Need to make renewable energy system more sustainable: IEA

New Delhi: Countries have to work towards making their renewable energy system more secure and sustainable, even as their governments need to remove this concern that clean energy sources cannot achieve full potential, says an International Energy Agency (IEA) report.

"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," IEA Executive Director Fatih Birol said.

Releasing the 'Medium-Term Renewable Energy Market Report 2015' in Istanbul, Birol said, renewables are poised to seize the crucial top spot in global power supply growth, but this is hardly time for complacency.

According to IEA annual market report, renewable energy will represent the largest single source of electricity growth over the next five years, driven by falling costs and aggressive expansion in emerging economies.

Pointing to the great promise renewables hold for affordably mitigating climate change and enhancing energy security, the report warns governments to reduce policy uncertainties that are acting as brakes on greater deployment.

It said that renewable electricity additions over the next five years will top 700 gigawatts (GW) ? more than twice Japan's current installed power capacity.

They will account for almost two-thirds of net additions to global power capacity ? that is, the amount of new capacity that is added, minus the scheduled retirements of existing power plants.

Non-hydro sources such as wind and solar photovoltaic panels (solar PV) will represent nearly half of the total global power capacity increase.

The report sees the share of renewable energy in global power generation rising to over 26 percent by 2020 from 22 percent in 2013 ? a remarkable shift in a very limited period of time.

By 2020, the amount of global electricity generation coming from renewable energy will be higher than today's combined electricity demand of China, India and Brazil.

The report says the geography of deployment will increasingly shift to emerging economies and developing countries, which will make up two-thirds of the renewable electricity expansion to 2020.

China alone will account for nearly 40 percent of total renewable power capacity growth and requires almost one-third of new investment to 2020.

The report says that the financing remains key to achieving sustained investment. Besides regulatory barriers, grid constraints, and macroeconomic conditions pose challenges in many emerging economies.