In its 'New Energy Outlook 2017' report, BNEF said wind and solar projects will account for nearly half of the total installed capacity and produce 34% of global power generation by 2040.
This compares with just 12% of total installed capacity and 5% of generation in 2016.
"Installed solar capacity increases 14-fold and wind capacity fourfold by 2040. We anticipate renewable energy reaching 74% penetration in Germany, 38% in the U.S., 55% in China and 49% in India by 2040 as batteries and new sources of flexibility bolster the reach of renewables," BNEF said in its report.
Costs of renewables are also set to fall, with a predicted 74% drop in offshore wind prices, BNEF said, compared with 47% for onshore and 66% for solar.
The analysis firm said "development experience, competition and reduced risk, and economies of scale" would help to drastically cut offshore wind costs by 2040.