Heavy winds and plenty of sun coupled with inflexible consumption pushed German wholesale power prices into negative territory for several periods in February this year, triggering a rule in renewables legislation that blocks support payments to offshore wind operators.

According to the so-called “six-hour rule” introduced in a reform of Germany’s Renewable Energies Act (EEG), operators of offshore wind farms commissioned from 2016 on won’t receive feed-in tariffs or market premia they are otherwise entitled to for all periods in which power prices on wholesale spot markets have been in negative territory for six hours or more.