Curtailment Has Many Names — The Revenue Loss Is the Same

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Europe's growing blind spot

A 2025 report by Beyond Fossil Fuels, in collaboration with E3G, Ember, and IEEFA, found that €7.2 billion in renewable generation was lost across just seven European countries in 2024 due to grid capacity constraints, while 1,700 GW of clean energy projects sit stranded in connection queues, more than three times what is needed to meet the EU's 2030 climate goals.

This is not a technology problem. Wind is blowing, the sun is shining, and projects are fully commissioned. The problem is that grid infrastructure and system flexibility have failed to keep pace with the speed of renewable deployment. The result is a phenomenon that appears under different names across different markets but always means the same thing: clean energy that was produced and never used, and revenue that was earned and never collected.

The IEA's Renewables 2025 report confirms that curtailment levels are rising in a broad range of markets, including Germany, the United Kingdom, Ireland, Brazil, and Chile, as growing shares of variable wind and solar push integration challenges to the forefront. For generators, understanding the mechanics and the terminology of curtailment in each market is no longer optional. It is a core business competency.

The same problem, many names

If you work in renewable generation in Brazil, you know the term curtailment. Speak to a colleague in Chile and they will call it vertimiento. In Spain, the system operator issues restricciones técnicas. In Germany, it is Einspeisemanagement, or simply "EinsMan." In the UK, the term of art is constrained-off.

Same concept, every time: the plant is producing, but the grid operator orders it to stop. The energy never reaches the consumer. The generator's revenue disappears.

United Kingdom — Constrained-off The established technical term used by National Grid ESO. Wind farms in Scotland are routinely constrained off while demand centers in England go unserved, a chronic transmission bottleneck that has persisted for years.

Germany — Einspeisemanagement (EinsMan) An order from grid operators to reduce renewable injection into the network. In 2024, solar curtailment jumped 97% to 1,389 GWh, with Bavaria alone accounting for 986 GWh, or 71% of all PV curtailment in the country. Compensation costs reached €554 million for the year.

Spain — Restricciones técnicas Managed by Red Eléctrica in two phases: pre-dispatch (PDBF) and real-time. Phase I restrictions carry no financial compensation for generators.

France — Écrêtage RTE, the French system operator, uses the term écrêtage de production for generation trimming. In practice, the English term "curtailment" is widely used across European markets by analysts and developers alike.

Greece — Περικοπές A rapidly escalating problem. In March 2025 alone, Greece recorded 200 GWh of curtailed renewable energy, equal to a quarter of the entire 2024 total. The sector is calling for urgent storage deployment and regulatory compensation frameworks.

Brazil — Curtailment / Constrained-off The term is used directly in Portuguese. The ONS classifies curtailment into three types: REL (electrical), CNF (reliability), and ENE (energy surplus). Only REL carries any compensation. In 2025, over 20.6% of all solar and wind generation was curtailed, a loss equivalent to ten months of output from the Belo Monte hydroelectric plant.

Chile — Vertimiento Also referred to as reducción or desacople. In 2024, curtailment reached 5,908 GWh, a 149% increase over 2023. In Q1 2024 alone, nearly one in five MWh of solar and wind output was discarded.

Why this is happening now, everywhere

The underlying explanation is consistent across markets: renewable generation has scaled far faster than the transmission infrastructure and system flexibility mechanisms needed to absorb it. The result is a disturbing paradox, where clean plants are forced offline while the world continues setting emissions records.

The IEA estimates that by 2030, variable renewables will generate nearly 30% of global electricity supply, double today's level. Meeting that target will require a rapid increase in power system flexibility and grid investment across a growing number of countries.

Meanwhile, most European transmission system operators are not yet modeling a 100% renewable system by 2035, and only 13 of the 32 TSOs analyzed by the Beyond Fossil Fuels coalition have specific climate targets incorporated into their infrastructure roadmaps. The gap between the pace of renewable deployment and the pace of grid planning is where curtailment lives.

"What we have is too much generation of the same technology at the same nodes, and since transmission and distribution networks have not been expanded, this generates large amounts of renewable curtailment." Alejandro Diego Rosell, energy consultant, Strategic Energy Europe

Spain: from 0.8% to 11% in twelve months

The trajectory in Spain is among the most dramatic in Europe. Data from Red Eléctrica confirm that between July 2024 and April 2025, the share of renewable energy not integrated due to technical restrictions remained stable at around 1–3%. From May 2025, there was a sharp escalation: in July, curtailment peaked at almost 11%, before falling slightly to 7% in August.

More than 1,100 GWh could not be integrated into the system in July 2025 alone, compared to just 0.8% curtailed in July 2024. The provinces most affected were Toledo, Ciudad Real, and Granada, where more than 30% of local renewable production was cut.

Two overlapping factors drove the spike: a natural seasonal surge in solar generation combined with a structural change in how Red Eléctrica operates following the historic blackout of April 2025. According to Kiko Maza of WeMake Consultor, "restrictions are now stricter, so we can deduce that Red Eléctrica has changed its criteria for integrating renewables." System security costs surged as a result, with Red Eléctrica's reinforced operating plan pushing total restriction costs to €3.77 billion in 2025, up 49% from €2.52 billion in 2024.

