Nearly half of the world’s electricity is set to be powered by renewable energy by 2030, according to forecasts, but the landmark would still miss global targets.

The world is on course to add the equivalent power capacity of China, the European Union, India and the US combined, about 5,500 gigawatts (GW), via renewables, the International Energy Agency said.

However, the massive forecast ramp-up of solar panels, wind turbines and other green power sources will still miss a goal set last December by the UN of tripling global renewable capacity by the end of the decade.

Fatih Birol, the IEA’s executive director, said the growth in renewables was not just being driven by efforts to cut emissions, but by the fact that they offer “the cheapest option to add new power plants in almost all countries around the world”.

As a result, renewables growth is “moving faster than national governments can set targets for”, he said.

Nonetheless, if countries are going to hit the target of tripling global renewables capacity, Governments need to ramp up efforts to join green power sources to their power grids.

This would mean building or upgrading 25 million kilometres of pylons, cables and other grid connections over the coming years.

About 10% of renewable electricity generation is not put to use because of grid constraints in several countries, the IEA said, meaning countries must make a concerted push on upgrading their infrastructure.

The agency also said the world needs 1,500 GW of storage capacity by 2030, to help address the challenge.

Erebus project
A floating offshore wind turbine off Kincardine in Scotland (Blue Gem Wind/PA)

China is set to account for nearly 60% of renewable capacity installed worldwide over the next six years, bringing the country to almost half of the total capacity by the end of the decade.

It comes as the UK Government pushes on with a swathe of policies designed to ramp up capacity domestically, including launching a state-owned energy investment firm, GB Energy, which is set to boost offshore wind power.

And on Wednesday, a joint task force between officials and representatives from companies forecast that floating wind turbines – currently a relatively nascent technology – could provide one third of the UK’s total offshore wind capacity by 2050.

The report said the floating wind industry could employ 97,000 people by 2050 and contribute £47 billion to the economy.

Floating projects are currently expensive to build, but this could fall by 30% over the next six years to become more affordable.

Energy Secretary Ed Miliband said: “By leading the world in this cutting-edge technology, we can speed up the transition to clean energy and secure good jobs and economic growth for our industrial heartlands – all while ensuring the expertise of our North Sea workforce are the people who power this clean future.”

The taskforce’s co-chair, Dan McGrail, added that floating wind is “set to become one of the biggest global industries of the twenty-first century, and the UK now has an unprecedented opportunity to seize the lead by scaling up this innovative technology”.