Record solar energy production in Romania drives electricity prices into negative territory.

Romania's commercial solar power generation reached a new peak around noon on Friday, supplying roughly one-third of the immediate demand and causing electricity prices in the day-ahead market to briefly dip into negative values for the first time this year. However, these high solar output levels were not sustained for the entire day due to the shorter duration of winter days.

As reported by Romanian media and data from the transmission system operator Transelectrica, commercial solar output, excluding prosumers, peaked at 2,048 MW on Friday at 11:39 a.m., while demand was slightly over 6,000 MW. The previous record was 1,866 MW, set on June 16, 2025, at 12:33 p.m.

While solar production tends to be higher in summer, sunny winter days can provide excellent conditions for photovoltaic generation, as the panels do not suffer efficiency losses due to overheating, and snow can reflect additional light.

Transelectrica's figures did not include prosumers, but estimates suggest their inclusion would have raised the total output to around 4,000 MW, according to Profit.ro.

If prosumers were factored in, solar energy would have met approximately two-thirds of the total demand.

By the end of November 2025, Romania had nearly 290,000 prosumers with a combined capacity of 3.35 GW, according to the Romanian Energy Regulatory Authority (ANRE). The Romanian Photovoltaic Industry Association (RPIA) noted that the country’s total solar power capacity surpassed 7 GW in 2025.

At the time solar production hit the 2,048 MW record, electricity generation from nuclear and fossil fuels was around 1,300 MW.

On Romania’s day-ahead market, three hourly intervals with negative prices were noted on Saturday, marking the first occurrence of such prices this year.

The ongoing increase in installed renewable capacity is expected to result in more instances of negative pricing in the future.