Bulgaria's batteries passed 6 GW and started charging at night

Three things between 29 October and 4 November changed what a flexible asset is worth and what it has to accept to get connected. Bulgaria's battery fleet passed 6.23 GW and moved its charging into the night as the solar day shortens, Denmark's transmission operator asked the market what it thinks of connections that can be curtailed, and four operating British batteries changed hands on the strength of what more hours might add. In each case the money depends less on how big the asset is than on when it runs and on the terms of its connection.

Bulgaria's operating battery power reached 6.23 GW in late October

Battery energy storage in Bulgaria has outrun even the country's solar build. Operating power online reached 6.23 GW late in October, against 3.43 GW before the end of May, on an update from the Electricity System Operator reported by Capital and carried by Balkan Green Energy News on 3 November. The fleet can store more than 19 GWh, an average duration above three hours, which means four-hour systems are the ones being installed and at least one five-hour project has been reported. Solar capacity stands at 7.3 GW, so battery power now equals about 85% of it.

The comparison that travels further is with load. At the end of October, two years after the first Bulgarian systems came on stream, battery power covered 85% of the country's peak electricity load. The same measure gives Texas 17%, Great Britain 17%, Australia 23% and California 33%. Between 1 and 25 October the fleet supplied 18 GWh a day and absorbed 19.9 GWh, and as photovoltaic output turned erratic with the approach of winter, charging shifted into the night. State support programmes have run their course, so what is being built now is commercial, and it is arriving in a market that is already much fuller than the one the first projects were underwritten against.

What that does to prices is visible from outside. Eurelectric's Power Barometer, published on 30 September, found that Bulgarian wholesale power moved from 21% above the EU average in 2024 to 8.3% above it in 2026, which it attributes to leaning less on expensive fossil generation at peak. The same report put EU utility-scale storage at 64 GW in 2025 with 78 GW of additions planned, well short of the 200 GW the bloc has set for 2030. Bulgarian wholesale power is still expensive by European standards, along with most of south-eastern Europe and Hungary, but the peaks and the daily spreads are measurably milder than they were. One reactor at Kozloduy has been out for maintenance since 8 October and is due back late in November, and Romania's Cernavoda has been offline since August, so part of this autumn's price shape is borrowed.

For anyone underwriting a battery, Bulgaria is the clearest picture yet of what the end of a build-out looks like. The single wide evening spread that paid for the first wave thins as the fleet fills in behind it, and the earnings move to whoever can follow the shape of the day: charging overnight in winter rather than at midday, holding capability back for the hours that still pay, and selling into more than one product. The assumption to test is how accurately the asset can place its megawatt-hours in a system where several gigawatts of batteries are trying to do the same thing at the same moment, which matters more at this point than how much it can store.

Fusebox runs real-time monitoring and dispatch through automated control loops that act on forecasts, prices and constraints rather than on a schedule fixed in advance. When the spread thins, placing megawatt-hours in the hours that still pay is the whole job, and that is the decision the loop makes.

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Denmark offered producers curtailment in exchange for a cheaper, faster connection

Danish grid capacity is now rationed by law, and storage sits in the third of four categories. Energinet said on 21 October that several hundred applicants would hear in November whether they can connect, under the four priority categories adopted in the political emergency plan for the grid. Households, smaller businesses and critical functions in category 1, and most mature, connection-ready consumption projects in category 2, get their answers in the first half of the month. Energy storage and the other large projects, categories 3 and 4, are answered later in November, and the operator has already said that full grid access for those two categories looks difficult. Between 2020 and 2025 Denmark connected 3.8 GW of consumption and 6.2 GW of production, against a national peak of about 7 GW.

The way out it is building is a connection that is deliberately less than firm. On 2 November Energinet put two products for permanent limited grid access for producers into public consultation, opened on 30 October and running to 13 November at 12:00, with a webinar on 6 November. The bargain is explicit. A producer accepts that its feed-in can be limited when the transmission grid runs short of capacity, and in exchange it avoids the connection payment that full grid access normally carries. Signing such an agreement also counts as a demonstration of grid-friendliness, which lifts a project up the pooled queue and can bring the connection date forward. One product covers producers on the transmission grid, the other producers on the distribution grid, and the second works whether the site holds full or limited access locally. Energinet names solar, wind and batteries in the feed-in direction as the obvious candidates. It follows the first product of the family, permanent limited access for consumption, notified to the regulator on 9 October, and three more are being drafted.

The trade association TEKNIQ, which welcomed the move from a connection freeze to active capacity management on 22 October, put the condition on it that asset owners will recognise. Companies need to know how often their capacity can be limited, what minimum they can count on, and when the grid behind them is actually reinforced. Flexibility, as its sustainability chief Troels Hartung put it, must not simply move the risk onto the customer.

If you own or finance assets in a congested area, this is the question to model before the consultation closes. A curtailable connection is worth having when you can price the hours you expect to lose and still clear your return, and it is worth refusing when you cannot. That calculation needs a view of which hours the grid is likely to be short in, what your asset earns in them, and what the same asset can earn elsewhere in the stack while the feed-in side is capped. For a battery the answer is rarely symmetrical, because the charging direction and the discharging direction do not meet the same constraint at the same time. If you want to explore the question before you put a number on it, the Fusie knowledge bot is open, and we are happy to go through a specific site with you.

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Econergy bought four British batteries that run for one hour

At the other end of an asset's life, the secondary market is pricing operating batteries on what they could become. Econergy disclosed in a Tel Aviv Stock Exchange filing, reported on 4 November, that it had acquired 100% of the shares in the holding company of four operational standalone batteries in England, totalling 106 MW. All four run at one-hour duration, 106 MWh in total, and the buyer is evaluating augmentation to three hours, which would take them to roughly 318 MWh. The seller was not named and transfer filings had not reached Companies House at the time of reporting.

The numbers around the deal say what the thesis is. The portfolio is expected to generate about GBP 4.7 million of EBITDA in 2027 before any augmentation, and the purchase takes Econergy from two to six grid-connected British assets and from 90 MW to 196 MW of operational capacity, alongside a 1.6 GW UK development pipeline and a European portfolio of 5.9 GW, of which 3.3 GW is expected to be connected, under construction or pre-construction by 2028. The company frames the extra hours as the route to capturing more value by shifting energy from periods of strong renewable output into periods of stronger demand.

For owners of short-duration assets, the read is practical. A one-hour battery with a connection, a grid agreement and a trading history is now a platform that someone else will pay for and lengthen, which gives a floor to assets that look stranded on their original revenue model. It also sets the diligence question for anyone selling: what the site can earn today under active dispatch, and what the same connection would carry with more megawatt-hours behind it. Those are two different models, and the gap between them is where the price is argued.

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Watch list

• Energinet's consultation on the two limited-access products for producers closes on 13 November at 12:00, with a webinar on 6 November, after which the products go to the regulator for approval.
• Energinet answers category 3 and 4 applicants later in November, the first real test of what storage is offered in a rationed Danish grid.
• Germany's EEG 2027 readings: the renewable energy federation expects the Bundestag between 9 and 13 November and the Bundesrat on 20 November, with state-aid clearance for the present law expiring on 31 December and an alternative to direct marketing for small rooftop systems still under negotiation.
• Whether Econergy proceeds with augmentation of the four English sites to three hours, and on what timetable.
• The Kozloduy unit due back from maintenance late in November, and what returning baseload does to Bulgarian evening prices and to the spreads the new commercial projects are counting on.