Global capacity is set to rise by 50% in five years' time, driven by solar photovoltaic (PV) installations on homes, buildings and industry, according to the International Energy Agency (IEA).
Total renewable-based power capacity will rise by 1.2 terawatts (TW) by 2024 from 2.5 TW last year, equivalent to the total installed current power capacity of the United States.
Solar PV will account for nearly 60% of this growth and onshore wind 25%, the IEA's annual report on global renewables showed.
The share of renewables in power generation is expected to rise to 30% in 2024 from 26% today.
Falling technology costs and more effective government policies have helped to drive the higher forecasts for renewable capacity deployment since last year's report, the IEA said.
"Renewables are already the world's second-largest source of electricity, but their deployment still needs to accelerate if we are to achieve long-term climate, air quality and energy access goals," said Fatih Birol, the IEA’s executive director.
"As costs continue to fall, we have a growing incentive to ramp up the deployment of solar PV," he added.
The cost of generating electricity from distributed solar PV (PV systems on homes, commercial buildings and industry) is already below retail electricity prices in most countries.
Solar PV generation costs are expected to decline a further 15% to 35% by 2024, making the technology more attractive for adoption, the IEA said.
However, policy and tariff reforms are needed to ensure solar PV growth is sustainable and avoid disruption to electricity markets and higher energy costs, the report said.