Spain
A shared Iberian day-ahead auction with Portugal, one of Europe's highest renewable shares, and the continent's largest cluster of LNG import terminals. Weakly wired to France, and consequently a market that must absorb its own surpluses by price.
Overview
Spain runs one of Europe's largest and most renewable-heavy power systems, clearing on a shared Iberian day-ahead auction with Portugal. It also holds the continent's biggest fleet of LNG import terminals. A renewables market and a gas market at the same time.
Wholesale electricity trades on OMIE, the nominated electricity market operator for the Iberian Electricity Market (MIBEL) — a single day-ahead auction covering Spain and Portugal, coupled into the wider European market since 2014 (OMIE). Red Eléctrica operates and plans the Spanish transmission system. Gas moves through Enagás's network and prices at the MIBGAS hub.
Three things make Spain unusual. The renewable share is very high — 55.5% of 2025 generation came from renewables, with wind at 21.6% and solar PV at 18.4% (Red Eléctrica). The peninsula is barely joined to the rest of Europe: 2,800 MW of interconnection with France, saturated 76% of hours over the past three years (INELFE). And Spain is a major LNG entry point for Europe, with six active receiving terminals (IEA).
Two events define the recent record. The Iberian exception of 2022–24 capped the gas price generators could put into their offers, a direct intervention in marginal pricing that the rest of Europe watched closely. Then on 28 April 2025 the peninsula went dark. The first cascading generation-disconnection blackout in continental Europe (ENTSO-E).
Spain is the live experiment in what a very high renewable share does to a weakly interconnected system: midday prices, system stability, the value of firm capacity. Whatever gets concluded here is being applied to markets that will look like Spain in five years.
Market structure
A single Iberian auction, a single transmission operator, and a regulator that sits underneath European market rules rather than above them.
Who does what
| Function | Body | Role |
|---|---|---|
| Power exchange | OMIE | Sole NEMO for Spain and Portugal; day-ahead and intraday auctions |
| Transmission and system operation | Red Eléctrica | Sole TSO; grid planning, balancing and restoration |
| Gas transmission | Enagás | Technical system manager for gas; owns the trunk network and most terminals |
| Gas trading hub | MIBGAS | Spot and derivative trading at the Virtual Balancing Point |
| Regulator | CNMC | Network tariffs, market surveillance, access rules |
| Policy | MITECO | Energy and climate policy, auctions, capacity mechanisms |
MIBEL: one market, two countries
Spain and Portugal clear as a single price zone whenever the interconnection between them is uncongested, which is most of the time. When it binds, MIBEL splits and the two countries price separately. Check that first. An Iberian price is usually one number and occasionally two, and the split turns up in exactly the windy, sunny hours when the position matters most.
Coupled to Europe, but through a bottleneck
The MIBEL day-ahead auction runs at 12:00 CET and is coupled with the rest of Europe through SDAC, with price limits of +4,000 to −600 EUR/MWh. Intraday runs as three auction sessions plus the continuous cross-border market, tradable up to an hour before delivery (OMIE).
Coupling only equalises prices to the extent that wires exist. Set 2,800 MW of France–Spain capacity against a system with well over 40 GW of peak demand and Iberia is coupled on paper, semi-islanded in practice. Iberian surpluses cannot be exported away. They get absorbed at home, by price.
An oversupplied German hour exports into a continent. An oversupplied Spanish hour has almost nowhere to go. That single fact explains most of what follows about negative prices, curtailment and capture rates.
Infrastructure — power and gas
A single national transmission system with a thin border to France, and a gas network built around the largest set of LNG receiving terminals in the European Union.
Power
One TSO
Red Eléctrica owns and operates the transmission grid and performs system operation, planning and restoration — no regional split, no separate ISO.
142.5 GW installed
Total generating fleet at end-2025, of which solar PV is the largest single technology at 33.1% of installed capacity, with 3,427 MW of storage.
2,800 MW to France
The only meaningful link to the rest of the synchronous European system, saturated in 76% of hours over the last three years.
Capacity figures are from Red Eléctrica; interconnection figures from INELFE.
The interconnection build-out
One project changes that. The Bay of Biscay submarine HVDC link is two 1,000 MW links across roughly 400 km of cable, around 300 km of it undersea, lifting France–Spain exchange capacity from 2,800 MW to 5,000 MW. Budget €3.1bn, with €578m of Connecting Europe Facility support. Testing begins mid-2027, definitive commissioning in 2028 (INELFE). Until it energises, Iberian price formation stays largely a domestic affair.
Gas and LNG
Spain has six active LNG terminals, 25 storage tanks and eight berths that take vessels of up to 270,000 m³. Barcelona alone can regasify 48.1 mcm/day. Four underground storage sites at Gaviota, Serrablo, Yela and Marismas hold roughly 3 bcm, and Spain's N-1 infrastructure resilience metric stands at 123% (IEA). Enagás owns Barcelona, Cartagena and Huelva outright and holds majority or half stakes in Musel, Bilbao and Sagunto (Enagás).
Schematic — system topology, not a geographic map. Iberian gas and power flows converge on a single day-ahead auction, with a narrow 2,800 MW window to France.
Demand and supply
Demand is growing again. Wind, nuclear and solar dominate the mix, and gas has been pushed out to the margin, where, awkwardly for gas-fired economics, it still sets the price.
