Prices of ready-to-build (RTB) solar PV assets in Spain have dropped 68% over the past two years, while the value of battery projects has surged, according to data by project trading platform nTeaser.

Average prices for solar RTB have dropped from EUR 120,500/MWp in 1Q24 to just EUR 38,000/MWp two years later, according to the data from nTeaser, a digital marketplace for renewable energy and infrastructure deals across Europe.

This sharp decrease follows prolonged spells of low, zero and negative power prices, which have made the asset class unattractive, and unfinanceable, for investors, said Tomas Garcia, head of energy and infrastructure advisory for Iberia at JLL Spain.

Since feed-in tariffs (FIT) were stopped in 2013, power purchase agreements (PPAs) and merchant power sales have been the main sources of revenue for new solar projects in Spain.

But the number of hours when electricity prices fall below zero has been increasing rapidly alongside the growth of Spain’s operational solar fleet, which today stands at around 50 GW, more than a third of the country’s total power generation capacity.

Last year prices turned negative for around 6% of the time in Spain, twice the amount in 2024, according to data from the International Energy Agency.

As a consequence, most banks have pulled back from financing merchant-exposed projects, while even PPA-backed financings are increasingly difficult, Garcia said.

The biggest challenge for securing a PPA involves agreeing a long-term tenor that covers negative and zero prices, he said, adding that Spain is not seeing much of these contracts at the moment.

Solar plant owners can also sell their power on the merchant day ahead and futures markets, while increasingly they have been participating in ancillary services to edge their revenues up by a few euros per MWh, he said.

But unpredictable cash flows means that all of these options are challenging – which has had a knock-on effect on the prices solar developers can command.

Many developers, unable to secure PPAs, have been forced to sell once their projects near RTB status, and this flood of projects on the market is behind the downward pricing pressure, according to nTeaser.

This has created “an oversupply of projects reaching advanced stages simultaneously,” said nTeaser CEO Carmen Izquierdo Serrano, which is forcing investors to be highly selective.

According to nTeaser, only the projects with the most robust financial profiles – the best solar resources and grid access agreements – are surviving this low-price environment, with many others collapsing or being abandoned.

Depending on these factors, RTB prices ranged widely in 1Q26, from around EUR 10,000/MWp to EUR 61,000/MWp, the data shows.

But Serrano said that prices have begun to stabilise, particularly for high quality assets – projects with firm guarantees and clear execution pathways – signalling that the latest repricing cycle is coming to an end.

Infrastructure investors are still hunting for premium solar assets in Spain. JP Morgan Asset Management-backed Sonnedix just last week acquired a 13 MW operational portfolio backed by Spain’s regulated remuneration regime (RECORE), the country’s successor to FIT.

Likewise, on the financing front Bankinter Investment and Plenium Partners raised EUR 530m of debt from CaixaBank and Abanca for a 130 MW portfolio backed by RECORE subsidies in one of the most recent deals.

Supplementing their projects with storage offers a way out for PV developers, making revenues more predictable and projects easier to finance, providing a key differentiator to investors in a competitive market.

“Investors want to understand how projects will perform in a market with structural midday cannibalisation”, nTeaser COO Miguel Galatas Pérez-Juez said. According to nTeaser, hybrid-ready projects, which combine solar and battery energy storage systems (BESS), are increasingly reaching the top end of transaction prices in the RTB market.

Ardian-backed GreenYellow, renewables developer Q Energy and Masdar’s Saeta Yield are among the investors that have targeted hybridised projects since the start of last year, according to Infralogic data.

The buildout of BESS in Spain is expected to improve PV capture prices, Pérez-Juez said, which is helping the technology to retain its value in a fast-changing energy market.

BESS prices surge as revenue clarity increases

RTB prices for Spanish standalone BESS, contrary to PV, are soaring, driven by improving fundamentals for the asset class. Average prices per MW hit EUR 71,500 last quarter compared to EUR 42,000 in 3Q24, the nTeaser data shows.

Higher valuations show how investors’ perception of BESS is rapidly evolving in Spain, driven by improved regulatory certainty and reformed permitting procedures, according to nTeaser.

Last year saw rising investor interest in Spanish BESS, with local developer Solaria Energia and Atlantica Sustainable Infrastructure among the entrants into the market, according to Infralogic data.

Projects currently up for sale are mostly standalone assets, ranging from small distributed units to large-scale clusters in the hundreds of megawatts.

At the top end of the scale are several sales launched earlier this year. Jinko Power in March put up for sale a 486 MW standalone portfolio, while Arena Green Power and Sungrow also launched large portfolio sales.

The government last year held the country’s first auction for batteries, involving the provision of subsidies for 42 standalone projects totalling 720 MW of capacity and 81 hybrid projects totalling 1.4 GW.

And the European Commission last week approved the Spanish government’s inaugural capacity market, a EUR 9bn mechanism in which batteries are anticipated to play a leading role. The capacity market now awaits final government approval before it can be launched.

Currently, BESS revenues are driven by day-ahead and intraday opportunities in arbitrage and participation in several ancillary functions, including aFRR and mFRR.

Contrary to other markets like Germany and Poland, the primary reserve, FCR, to combat grid frequency deviations of up to 30 seconds, is compulsory and not remunerated in Spain.

aFRR – a secondary reserve to stabilise longer grid imbalances of up to 15 minutes – is expected to be very lucrative in the first few years but to be cannibalised quickly once more batteries come online, said JLL Iberia head Garcia.

Further revenues may also come from mFRR, a tertiary reserve for imbalances that last between 15 minutes and two hours.

But with the capacity market, a proposed 15-year capacity payment, batteries will get an all-important additional, predictable and long-term revenue stream.

There are still uncertainties around how batteries will fit into the expected capacity market, Garcia said, including the derating factors they will be assigned.

Capacity market derating factors are assigned to different technologies based on the value they provide during stress events. This is important for batteries, whose absence in the grid last year many observers, including industry body Solar Power Europe, said was a key reason behind Spain’s April 2025 blackout.

This suggests that batteries will be treated favourably, giving further confidence to investors that revenues can be stacked and underwritten with robust financing packages.

According to analyst predictions, the first operational projects in Spain are expected to reap annual revenues in excess of EUR 150,000/MW in the first few years, Garcia said.

All of this points to a rosy outlook for the early movers in Spanish BESS.

The Spanish market is indeed at an early stage, with most projects expecting to hit RTB status this or next year, according to the nTeaser data. But pricing is on a strong upward trajectory, with upper valuations for RTB BESS hitting around EUR 112,000/MW last quarter.

According to nTeaser, batteries with at least a four hour duration continue to command a clear premium, as they can participate in a broader set of revenue streams and have reduced long term revenue volatility.

But as they are also more expensive, investors will need to find the “sweet spot” between additional revenue and increased capex, said JLL’s Garcia.

Projects with a symmetrical grid connection, where the capacity to import and export power is identical, remain one of the most sought-after features by battery investors, according to the nTeaser data.

Yet a significant portion of battery projects under development in Spain do not have such a connection, Garcia said. He said investors favour symmetrical batteries because there are no technical constraints on how to operate the battery, meaning they can optimise revenues.

Regardless, upwards pricing momentum for RTB batteries is expected to continue over the coming quarters, according to nTeaser, as storage is set to become essential infrastructure for the Spanish Power system.