become the biggest source of global electricity capacity, the International Energy Agency (IEA) said on Tuesday.
Last year "marked a turning point for renewables" the body said, with clean sources of energy representing over 50 percent of the planet's new power capacity, hitting 153 gigawatts, a 15 percent increase in electricity capacity on the year before.
The IEA said that in 2015 around 500,000 solar panels were installed every day, while in China – which was responsible for 40 percent of all increases in renewable capacity – two wind turbines were installed every hour.
In its latest renewables forecast, the IEA said that the next five years would see this growth continue, with 30,000 solar panels and 2.5 wind turbines installed per hour. Renewables would see their share of electricity generation grow from 23 percent in 2015 to 28 percent in 2021.
"We are witnessing a transformation of global power markets led by renewables and, as is the case with other fields, the center of gravity for renewable growth is moving to emerging markets," Fatih Birol, executive director of the IEA, said in a news release.
The IEA added that renewables were expected to meet over 60 percent of global power capacity growth in the next five years, exceeding 7,600 terawatt hours in 2021.
Technological developments, extra competition and better policy support in key markets were seen as the key drivers behind renewables' growth. Climate change was another factor, as well as the desire of governments to slash dangerous air pollution and improve energy security.
Despite 2015 being an "exceptional" year, the IEA noted that there were still grounds for caution, with uncertainty surrounding policy in a host of countries "slowing down the pace of investments." Among other things, the rapid growth of wind and solar photovoltaic technologies had led to issues with system integration, while costs were still an issue for developing nations.
"I am pleased to see that last year was one of records for renewables and that our projections for growth over the next five years are more optimistic," Birol went on to add.
"However, even these higher expectations remain modest compared with the huge untapped potential of renewables. The IEA will be working with governments around the world to maximize the deployment of renewables in coming years."