Spain will incorporate around 350 MW of batteries during the next five months to close 2026 with an installed capacity close to 650 MW.
The estimate comes from One Hub Energy , which places the current park at approximately 290 MW and detects greater movement in portfolios that are beginning to leave the administrative phase.
“The installation pace is still slow, it’s just getting started, but we are beginning to see several projects entering the construction phase,” says Lluís Millet Biosca , the company’s principal storage consultant, in an interview with Energía Estratégica.
The calendar, however, leaves little room for error.
Construction of a facility can be completed in four or five months, while its commissioning typically takes six or seven. This time lag will be crucial in determining how much power will be available before December.
The mapping carried out by Energía Estratégica on publications in the Official State Gazette identified 969.67 MW of stand-alone and hybrid power systems (BESS) in the permitting process during June. This figure far exceeds the additional 400 MW that One Hub Energy considers necessary to meet its annual forecast.
Among the largest projects are ST Palmosilla, owned by Rolwind Renovables, with 200 MW; Tagus 2 HBESS, owned by Khons Sun Power, with 176.44 MW; Módulos Pacheco, owned by X-Elio Energy, with 105 MW; and BESS Lagerung, linked to A Green Message and Matrix Renewables, with 101.8 MW. The portfolio also includes assets from Abo Wind España, Opdenergy, FRV, and Solaria.
However, the BOE reflects regulatory progress, not immediate construction commitments . In the announcements we see today, projects that reach ready to build (RTB) status will typically begin construction in about 12 months.
Construction capacity would not be the limit.
Millet dismisses the notion that Spain lacks the technical resources to accelerate deployment. The local chain has demonstrated the capacity to install between 6 and 9 GW of photovoltaic capacity annually , despite the fact that solar plants require more complex construction and occupy larger areas.
“The technical capabilities for construction and installation are in place so that, when all the projects reach the ready to build stage, they can be deployed quite quickly,” he says.
The main obstacles arise before construction begins. Urban planning procedures continue to cause delays, and for almost two years now, obtaining new access and connection permits based on priority has become virtually impossible.
Hybrid systems progress more easily from the generation side , but encounter difficulties when they require demand capacity to charge from the grid. Without this authorization, battery operation is restricted to managing the electricity produced by the associated renewable energy plant, and it loses alternative revenue streams.
One Hub Energy's experience reflects the slow pace of development. The company began developing projects for its clients in 2022, and none of these projects have yet reached RTB (Return to Base).
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Many people argue that many of the GW of projects under development may never be built, due to a lack of profitability or because they are merely speculation by developers.
“In general, I don’t think it’s that they will never become operational, but rather that they are slow in the administrative process,” Millet argues.
Development success rates are lower for stand-alone projects, while those linked to solar or wind farms show a more favorable administrative process. Their lower costs and shorter development times reduce exposure during the early stages.
However, hybridization alone does not guarantee viability. Some of these proposals originate as a way to recover photovoltaic assets affected by the drop in revenue during peak hours. If the profitability of the original plant is significantly compromised, it can jeopardize the entire system.
Batteries with more than three hours of runtime are gaining ground.
The capacity added during this new phase will have different characteristics than the first connected installations. Although two-hour systems can still capture opportunities in the short term, developers are beginning to favor three- and four-hour durations.
The sizing depends on the associated renewable technology, permit conditions, available power consumption, and evacuation limits. In One Hub Energy's analyses, the optimal configuration is typically slightly above three hours.
This evolution is part of a long-term strategy. The sustained increase in solar power generation extends the number of periods with reduced prices and creates the need to shift electricity from midday to peak demand times.
“Arbitrage depends on the volatility of the spot market. In Spain, volatility is guaranteed because there continues to be a high rate of photovoltaic installation,” the specialist explains.
Balance services will provide another source of remuneration, while the future capacity market could offer a more predictable revenue base. Key elements of this mechanism, such as derating factors, the final timetable, and the terms of the tenders, are still to be determined.
Reaching 650 MW this year would mark a change of pace, but it wouldn't necessarily mean a uniform expansion. Large utilities have an advantage in financing assets exposed to variable income, while independent producers and smaller developers will face stricter requirements to secure bank financing for their assets.
Financial institutions still need to accumulate experience, adjust their models, and gain confidence before backing portfolios with high exposure to arbitrage and adjustment services.
The power output registered by Red Eléctrica, the new scheduling units, and the facilities that begin to participate in the system will show whether Spain manages to add the remaining 400 MW before the end of the year.
And, in parallel, as more facilities are added to the operational fleet, it will be very interesting to follow how these facilities operate in different markets, what revenue they manage to capture and how, and what effects they have at the system level.
One Hub Energy expects 2026 to mark the beginning of accelerated storage deployment, but places the real change of scale in 2027, where it will presumably be possible to talk about GW instead of MW installed.