The capacity will be more than double what utilities currently generate in Japan. Renewable electricity additions will account for about two-thirds of net additions to worldwide power capacity.
The report revealed that the share of renewable energy in global power generation will increase to more than 26% by 2020 from 22% in 2013.
According to the report, non-hydro sources like wind and solar photovoltaic panels will represent around half of the total global power capacity increase.
Geographically, the IEA expects that in OECD countries about all generation capacity additions will be in the form of renewable sources.
China will be the leading nation in terms of deployment, accounting for 40% of total renewable capacity growth, followed by the EU and the US.
Renewable generation costs have dropped in several parts of the world because of sustained technology progress, enhanced financing conditions and expansion of deployment to newer markets with better resources, the report said.
IEA executive director Fatih Birol said: "Renewables are poised to seize the crucial top spot in global power supply growth, but this is hardly time for complacency.
"Governments must remove the question marks over renewables if these technologies are to achieve their full potential, and put our energy system on a more secure, sustainable path."
