Falling oil prices have led to questions about the attraction of renewable energy in the face of more affordable oil, but private equity firms remain bullish about the sector’s prospects.

Portuguese buyout firm Magnum Capital Industrial Partners agreed the biggest renewable energy deal in the past 13 years last week, with a €1.2bn ($1.5bn) acquisition of wind energy assets owned by Enersis, a portfolio company of Australian investment bank and infrastructure specialist Babcock & Brown.