The Mexican renewable energy sector is celebrating an early court victory in its fight against retroactive changes that it warned could “destroy” project values and undermine confidence.

A federal judge backed an injunction seeking to halt rule changes over tradable Clean Energy Certificates (CELs) that power users buy to help meet renewable share mandates, said local reports shared on the website of Mexican wind power association Amdee.

Even if appealed by the government, the court’s decision will ensure the existing arrangements for CELs persist for months to come, according to the reports.

Amdee and its solar counterpart AsolMex are opposing the changes, which they claim would send the value of the certificates plunging, retroactively undermining the economics of projects. Global giants Enel and EDF are said to be parties to legal moves, but have previously declined to comment.

Opponents fear the planned changes would also threaten the spectacular price falls that drove Mexican renewable power below $21/MWh.

Mexico’s previously buoyant renewable energy sector has been in turmoil since, without any warning, centre-left president André Manuel Lopez Obrador (AMLO), scrapped government tenders soon after taking power in late 2018.

The move came despite the success of a rolling series of tenders which had contracted 7GW of solar and wind at steadily declining prices.