The toll for a good night's sleep

Some mornings an industry agrees with itself too early. On 29 September, at Torre PwC in Madrid, the question of whether battery storage is a good business in Spain was settled in the first conversation of the day. Óscar Barrero, partner in charge of Energy and Utilities at PwC España, launched the RENMAD Talks series, which ATA Insights runs with the firm, without a hint of hedging: "this is the moment, with a capital M". His colleague Fernando Sánchez Vicente, Energy Deals and M&A partner, brought the numbers. His team has advised on five or six sales totalling some 300 MW, with another 750 MW under way, and every one drew "between 12 and 20 serious, solid non-binding offers" from buyers keen to take the projects on. Anyone investing in 2026 or 2027, he added, is looking at a payback (the time it takes to recover the investment) of around four or five years.

Profitable, then. Bankable? That is where the morning really started, and Sánchez Vicente read out the fare himself. With a ten-year tolling agreement, a project can aim for leverage of 50–60%. Fully merchant, selling at market prices, "as things stand, the banks aren't ready to finance it". The rest of the programme was a public negotiation over that gap.

Peak fever

The first warning came from the secondary market. Carmen Izquierdo, chief executive of nTeaser, handles the sale of some 200 portfolios across Europe on her platform, more than 10 GW of them in Spain. She has also analysed around 1,500 offers, from closed deals to binding and non-binding bids and expressions of interest. The most mature standalone projects (batteries without a solar or wind plant next door) command premiums of more than €100,000/MW over the rest. Four things move the price: how soon the project reaches commercial operation; a symmetrical connection, meaning being able to export as much to the grid as the battery draws from it; size, which starts to make sense above roughly 20 MW; and a four-hour duration. She had a message, too, for anyone with projects to sell: "this rise in prices is starting to hit a ceiling". The summer's data already show the curve flattening, as buyers begin to price in narrowing spreads, the gap between the cheap hour when a battery charges and the dear one when it discharges.

Counting the calories

The panel "Margins on a Diet", chaired by Izquierdo herself, put numbers on that squeeze. Spain's project pipeline points to some 14 GW of storage by 2030, and none of the five speakers came close. Melisa Gómez, head of Power Markets at ATA Renewables, reckons on 9 to 9.5 GW; Gerardo Fernández, partner at Baringa, on about 9; Pablo Martínez, head of Iberia at Modo Energy, on about 3 GW standalone and 5 GW hybrid. María Pérez Medel, head of Battery Projects at Naturgy, went no further than five or six, and Luis Palacios, founder and chief executive of Dos Grados, sat closer to her than to the others. "In 2026, investor appetite goes by the name of spread," said Pérez Medel, though she warned that development is very hard and needs financing. Fernández counted the calories: for every gigawatt of batteries beyond those 9, the spread captured in the day-ahead market wears down by €2–3 per MWh.

Martínez, whose clients finance assets on Modo's curves, removed the comfort of forecasts altogether. "When you do a forecasting exercise, it is fundamentally wrong," he said, especially if you mistake the model's curve for reality. Palacios went further: "every project is merchant. Every single one, hedged or not." Martínez put it in trading-desk terms: "if I invest in a battery, I'm going long volatility." To a shareholder, that is an investment thesis. To a bank's risk department, it is a headache with a maturity date.

A tune without the words

The safety net the industry has been waiting for has a name: the capacity market, the first regulated and, in theory, bankable source of income for storage. Barrero supplied the line of the morning: "we know the tune, but we don't know the words." The parameters that set its value are still missing. Nobody yet knows how much firm capacity Red Eléctrica, Spain's system operator, will call for, what peak demand it will assume, the de-rating factors that trim what each megawatt counts for, or how long the contracts will run.

Barrero did the sum out loud. Assume an auction clearing at €30,000–40,000/MW a year, a de-rating of 20–30% and a contract of no great length, and a battery would earn in total "a hundred thousand euros a megawatt, something like that": between 15% and 20% of the investment. "It might improve the leverage a little, but it won't be manna from heaven." Sánchez Vicente added that shareholders leave it out of their base case and treat it as a bonus. Melisa Gómez, looking at neighbouring countries, estimates that capacity payments could supply 20–25% of a battery's revenue: good news for bankability, though not its main pillar.

The ministerial order creating the mechanism, Orden TED/966/2026, was published in the BOE, Spain's official gazette, on 17 September, twelve days before the event. The first auction has yet to be called. Until the words arrive, bankability will have to come from somewhere else.

Peace of mind, tolls apply

That somewhere else filled the day's last big panel, "The Peace-of-Mind Toll", with the people who sign the cheques. María Cuadrado, global head of BESS strategy and development at ContourGlobal, was blunt. Spain already has a deep, liquid market in which batteries earn good returns, "but returns, as we know, don't mean bankability". What it needs are buyers willing to sign structures that turn those returns into something a bank can count on. They are starting to appear: deals that a year ago were seen only in Italy or Britain are now reaching Spain.