Demand
Spanish electricity demand reached 256,086 GWh in 2025, up 2.8% on 2024; including self-consumption the figure is 269,753 GWh, up 3.7% (Red Eléctrica). After a decade of stagnation, electrification, data centres and industrial reshoring have restarted growth. Set it against the pace of renewable additions and it is small.
Supply
75.5% of 2025 generation was free of CO₂-equivalent emissions, and Ember puts Spain's low-carbon share at 75% against an EU average of 71% (Ember). Combined cycle gas plant supplied 16.8%, a residual role concentrated in evening and low-wind hours.
Shares for 2025, excluding self-consumption. Source: Red Eléctrica, corroborated by Ember.
| Indicator | Direction | Comment |
|---|---|---|
| Electricity demand | Rising | Up 2.8% in 2025; electrification and data centres |
| Solar PV | Rising fast | 33.1% of installed capacity at end-2025 |
| Nuclear | Stable, then declining | 19% of 2025 generation; a phase-out schedule sits over the fleet |
| Gas-fired generation | Squeezed | Fewer running hours, but still frequently marginal |
| Storage | Rising from a low base | 3,427 MW installed at end-2025 |
The capture-rate problem
Spanish renewable volume risk is shape risk wearing another name. The megawatt-hours arrive; they arrive in the hours when everyone else's do too. Value has migrated to whatever shifts energy in time: batteries, pumped hydro, flexible demand.
Price setting mechanism
A marginal-cost auction like any other European market, with one difference. Spain has already run the experiment of interfering with the marginal price, and published the results.
How the auction clears
Generators submit offers to OMIE for each hour of the following day. Offers stack cheapest first, and the last unit required to meet demand sets one clearing price paid to everyone who cleared. Wind, solar, nuclear and run-of-river all offer at or near zero. So the marginal unit in Spain is usually a CCGT in the evening peak and, more and more often, nothing at all at midday.
The midday collapse
With solar at 33.1% of installed capacity, the middle of the day now clears at zero or below as a matter of routine. Spain recorded 247 negative-price hours and roughly 470 zero-price hours in 2024, over 8% of all traded hours. The negative count roughly doubled in 2025, and average negative prices deepened from about −€1.5/MWh to around −€6/MWh (Storpeak). The MIBEL floor is −600 EUR/MWh (OMIE), so there is a long way further down before the mechanism runs out of range.
The Iberian exception, 2022–24
In June 2022 Spain and Portugal were allowed to cap the gas price generators could pass into their offers, with the difference recovered through a levy on the consumers benefiting from the lower clearing price (IEA). A direct intervention in marginal pricing, and a public demonstration of the arithmetic: lower the marginal offer and the whole curve moves, inframarginal rent on plant that burns no gas included. It demonstrated the cost as well. The subsidy leaked across the border through exports to France, and somebody still had to pay the compensation.
The retail linkage
Spain's regulated retail tariff passes the OMIE hourly price straight through to households. Since January 2024 it has been progressively blended with forward-market references: 25% forward in 2024, 40% in 2025, and 55% from 2026 as the permanent setting (RD 446/2023). The intent was to damp volatility. The market effect is that a growing share of Spanish household demand now sits hedged into the forward curve instead of exposed to spot.
Regulatory regime
A European market design implemented nationally: CNMC regulates, MITECO sets policy, and the binding constraints increasingly come from Brussels and from the lessons of one afternoon in April 2025.
| Body | Remit |
|---|---|
| CNMC | Energy regulator: network tariffs, access, market surveillance and competition |
| MITECO | Energy and climate policy, renewable auctions, the national energy and climate plan |
| Red Eléctrica | System operation, grid planning and restoration under regulated remuneration |
| Enagás | Technical manager of the gas system; third-party access to network and terminals |
| ACER / ENTSO-E | European coordination of market rules, coupling and system-operation standards |
28 April 2025 and what changed
At 12:33 CEST on 28 April 2025, continental Spain and Portugal lost supply entirely. The most severe European incident in more than twenty years, and the first cascading generation-disconnection blackout in continental Europe. ENTSO-E's expert panel reported in full on 20 March 2026 and identified gaps in voltage and reactive-power control, differing voltage regulation practices, uncontrolled oscillations, and rapid output reductions and generator disconnections in Spain (ENTSO-E).
The regulatory consequences run one way. Services previously assumed rather than procured are becoming products. Voltage and reactive-power control, synthetic and synchronous inertia, grid-forming inverter capability and stricter ride-through obligations for renewable plant are all moving out of technical annexes and into commercial terms. Hold Spanish assets and that is a change in the revenue stack: new ancillary income for equipment that can provide these services, new compliance cost for equipment that cannot.
Where the regime is heading
Three threads to watch. Grid investment: reinforcing the network and accelerating the Bay of Biscay link is now a security argument as much as an economic one. Nuclear: the scheduled phase-out of a fleet supplying 19% of generation sits awkwardly beside a system that has just found out how much it values synchronous machines. Storage remuneration: 3,427 MW installed against a 33.1% solar capacity share, and the gap between what the system needs to shift energy in time and what it currently has is the clearest regulatory opening in the market (Red Eléctrica).
Key links
Primary sources for this market. Figures on this page are drawn from these and from published market data.