Energy storage is accelerating in Spain. With nearly 290 MW of installed battery capacity , the country could more than double its total capacity and reach around 650 MW by 2026, provided that the projects currently under construction become operational before December. This momentum is also reflected in the permitting process: in August alone , 327.6 MW of battery storage and energy efficiency systems (BESS) advanced, primarily through hybridization with existing photovoltaic plants.
However, pipeline growth doesn't automatically translate into completed projects. Administrative delays, revenue uncertainty, and limited operational experience maintain a gap between announcements and final investment decisions.
For Iosu González Albín , head of Photovoltaic Engineering and BESS at Kalin Electricity Solution , the first difficulties appear before the start of construction.
“The lack of regional homogeneity is a major bottleneck; each autonomous community applies different criteria and requires new environmental procedures,” he explains.
This dispersion is compounded by the lack of clear criteria on fire protection, an indefiniteness that delays licenses and grants an increasing role to insurers in the technical evaluation.
“These entities are currently being extremely demanding. They audit and oversee technical reports and impose requirements that, in some cases, are not even required by the regulations themselves,” says González Albín.
The new conditions could increase insurance costs, require engineering modifications, and compromise bankability. Obtaining permits and selecting equipment is no longer enough: projects must demonstrate that their technical, operational, and safety risks are under control.
Having passed the insurance filter, the financial filter comes into play. The small installed base in Spain still provides little real data on degradation, availability, costs, incidents, and revenue—essential variables for projecting a battery's performance throughout its lifespan.
In this context, Álvaro Simón , founder of ASB Renewables Consulting , identifies a mismatch between the expectations of buyers and investors and the actual development timelines. Having access, initiating the permitting process, or reaching " ready to build" status no longer guarantees an asset's attractiveness.
“The first thing is certainty. Certainty, first, in development,” Simón summarizes.
Funders need to know when each project will begin operations and what revenue it can sustain. According to the consultant, traditional banks still avoid structures with market exposure they cannot confidently model.
Each new installation will provide benchmarks for evaluating subsequent projects and reducing that perception of risk. Until then, the market will move at two speeds: a rapidly growing pipeline and investment decisions that require much more than just permits.
Hybridization takes advantage
While these unknowns are being resolved, batteries associated with renewable energy plants are progressing more easily than independent projects.
The applications approved during August show a defined pattern: systems connected to existing photovoltaic installations, replicable designs, and shared evacuation infrastructures.
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In Altarejos, Cuenca, four virtually identical modules added 86.76 MW of storage capacity. In Seville, four other projects concentrated 147.17 MW around solar plants located between Los Molares, Alcalá de Guadaíra, and Utrera.
This model allows for the reuse of some infrastructure and reduces development time and risks. Independent projects, on the other hand, may encounter additional barriers.
The BESS Solórzano project, with a capacity of 49.74 MW and 199.52 MWh, obtained the energy authorizations but not the requested declaration of public utility. The developer will have to secure land ownership and the necessary easements through private agreements.
Hybridization doesn't solve all the problems either. When a battery lacks sufficient demand capacity to charge from the grid, its operation is limited to the energy produced by the associated power plant. This reduces its flexibility and the alternatives for generating revenue.
González Albín identifies a more immediate opportunity in existing industrial photovoltaic installations. These are assets whose production is already known and which, in some cases, have already been amortized.
Adding storage allows you to take advantage of surpluses, reduce consumption peaks, and shift demand towards more convenient tariff periods.
This shift is also transforming the design of solar power plants. Low prices during peak hours reduce the incentive to maximize generation at midday. Engineering must be more precisely tailored to the customer's consumption pattern.
“We no longer always seek maximum peak production with a south-facing orientation, but rather adapt the design to actual consumption or incorporate storage,” he points out.
Developers are also beginning to evaluate longer-lasting systems. While two-hour batteries can still capture short-term opportunities, three- and four-hour configurations are gaining traction for shifting larger volumes of solar energy to periods of peak demand.
Quality also enters into the equation
The new phase demands greater attention to equipment quality and asset durability . During inspections of existing facilities, the Kalin team finds workmanship defects and components chosen without sufficiently assessing their long-term performance.
González Albín warns against the “use of increasingly larger modules with thin glass and structures that may prove insufficient to support their dimensions and mechanical loads.” He also questions the “installation of bifacial panels on roofs where their additional contribution may be limited.”
Engineering must ensure that reducing initial costs does not compromise safety, performance, or lifespan. This review will become increasingly important as insurers, banks, and investors raise their standards.
Kalin Electricity Solution designs, supplies, installs, and commissions photovoltaic and energy storage systems for businesses. Their approach begins with analyzing load curves, peak consumption, and seasonal demand variations to determine the optimal size for each solution.
The next step will be to integrate these assets through intelligent energy management systems. González Albín sees potential in artificial intelligence applied to EMS, capable of anticipating renewable production, consumption, and prices to optimize battery charging and discharging.