Global renewable energy giant EDPR said it will sue the governments of Poland and Romania over windfall taxes on green power generation that could cost it €300m ($320m) in “unreasonable payments”.

EDPR’s parent group, Portuguese utility EDP, told investors it will “pursue all legal actions” over the way emergency measures have been applied in the two eastern European countries, claiming they breach a principle set out by the EU that so-called clawback mechanisms should only apply to revenues that power producers have made, not those subject to financial hedging that means no windfall accrues to the generator in practice.