According to a preprint posted for discussion in the journal Wind Energy Science, an offshore wind farm that switches its turbines off whenever the projected farm revenue drops below a threshold can, under the right conditions, spare its machines so much structural stress that they could keep running for roughly a decade longer than they otherwise would. But the size of that prize depends on something the wind farm itself cannot control: whether the surplus power that drives prices negative comes from wind or from solar.
The study, led by Moritz Gräfe of DTU Wind and Energy Systems at the Technical University of Denmark, with co-authors from the Technical University of Munich, the National Renewable Energy Centre in Spain and DTU, is currently under review for Wind Energy Science. Rather than treating curtailment, structural fatigue, revenue and carbon accounting as separate problems, the authors built a single model that combines control, fatigue loads, contract settlement, financing and carbon accounting, and used it to simulate the Lillgrund offshore wind farm hour by hour. The preprint is a discussion-stage contribution, so its numbers have not yet been through peer review.
A central question the authors set out to answer is what happens when the hours in which a wind farm would be paid to stop are hours in which the wind is blowing hard. Negative prices arise when the supply of electricity exceeds demand, and whether they fall in windy hours depends on whether wind or solar feed-in causes the surplus. That distinction turns out to be decisive, because the hours a farm skips to avoid negative prices are not interchangeable: some carry heavy mechanical loads, others do not.
To isolate this effect, the team constructed three price futures with the same share of negative-price hours, driven respectively by wind, by a mix of wind and solar, and by solar. Holding the frequency of negative prices constant across the scenarios means the differences the model produces can be attributed to what those hours contain, not to how often they occur. In each scenario, the farm followed one simple farm-wide rule: stop all turbines in hours in which the projected farm revenue falls below a threshold, which the researchers varied from zero to low positive values.
The controlled shutdown removes the hours of lowest revenue, and the authors write that the driver of the negative prices decides what else those hours carry. Under wind-driven prices, the hours that get cut are windy hours with high fatigue loads, so the turbines avoid the most damaging operating conditions. The fatigue budget left unused by this avoidance permits a lifetime extension of about ten years. Under solar-driven prices, by contrast, the hours that get cut are hours of average wind, and the extension is only about one year.
The financial consequences of that difference are striking. The years of extra operation gained through load-reducing curtailment are worth a few million euros in every price future the team examined, even though the size of the gain varies enormously between the wind-driven and solar-driven cases. In other words, the same curtailment rule applied to the same farm, facing the same number of negative-price hours, can deliver either a substantial structural dividend or almost none, depending solely on the technology mix that pushes prices below zero.
The carbon accounting tells a similar story. The net displacement of emissions rises by about 17 percent under wind-driven prices, according to the preprint, and falls slightly under solar-driven prices. This follows directly from the load structure of the curtailed hours: when the skipped hours are windy, the farm forgoes generation in exactly the periods when it would otherwise have been producing at high output, and the model tracks how that trade-off plays out for the climate value of the electricity the farm delivers over its extended life.
The study also reaches into the design of support schemes, where the picture becomes more complicated. The authors compared three contracts for difference that require the same support in present value. Under a production-based contract, which pays nothing on energy delivered at negative prices, the strike price rises by about 40 percent under wind-driven prices. Two capability-based contracts, which instead pay on the energy the farm could have delivered, keep their strikes near their historical level. The distinction matters because the two contract families reward fundamentally different behaviour: one pays only for electricity actually delivered, the other pays for availability regardless of whether the farm chooses to run.
That difference in contract design turns out to gate the entire curtailment opportunity. The authors report that raising the revenue threshold above zero adds little value in their scenarios, and that a contract settled on delivered energy blocks any load-reducing control whose fatigue value lies below the difference payment. In practical terms, a farm paid strictly on delivered energy has no room to switch off for structural reasons, because the revenue it would sacrifice in negative-price hours outweighs the mechanical benefit of running less. Only a contract that pays on available energy at every price leaves the decision to the operator, allowing the farm to weigh revenue against fatigue without being penalised for doing so.
The findings arrive at a moment when negative prices are becoming an increasingly routine feature of European electricity markets, driven by the growing share of wind and solar generation on the grid. The preprint’s contribution is to show that the response to those hours should not be designed in isolation from turbine structural life, contract design or emissions accounting, because the same hour of negative price can carry very different consequences for each. The authors’ own short summary puts it plainly: stopping in windy hours spares the turbines so much load that they can run years longer, while stopping in sunny hours gains far less, and the farm’s support contract decides whether it can use this gain.
As with any simulation study, the results carry limits that the authors themselves frame through their method. The analysis covers a single offshore wind farm, Lillgrund, simulated hour by hour under constructed price futures rather than observed market outcomes, and the preprint is at the discussion stage of peer review. The headline numbers, a decade of extra life under wind-driven prices, a single year under solar-driven prices, a 17 percent rise or a slight fall in net emissions displacement, and a 40 percent strike increase for one contract type, are therefore model estimates for this farm and these scenarios rather than measurements from operating plants. Even so, the direction of the result is clear within the study’s scope: the value of switching turbines off in negative-price hours depends on what those hours contain, and the contract a farm signs determines whether it can act on that knowledge at all.
Subject of Research: How revenue-triggered curtailment of an offshore wind farm affects turbine lifetime, economics and emissions under wind- and solar-driven negative electricity prices, and how support-scheme design shapes the outcome.
Article Title: Wind farm value, revenue-triggered curtailment and support-scheme design under wind- and solar-driven negative prices
Article References: Gräfe, M., Kainz, S., Pettas, V., Ioannou, A., Kolios, A., Göçmen, T., Sandua-Fernández, I., Eguinoa, I., & Dimitrov, N. (2026). Wind farm value, revenue-triggered curtailment and support-scheme design under wind- and solar-driven negative prices. https://doi.org/10.5194/wes-2026-188
Image Credits: AI Generated
DOI: 10.5194/wes-2026-188
Keywords: offshore wind, negative electricity prices, curtailment, fatigue loads, lifetime extension, contracts for difference, support schemes, solar power, wind energy, emissions displacement, simulation study, energy economics
News Source: Faith Mcneil. (October 28, 2026). Switching turbines off in windy hours could add a decade of life. Scienmag.
