Sold on completion, paid on access: 3 shifts in what a European battery is worth

Between 22 and 28 October, three stories priced the same thing from different angles: what a finished battery is actually worth. In Poland, a sale of two completed projects put 80 million euros of the price on whether they are cleared into balancing markets. Portugal wrote stability duties into its connection rules, and the Czech ministry pushed two capacity auctions into 2027, which moves the date the capacity money starts.

1. A Polish battery sale left 80 million euros hanging on market access

Greenvolt Power has agreed to sell two completed Polish batteries, the 200 MW/800 MWh systems at Ełk and Turośń Kościelna, to the Malta-based investor A&R Investments. The deal was announced on 23 October and closes by the end of the year, and both projects were finished in the third quarter with the permits needed to operate (Energy-Storage.news). The structure is the part worth reading twice. ESS News reports a potential value of 391.5 million euros, of which 311.5 million is payable at closing and 80 million is contingent on the projects being approved to participate in grid-balancing markets. Both assets already carry 17-year capacity market contracts starting in 2028, which pay a fixed amount for making 85% of rated capacity available to the Polish system, plus ten-year tolling agreements that hand optimisation and trading to someone else. Around a fifth of the headline price still sits behind a prequalification gate.

The same week showed how quickly the Polish fleet is turning over. Greenvolt has now sold four of its five Polish projects, a portfolio of 1.3 GW/5.2 GWh. State-controlled PGE broke ground on the 400 MW/800 MWh Gryfino project, a 1.14 billion zloty investment using Fluence Smartstack blocks and due online in 2028. Tauron bought the 28.27 MW/120 MWh BME Jawor project, which has a capacity contract starting in 2029, and Tavion started building a 20 MW/40 MWh site in Bydgoszcz for the second quarter of 2027. In Germany, Giga Storage closed 260 million euros of debt from seven banks for the 350 MW/1.4 GWh Albatross project in Lower Saxony and signed a grid connection agreement with Amprion on 14 October, which Amprion says is its first for a large-scale battery (ESS News). It connects straight into the 380 kV grid at Merzen, starts construction in early 2027 and now commissions in early 2029, a year later than the date it carried when it reached ready-to-build earlier this month.

Put together, the week says that the thing being bought is proven availability. A capacity contract sets the floor. A connection agreement sets the physical ceiling. The value in between is the ability to sell into energy and balancing markets, and this deal attached a number to it.

If you own or manage BESS, this is the week to stop treating prequalification as an operations chore. First, give it an owner and a date inside the build programme, and put the same date in the financing or sale documents, because a buyer will. Second, check what each asset can actually deliver against the TSO tests as they stand today, before delivery obligations under a capacity contract start running. Third, assume the capacity payment is the floor and design the energy and balancing layers on top of it rather than after it.

That middle layer is what we run. Fusebox integrates and dispatches BESS, PV, EV chargers, HVAC systems and C&I industrial loads in a single platform, and we operate across 15 European markets and 9 TSOs. A finished asset with no route into the market earns the floor and nothing else.

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2. Portugal now expects big batteries to hold the grid up, not just trade on it

New battery plants connected to Portugal's transmission grid, or rated at 45 MW or more, must provide grid-forming capability and synthetic inertia under an ordinance that took effect on 23 October and applies to connection requests filed from that date (ESS News, Diário da República). Existing plants are caught only if they go through a significant expansion, modernisation or equipment replacement. The grid-forming duty also covers plants connected at 110 kV and above on terms the grid operators will set, and reaches down to the 10 MW to 45 MW class, where the technical annex ties it to the project's grid capacity title, permit or tender documents.

The smaller thresholds matter more than the headline. Plants of 500 kW or more must switch automatically from charging to discharging when frequency falls, with a default underfrequency relay setting of 49.2 Hz while charging. Everything above 1 MW has to be technically capable of frequency containment and restoration reserves and of voltage and reactive power control, and has to give the system operator real-time monitoring and remote control. The inertia parameters come from a joint report by ENTSO-E, the EU DSO Entity, SolarPower Europe, WindEurope, Energy Storage Europe and CENELEC: synthetic inertia across frequency deviations between 47.0 Hz and 52.5 Hz and rates of change up to 2 Hz per second, a mechanical starting time adjustable from 1 to 20 seconds with a default of 12, and a damping ratio of at least 10% for oscillations between 0.1 Hz and 10 Hz. Pumped hydro and other storage that provides synchronous inertia is excluded. Lisbon says it is setting the requirements now because of the storage growth it expects, while the EU generator connection code is still being revised, and that the ordinance does not stop the revised EU rules being implemented later.

For anyone specifying a battery or a hybrid for Iberia, this is a procurement decision, not a compliance footnote. Grid-forming inverters, inertia headroom, automatic underfrequency response and remote control are now part of the connection, which means part of the capex and part of the bid. Ask the awkward question early: who holds the control interface, and can it carry stability duties and market dispatch at the same time? One control layer doing both is cheaper than a second one bolted on in year three.

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3. Czechia moved two capacity auctions into 2027, and comments close on Friday

The Czech Ministry of Industry and Trade has published a draft amendment to the general measure that introduced the country's capacity mechanism in August, and it moves the two extraordinary supplementary auctions, held four and five years before delivery, from 2026 to 2027 (ESS News). The draft touches 20 provisions of the original measure. It clarifies how the preliminary assessment can be extended, lets capacity eligible for 15-year contracts compete in several auctions at once, and changes how the demand curve is built (oEnergetice, which reports the draft was published on 15 October). Comments can be submitted until 30 October. Transmission operator ČEPS had already moved the preliminary assessment deadline for the first three auctions from 20 September to 18 November at the ministry's request, citing conditions in the equipment market and supply chains and the aim of widening competition.

The mechanism is not a small one. The European Commission approved it on 16 July for ten years, with an estimated budget of 3.1 billion to 6.2 billion euros financed through consumer charges, individual contracts of up to 15 years, and eligibility for existing and new generation, storage, cross-border capacity and demand-side response. The first delivery period runs from 1 November 2030 to 31 October 2031. So the money is real, and it is late. Czechia connected 318 MWh of batteries in the first half of 2026, against 174 MWh a year earlier, and none of that fleet can wait four years to be paid.

Two things follow for developers and for C&I sites with flexible load in Czechia. The consultation closes in two days and demand response is eligible, so the participation rules and the demand curve are worth reading properly rather than skimming. And whatever clears, delivery starts in November 2030, which means every project in between earns from energy, balancing and congestion markets or it does not earn at all. Build that stack first. Treat the capacity contract as the layer on top. If you want to poke at the detail before you talk to a human, our knowledge bot is open.

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Regulatory and market watch

• EU energy ministers meet in Luxembourg on 29 October for a policy debate on the network charges regulation, which amends the electricity market regulation, plus exchanges of views on winter 2026/27 energy security and post-2030 targets (Council of the EU).
• Czechia: comments on the capacity mechanism amendment close 30 October, and the ČEPS preliminary assessment for the first three auctions now closes 18 November (oEnergetice).
• Portugal: the grid-forming, inertia and remote-control duties apply to connection requests filed from 23 October, and to existing plants that undergo a significant expansion, modernisation or equipment replacement (ESS News).
• Great Britain: limited-duration assets in the Balancing Mechanism must comply with Grid Code modification GC0166, which adds Maximum Delivery Offer, Maximum Delivery Bid and Future State of Energy parameters, by 5 November (NESO).
• Great Britain: NESO's winter period opens on 31 October and runs to 31 March, with a forecast operational surplus of 5.9 GW, a 9.5% buffer over peak demand (Solar Power Portal).