Germany: a 97% surge in solar curtailment

Germany nearly doubled the volume of curtailed solar PV electricity in 2024. According to the Bundesnetzagentur, 1,389 GWh of solar generation was curtailed, a 97% increase compared to 2023. Bavaria bore the brunt, with 986 GWh of solar generation cut from the system, reflecting the state's dominant share of distributed PV and the limits of current grid flexibility in absorbing midday peaks. Renewable re-dispatch averaged €200/MWh in 2024, with total compensation costs for curtailed renewables reaching €554 million for the year.

Greece: a quarter of a year's curtailment in a single month

In March 2025, Greece recorded 200 GWh of renewable energy curtailment, a figure representing one-fourth of the total curtailment accumulated during all of 2024. The data, presented by the Vice President of Greece's Independent Power Transmission Operator (IPTO), set off alarms across a sector that sees the viability of new clean capacity at risk unless current grid bottlenecks are resolved. Studies conducted in Greece show that for every 1 GW of standalone battery energy storage deployed, curtailment can be reduced by between 0.62 and 1.18 TWh. The Greek government's regulatory framework for new storage has set a ceiling of 4,700 MW, but experts warn this may not be sufficient to absorb all excess renewable generation.

Latin America: the same structural crisis at a different scale

The European curtailment crisis has a mirror in Latin America, and the numbers are starker. In Chile, the ACERA executive director summarized 2024 with a striking observation: the amount of energy curtailed that year was greater than all the new solar energy injected into the system combined.

In Brazil, the escalation from 0.5% curtailment in 2022 to 20.6% in 2025, with R$ 6.5 billion in estimated losses, represents one of the fastest deteriorations in grid integration performance of any major renewable market globally.

What is at stake for generators

Curtailment is not merely a technical loss. It directly erodes project cash flows, complicates PPA delivery obligations, undermines debt service coverage ratios, and threatens the bankability of future projects.

Europe's H1 2025 curtailment losses equated to £152 million in forgone revenues, inflating PPAs by 5–10% in Spain and deterring an estimated €20 billion in new investment. Globally, the revenue lost from curtailed energy in 2024 alone exceeded $20 billion, with IRENA estimating cumulative foregone benefits at $100 billion by 2030 if left unaddressed.

For lenders and equity investors, curtailment risk has become an explicit line item in financial modeling. As Kiko Maza of WeMake Consultor warns: "it forces more energy to be curtailed in business cases, which makes it harder to make the numbers work and for the project to secure financing." The greater the uncertainty around generation being utilized, the higher the perceived risk for banks and investors.

The solutions the market is pursuing

There is no single answer. Reducing curtailment requires a combination of infrastructure investment, regulatory reform, and smarter operational management.

Grid expansion and modernization remains the most impactful long-term lever. The Beyond Fossil Fuels report recommends that European governments prioritize connecting renewable projects already in operation, increase storage capacity, and implement demand-side flexibility at scale. But new transmission lines take years to permit and build and face growing social and environmental resistance in many markets.

Battery energy storage (BESS) is the most rapidly deployable tool for shifting generation away from peak surplus hours. Globally, battery storage deployments increased 53% in 2024, with 205 GWh installed and costs falling 40% to $165/kWh, making storage-paired projects increasingly viable as a curtailment mitigation strategy.

Grid Enhancing Technologies (GET), including dynamic line rating, power flow controllers, and topology optimization, can increase the capacity of existing lines without new construction, at a fraction of the timeline and cost.

Intelligent forecasting and operational management allows generators to anticipate curtailment windows hours or days in advance, adjust dispatch strategies, optimize market participation, and protect revenue before losses materialize. This is where technology delivers the fastest return in the current environment.

"It is not enough to look at system averages. You need node-by-node analysis to understand the real implications for each project." Chema Zabala, Managing Director at Alantra Energía, Strategic Energy Europe

Monitoring as competitive advantage

In a market defined by structural and growing curtailment, generators who rely solely on historical data from Red Eléctrica, Bundesnetzagentur, or IPTO to understand their exposure are always reacting and never anticipating. The difference between absorbing curtailment passively and actively mitigating it comes down to the quality and speed of the information available.

Delfos Energy was built for exactly this gap. Our platform integrates real-time operational data, dispatch modeling, and constraint analysis by subsystem, giving generators visibility into curtailment risk before it materializes, not after.

Stop finding out about curtailment after it happens

Learn how Delfos Energy helps solar and wind generators monitor, anticipate, and mitigate revenue losses from operational restrictions in real time.

Information compiled from public data published by Red Eléctrica de España, Bundesnetzagentur, IPTO, IEA, ONS, CEN, and specialist publications including Strategic Energy Europe, pv-magazine, Ember, Beyond Fossil Fuels, and the Energy Central.

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