Bulgarian Reactor Operator Extends 140 MW Output Curb to Tuesday
Bulgaria's reactor restriction prolongs a summer of drought-driven nuclear losses that have stripped more than 40% of southeast Europe's nuclear generating capacity.
The operator of a Bulgarian nuclear reactor extended a 140 MW output restriction through Tuesday (2026-08-25), Montel reported on Friday (2026-08-21), prolonging curtailed generation into the final week of August as southeast Europe's power system absorbs one of its heaviest nuclear outage periods in recent years.5
The extension compounds a sequence of decisions that have stripped more than two-fifths of the region's nuclear capacity from full service. Romania's operator Nuclearelectric shuttered the country's only remaining operating nuclear reactor on Thursday (2026-08-13), OilPrice.com reported, after the Danube fell to a 90-year low, making normal cooling operations untenable. No restoration timeline was given.4
Slovenia's 700 MW Krsko plant had already moved to reduce output. Operator Nek announced on Wednesday (2026-08-05) that it would cut to 80% of capacity from Thursday (2026-07-30) night, pushing southeast Europe's aggregate nuclear curbs from 40% to 42% of regional capacity, Montel reported. Romania's full closure and Bulgaria's ongoing 140 MW restriction represent further capacity losses on top of that figure.2
Forty-two percent of regional nuclear capacity under restriction during peak summer demand is a significant baseload shortfall. The same heat that suppresses river levels drives residential and commercial electricity consumption higher, compressing supply and amplifying demand simultaneously.3,2
There is little reason to expect rapid relief. Depleted water resources across the region could keep southeast Europe's power system under pressure until October, a Montel EQ analyst warned on Tuesday (2026-08-11), even as some heatwave-driven curbs eased slightly in mid-August after overnight temperatures fell. River systems do not recover on the timescale of individual operator decisions. Rainfall deficits accumulated over weeks take weeks to unwind, and the Danube basin was already well below normal before August's sharpest heat arrived.3
The broader European market reflects summer tightness rather than the Bulgarian announcement alone. ICE Endex TTF front-month gas settled at €65.83/MWh at Friday's close (2026-08-21), with the THE M+1 contract at €66.49/MWh the same session. German front-month baseload power closed at €135.17/MWh on Friday (2026-08-21). Sustained nuclear losses across southeast Europe contribute to the tightness these prices embed by extending how long gas-fired generation must compensate.3,5
When nuclear baseload output falls across multiple systems simultaneously, gas-fired generation carries a heavier share of the load. The Romanian shutdown and Bulgaria's 140 MW curb, running in parallel through at least Tuesday (2026-08-25), extend that pressure on thermal generation and, by extension, on European gas supply already competing with storage fill ahead of winter.3,4,5
Bulgaria has expanded its storage infrastructure in 2026. Sungrow and Sunotec commissioned a 150 MW, 600 MWh battery project in Nova Zagora in June 2026 for independent power producer Enery, with the partners expecting to bring a total of 2.2 GWh of battery storage capacity online in Bulgaria over the following two months, Power Technology reported. That capacity provides intraday balancing but is not a substitute for a multi-day nuclear deficit running at 140 MW.1
The operator has not publicly indicated whether Tuesday (2026-08-25) ends the restriction or triggers another extension decision. Romania's Nuclearelectric offered no return-to-service date when its shutdown was reported. With analysts pointing to October as the horizon for regional power stress, the pace of Danube recovery over the coming weeks will carry more weight than any single operator announcement.4,3,5