Spanish photovoltaics is entering a decisive phase: the challenge is no longer just about building more solar plants, but about preventing existing assets from losing profitability in the face of negative prices, generation restrictions and financial pressure.
This shift in the economic landscape is beginning to stir banks, funds, and investors, who see 2027 as a potential turning point for projects that may need new revenue streams to sustain their debt structures. In this context, co-located batteries are emerging as a technical, financial, and regulatory solution .
“Many photovoltaic plants will have to restructure their debt in 2027. They won’t be able to do so unless they have some additional source of income, which is only possible through some form of added storage,” warned Seamus Brodie, founder and CEO of Lunas Energy, in an interview with Energía Estratégica .
The company seeks to position itself in this new scenario with a specific model: incorporating batteries into existing photovoltaic plants without requiring capital investment from solar owners . Lunas Energy finances, operates, and manages the storage system, while capturing energy that is currently lost or sold at depressed prices.
Along these lines, the company aims to add batteries to 2,000 MW of operational photovoltaic plants in Spain . According to Brodie, Lunas Energy already has agreements for solar assets that would allow the installation of approximately 750 MW of co-located BESS ( Battery Energy Storage Systems), with four-hour batteries capable of achieving around 3,000 MWh of storage per cycle .
The plan targets operational plants and projects under development. The model is more attractive for larger-scale assets, especially those of 10 MW and above, and can improve the bankability of new projects if storage is incorporated before commercial operation.
Brodie argues that Spain offers an additional advantage: adding storage to already permitted plants can be processed as an addendum to the existing permit , which reduces timeframes compared to developing from scratch.
“All we are doing is an addendum to an existing permit, so we don’t have to go through the whole process,” he explained.
The first plants could become operational between the end of 2026 and the beginning of 2027. This timeline coincides with the window in which banks and investors would begin to look more closely at the ability of solar assets to sustain their cash flows.
“Lunas Energy allows PV plants to operate by adding battery storage to their existing plant without requiring any capital investment. We take the power and the negative price that many PV plants have in Spain, use it to charge batteries, and then discharge it at a more convenient time when the grid needs it,” Brodie explained.
“I think the PV plant itself is not a good business model at the moment, but batteries are,” added the founder of Lunas Energy.
Banks on alert and batteries untouched by solar debt
The financial aspect is central. According to Brodie, many owners want to incorporate storage, but they face the existing debt structure of their photovoltaic plants . Adding batteries within the same system can require guarantees, permits, new financing terms, and renegotiations with creditors.
Faced with this bottleneck, Lunas Energy proposes a separate architecture: the battery is structured as an independent company, not tied to the original debt of the solar asset . This would allow them to add a new source of income without completely reopening the plant's financing.
The executive asserts that this formula is already generating interest among financial institutions. Even banks with exposure to solar plants are reportedly seeking alternatives for their clients to incorporate energy storage without straining their existing structures.
The economic incentive is direct: the company estimates that incorporating storage without CAPEX could add between 15% and 20% of additional revenue for a photovoltaic plant , the executive explained.
The capacity market adds a new signal
The discussion comes at a crucial time for Spain. The European Commission has approved Spain's capacity mechanism for €9 billion , with an estimated budget of €900 million annually for ten years, intended to guarantee security of supply and remunerate available capacity in situations of scarcity.
The mechanism will be open to projects located in Spain and includes the participation of generation, storage and demand response , which introduces an additional signal for technologies capable of providing firmness and flexibility to the system.
However, key definitions for investors are still pending. According to Energía Estratégica, the market is targeting 2027 for the first capacity auctions , while the sector awaits information on the contracted volume, firmness criteria, price limits, and the weight of new facilities versus existing assets.
This regulatory context can strengthen the battery business case. But Brodie clarifies that his model doesn't depend exclusively on the capacity market : arbitrage between charging and discharging hours already allows for building a financial thesis.
“We’re loading at one price and unloading at another. Can we afford the CAPEX cost to do that? And yes, we can. Optimization is going to be, in the end, a bonus, and capacity markets and everything else, the balancing and all those things will be a bonus on top of that,” Brodie said.
The challenge for Spanish photovoltaics, then, will not only be to install new megawatts, but to preserve the economic value of solar assets, convert surpluses into income and prepare plants capable of competing in a system where flexibility will have its own price.
In that transition, 2027 appears as a date full of signals: possible debt tensions, first capacity auctions and a race to incorporate batteries.