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Glossary · Energy industry & energy transition

Capture Rate

Capture rate Capture price market value market value factor wind energy photovoltaics electricity market Cannibalization effect

The capture rate indicates what share of the average market price a power generator earns with its actual feed-in profile. This can be a single plant, a portfolio or an entire technology. A specific period is always considered. At 100 percent, the average price achieved equals the market average exactly. If the value is lower, more electricity was fed in at times of below-average prices. If it is higher, generation tended to fall at times of high prices. The indicator therefore depends on when electricity is fed in, not on how much.

Definition and calculation

The so-called capture price is divided by the simple average market price in the same period. The capture price is the generation-weighted average price. To obtain it, each megawatt hour generated is valued at the price of the trading period in which it was fed in. The sum of these revenues is then divided by the total quantity generated. The capture price has a monetary unit, such as euros per megawatt hour or cents per kilowatt hour. The capture rate, by contrast, is a dimensionless ratio and is usually stated as a percentage.

A simple example: a photovoltaic plant earns an average of 50 euros per megawatt hour in a month. The average exchange price in the same month is 70 euros per megawatt hour. The capture rate is then 50 divided by 70, or around 71 percent. A real example from Germany: for 2025, the transmission system operators published an annual average spot market price of 8.932 cents per kilowatt hour. The annual market value for solar was 4.508 cents, for onshore wind 7.441 cents and for offshore wind 8.059 cents. This results in capture rates of around 50 percent for solar, 83 percent for onshore wind and 90 percent for offshore wind.

The day-ahead price of the relevant bidding zone is often used as the reference price. It is widely used, but it is not the only possible reference. In Germany, the power exchanges now determine the spot market price of the day-ahead auction in quarter-hours. The statutory market value calculation also works in quarter-hours. An analysis should therefore always state which period, which market and which time resolution are used. In addition, a capture price based on day-ahead prices is not the same as an operator's actual revenues. These may come from direct marketing, balancing energy, long-term supply contracts or support mechanisms. The capture rate initially describes only a price relation on the electricity market, not the full economic return of a plant.

Distinction from capture price, market value and market value factor

The capture price is an absolute value. The capture rate puts it in relation to the market average. It thus shows whether a feed-in profile was favourable or unfavourable in terms of price. In the German support system, the term market value exists for this. Under Annex 1 to the EEG (German Renewable Energy Sources Act), the energy-source-specific market value of wind and solar power is calculated as follows: the spot market price of each quarter-hour is multiplied by the extrapolated generation of the technology. The products are added up and divided by the total quantity generated. Methodologically, this corresponds to a technology-wide capture price. The market value factor puts this market value in relation to the average price and thus corresponds in essence to the capture rate. In international analyses, the term capture rate is mostly used.

A particular feature of the EEG calculation method: it is based on an online extrapolation of generation derived from measured reference plants. Curtailments by the grid operator or within direct marketing are expressly not taken into account. The official market value is therefore a reference value for the entire technology. It is not the capture price of a specific plant, whose location, orientation and curtailment may deviate from the average.

The capture rate is not the same as annual yield. Yield is a quantity of energy in kilowatt hours or megawatt hours. The capture rate, by contrast, values the point in time at which this energy is generated. A technically highly productive plant can have a low capture rate if it feeds in mainly at low-price times. Conversely, a high capture rate says nothing about whether a plant is economically viable despite high investment, grid connection or operating costs. The indicator must also not be confused with levelised cost of electricity. These describe the average generation costs over the lifetime. For a statement on economic viability, revenues, costs, support rules, financing and risks must be considered together.

Why the feed-in profile shapes the market value

The capture rate is particularly important for weather-dependent generation from photovoltaics and wind energy. These plants do not produce when the price is high, but when sun or wind is available. With only a few plants, this has hardly any influence on price formation. With a high share of similar plants, however, prices shift.

Photovoltaic plants largely feed in at the same time around midday. If demand does not rise enough in these hours, storage units do not charge sufficiently, flexible consumers hardly react or export options are limited, the exchange price falls. It can then even slip into the range of negative electricity prices. Solar power is therefore sold precisely when additional solar supply pushes down the price. This is clearly visible in Germany: in 2025, the capture rate of solar power was only around half of the average spot price. In May and June 2025, the monthly market values for solar were even below two cents per kilowatt hour.

For wind energy, a similar effect arises in windy weather conditions, when many wind farms generate large amounts of electricity at the same time. It is usually weaker than for photovoltaics, however. Wind is spread more widely across times of day and seasons, and weather patterns affect different regions differently. This is also shown by the significantly higher capture rates of onshore and offshore wind in 2025. The basic question remains the same: how strongly does the generation of a technology coincide with low or high market prices?

This relationship is often referred to as the cannibalisation effect. Additional plants with a similar generation profile can reduce the market value of existing plants of the same technology. The capture rate makes this effect measurable. However, it does not by itself show how strongly a project is affected economically. Revenues also depend on support mechanisms, hedging transactions, self-consumption, site quality and marketing strategy.

