Bulgaria's Constitutional Court on Thursday revoked the 20% fee levied on the income of photovoltaic plants and wind farms that has spooked investors.

The fee was introduced by the outgoing socialist-liberal government at the beginning of the year to rein in a rise in electricity costs prompted by the rapid expansion of the share of the more expensive solar and wind energy in the electricity mix during the period 2011-2012.

According to Bulgaria's State Commission for Energy and Water Regulation (DKEVR), the new fee has generated receipts of BGN 36 M by the end of March.

In January, Bulgaria’s President Rosen Plevneliev asked the country’s top court to scrap the fee as unconstitutional as it only applied to photovoltaic plants and wind farms but not to biomass, hydroelectric or co-generation power plants. Ten out of the 12 Constitutional Court judges have backed the scrapping of the fee, the Bulgarian National Radio said.

The Bulgarian Photovoltaic Association (BPVA) welcomed the court’s decision. Its Chair Meglena Rusenova said the ruling restores the rule of law and will stabilize Bulgaria’s energy sector.

”The Constitutional Court sends a strong signal from Bulgaria to all foreign investors that Bulgaria already is a stable destination for their investments and the Constitutional Court safeguards the stability of the investment environment in the country,” Rusenova said.

The Constitutional Court’s decisions have no retroactive force and the sums collected so far will not be restored to the solar and wind energy producers.