Miguel Ángel Amores, head of Renewable Energy at Triodos Bank, translated this into bank-speak. Debt is sized on the debt service coverage ratio (DSCR), which measures a project's cash flow (revenue minus costs) against the principal and interest due each year. For the contracted share of a hybrid PPA (power purchase agreement), Triodos works with ratios of 1.15 or 1.20; for merchant solar, 1.45 or 1.50; for a battery's arbitrage revenue, to be prudent, 1.80 or 1.85, applied to the market advisers' low cases. In plain English, the same battery will carry very different amounts of debt depending on whether it has a contract.

Enter tolling, the toll in the panel's title: the owner hands operation of the battery to a third party in return for a fixed payment over an agreed term. Its more flexible cousin, the floor, guarantees a minimum and shares out whatever comes in above it. Jaime Gorjón, senior director of utility-scale PPAs at EDP, explained how the party offering a floor sets it. If it expects to make 100 over the term, it offers a floor of 40. The real haggling is over the split of the upside: the more the developer gives away, the higher the floor. Amores then set the bank's bar. The floor must be enough on its own to repay the debt at a ratio of 1.0, as though nothing existed above it.

Tenor is the other piece of small print. Contracts are being signed today for seven, ten or twelve years, and Cuadrado reminded the room that a battery lives for twenty or more. Gabriel Deniz, executive director, Sustainability & Low Carbon Advisory, BBVA CIB, made clear that the technology frightens no one. His bank has financed more than 7 GW of batteries in the past 24 months, mostly outside Spain: in the United States, Chile, Italy and Britain. What matters, he insisted, is contracted revenue.

Juan Álvarez, senior solution manager at Envision and the panel's moderator, put it in terms of a mortgage. Asking for a home loan with a payslip behind you is one thing. Walking into the bank and saying "give me a hundred thousand euros, I fancy doing a bit of trading" is quite another. Until the banks catch up, he said, manufacturers are sometimes building the bridge themselves, deferring payment until the financing closes.

Earlier, a panel on grid services, "From Wobble to Poise", moderated by Raúl García of ASEALEN, with Jon Ander López (Jema Energy), Pablo Tena (Rolls-Royce) and Juan Carlos González (ProyectaPV), argued that batteries can offer the grid more services than they are paid for today. Grid forming is one: it holds up voltage and frequency the way a conventional power station would. As for when that money will arrive, González admitted that after so many years it is "almost an act of faith". David Santiago of CATL closed the day by making the case for sodium-ion batteries in large-scale storage.

Price is what you pay

If the contract decides how much debt a battery can carry, the quality of the project decides what it is worth. That was the territory of One Hub Energy, the event's sponsor, which spoke for those who must weigh a battery's risks before committing capital. Eduardo Aguilar, its chief executive, and Juan José Cano, head of Operations, presented a real, anonymised case in which a well-run M&A strategy added close to 32% to the transaction's valuation. They also put a price on waiting: on another project, each month's delay in reaching RTB (ready to build) cost between €3,000 and €4,000 per MW in value. No battery reaches the buyer's table, or the bank's, in better shape than it was prepared.

Hours earlier, on the margins panel, María Pérez Medel had offered the counterweight to all this. She called herself "storage-mad" and admitted that talk of tolling and floors makes her nervous: "don't tie my storage down." Her recipe is a mix: stability at portfolio level, opportunity in market operation. She also had a warning for anyone fixated on financial close: "let's not just think about the pregnancy; the child has to be fed for 18 years, or 38, until it leaves home." Any Spanish parent will recognise the second figure.

What a quiet night costs

If you hold a battery in your portfolio, the question is no longer whether it makes money. It is how much of that return you give up to raise debt, to whom, and for how long. Spain's first non-recourse financing of a standalone battery, the €100m that Grenergy closed in July with Santander and SMBC for its Oviedo project, rested on exactly that: a ten-year tolling agreement. It has every sign of being the first of a series. Deniz said that over the past year, and especially the past six months, more fully formed projects have been knocking on the bank's door. Amores expects banks to grow more flexible with experience, and perhaps even to lengthen tenors.

Whoever can structure that trade-off well (a floor that covers the debt on its own, a contract shorter than the asset's life, the capacity market as a top-up) will be able to borrow more and keep the better side of the swings. Deniz's advice was to talk to the bank before there is a tolling agreement or a PPA at all: "once you start knocking on the door, the ball starts rolling."

Nobody now disputes that batteries make money. What is being haggled over, contract by contract, is the price of sleeping soundly beside one.

Speakers at RENMAD Talks BESS, 29 September 2026, Torre PwC, Madrid, organised by ATA Insights with PwC España: Óscar Barrero and Fernando Sánchez Vicente, PwC España; Carmen Izquierdo, nTeaser; Melisa Gómez, ATA Renewables; Gerardo Fernández, Baringa; Luis Palacios, Dos Grados; Pablo Martínez, Modo Energy; María Pérez Medel, Naturgy; Jon Ander López, Jema Energy; Pablo Tena, Rolls-Royce; Juan Carlos González, ProyectaPV; Raúl García, ASEALEN; Eduardo Aguilar and Juan José Cano, One Hub Energy; Gabriel Deniz, BBVA; María Cuadrado, ContourGlobal; Jaime Gorjón, EDP; Miguel Ángel Amores, Triodos Bank; Juan Álvarez, Envision; David Santiago, CATL. Sponsor: One Hub Energy. The next RENMAD Talks: Autoconsumo Industrial y C&I, 10 November 2026.