Significance in the German support system

In Germany, the technology-specific market value directly determines the amount of the market premium under the EEG. The market premium is the difference between the applicable value (anzulegender Wert) and the market value. If it is negative in the calculation, it is set to zero. Which market value applies depends on the plant's vintage. For plants that were commissioned before 1 January 2023 or received an award before then, the monthly market value generally applies. For other plants, the annual market value applies. Older plants that use the delimitation or flat-rate option under § 19 paragraph 3b or 3c are also settled on the basis of the annual market value. The transmission system operators publish the monthly values by the tenth working day of the following month and the annual values by the tenth working day of the following year.

The switch to the annual market value has consequences for risk. With monthly settlement, the sliding market premium compensates for low summer values within the same month. With annual settlement, this is not the case: a plant that feeds in better than the technology average at high-price times can benefit. A plant with a less favourable profile, by contrast, bears more revenue risk. In addition, under the rules of the so-called Solarspitzengesetz (Solar Peak Act) introduced at the beginning of 2025, newer EEG plants receive no support at times of negative prices. This strengthens the incentive for these plants to avoid or shift generation at low-price times.

Relevance for investment, flexibility and market design

For investors, the capture rate shows whether future revenues may be estimated using the average exchange price. Even for dispatchable power plants, this is only an approximation. For weather-dependent plants, however, it can distort particularly strongly. Anyone who values solar or wind projects only with average annual prices may overestimate revenues if the feed-in profile systematically falls at low-price times.

For the power system, the indicator shows how valuable flexibility is. Battery storage can absorb electricity at times of low prices and release it again at higher prices. Flexible demand can also make better use of low-price generation hours, for example through electrolysers, heat pumps with buffer storage, industrial load shifting or smart charging of electric vehicles. Grid expansion and a geographically broader distribution of plants can reduce simultaneous surpluses or distribute them better.

The capture rate thus also concerns the question of how an electricity market with high shares of renewable energy sets investment signals. If very many plants produce in the same hours, their market value falls. Without additional revenue sources, support instruments or sufficiently flexible demand, this can slow down expansion. At the same time, the price decline is a meaningful signal: electricity is abundant in these hours and should be used, stored or transported to other regions.

How important the capture rate is for a project depends on who bears which risks. Under the sliding market premium, the support mechanism takes over part of the market value risk. For unsubsidised projects or long-term electricity supply contracts, a power purchase agreement, the profile risk is shared between plant operator, offtaker and marketer. For contracts for difference, capacity mechanisms or technology-specific tenders, the situation is different because revenues do not come solely from the short-term exchange price. The indicator remains important, but must be placed within the respective market and support framework.

Typical misinterpretations

A low capture rate does not mean that a technology is technically poor or useless from a macroeconomic perspective. It initially shows only that the electricity is generated at times of low prices. Solar power can nevertheless be valuable if it displaces fossil generation, reduces import needs or covers load during the day. The falling market value does show, however, that additional plants with the same profile earn less revenue per kilowatt hour without accompanying flexibility.

Conversely, a high capture rate is not complete proof of quality. A plant can have a high capture rate because it generates rarely, but at high-price times. If the total quantity is small or the costs are high, economic viability does not follow. Over short periods or with few data points, the indicator can fluctuate strongly. Individual high-price phases, a Dunkelflaute (prolonged period of low wind and sun) or hours with negative prices can distort monthly values considerably.

The type of averaging also changes the result. Anyone who takes the average of twelve monthly capture rates obtains a different value than with a volume-weighted annual calculation. In the annual calculation, the high-generation summer months with low prices count for more. For solar power in Germany in 2025, the simple average of the monthly ratios was around 65 percent. The ratio of the official annual values, by contrast, was around 50 percent. Both values are calculated correctly, but answer different questions.

Particular caution is needed when the average market price is very low, zero or negative. Because the capture rate is a ratio, small changes in the denominator can then produce large swings. With an average price close to zero or below, the percentage loses its illustrative meaning. In that case, the absolute capture price is often more informative.

The capture rate is also not a pure property of the technology. It does depend on the generation profile, but equally on demand patterns, the power plant fleet, fuel and CO₂ prices, grid bottlenecks, existing storage, import and export options and the market rules. An example: in a power system with high midday load, large battery storage and strong grids, the capture rate of solar power can turn out significantly different than in a system with rigid demand and limited lines.

Regional differences must not be overlooked either. In Germany, a uniform exchange price is formed for the entire bidding zone, while grid bottlenecks occur regionally. A capture rate based on the zonal price therefore does not show whether a plant relieves or burdens the grid locally. Redispatch, curtailment and grid connection conditions can change actual revenues and system costs without this being visible in a simple capture rate calculation. The official EEG market value even deliberately disregards curtailments in its extrapolation.

The capture rate makes the difference between energy quantity and market value visible. It shows that the timing of feed-in becomes economically more important the greater the share of weather-dependent generation. By itself, however, it does not explain security of supply, total costs or the technical integration of renewable energy. It becomes meaningful only together with load profiles, flexibility options, grid conditions, support rules and investment costs.

Sources

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Edited by eCMS on 11.11.2026 16:55

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