A BNEF report released this week says significant cost cuts in wind, solar and battery storage can help increase the contribution of renewables to global grid power to nearly 50% by the middle of the century, with total worldwide electricity demand expected to increase by 62% in this time.

"Our power system analysis reinforces a key message from previous New Energy Outlooks - that solar photovoltaic modules, wind turbines and lithium-ion batteries are set to continue on aggressive cost reduction curves, of 28%, 14% and 18% respectively for every doubling in global installed capacity," said New Energy Finance lead analyst, Matthias Kimmel.

"By 2030, the energy generated or stored and dispatched by these three technologies will undercut electricity generated by existing coal and gas plants almost everywhere."

The report suggests coal's place in the global power mix will decline, from providing 37% of electricity today to 12% by 2050. Oil's role as a power-generating source could become almost non-existent.