Doubling the share of renewable energy in the global power mix could help save up to $4.2 trillion (£2.9tn) every year by 2030.

A new report from the International Renewable Energy Agency (IRENA) recommends options to boost the share from more than 18% currently to as much as 26% in the next 14 years.

The analysis covers 40 countries which represent around 80% of global energy use.

It suggests “great strides have been made” to use more renewable energy, which is on track to generate roughly 30% of the world’s electricity by 2030. That’s up from 23% today.

However, it believes doubling it would increase the share to more than 50%, with “great potential” in transport, buildings and industry – the three sectors that are currently lagging behind.

The rise would require an average annual investment of $770 billion (£535bn) up to 2030, it adds.

Although achieving that would increase the cost of the global energy system to around $290 billion (£201bn) every year, the report states the savings would be up to 15 times higher than the cost.

That would also help create 24.4 million jobs and reduce air pollution enough to save up to four million lives every year, it adds.

IRENA Director-General Adnan Z. Amin said: “Achieving a doubling is not only feasible, it is cheaper than not doing so. REmap shows this is not only the most economic pathway but also the most socially and environmentally conscious. It would create more jobs, save millions of lives from reduced air pollution and set us on a pathway to limit global temperature rise to two degrees as agreed in Paris.

“For decision makers in the public and private sectors alike, this roadmap sends an alert – both on the opportunities at hand and on the costs of not taking them.”

The World Energy Council today warned of a global water shortfall by 2030 which could severely affect power generation.