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Glossary · Energy industry & energy transition

Hybrid power plant

Hybrid power plant generation storage photovoltaics wind energy Electrolyser grid connection flexibility

A hybrid power plant is an electricity generation facility or a group of installations with several technical components that are operated together. These include, for example, wind energy, photovoltaics, battery storage, electrolysers or controllable loads. Spatial proximity alone is not sufficient for the term. What matters is the technical, economic or operational coupling of the installations. Typical features are a shared grid connection point, shared control and an operating strategy that coordinates generation, storage and conversion. There is no universally valid statutory definition of the term in Germany. However, funding law does recognise a narrowly defined special case with the plant combination (Anlagenkombination) in the innovation tenders.

The key parameters are the same as for individual installations. Generation installations are described by their electrical capacity in kilowatts or megawatts. A storage unit additionally has an amount of energy it can absorb, stated in kilowatt-hours or megawatt-hours. An electrolyser is described by its electrical input capacity. It does not generate electricity but consumes electricity to produce hydrogen. A single capacity figure therefore hardly describes a hybrid power plant. An example: 100 megawatts of photovoltaics, 60 megawatts of wind and a battery storage unit with 40 megawatts and 80 megawatt-hours. The storage unit can thus charge or discharge at full power for about two hours. This installation behaves quite differently from an installation with the same total capacity without storage. In addition, there is the grid connection capacity, which is often smaller than the sum of the installed capacities.

Distinction from related terms

A hybrid power plant differs from a virtual power plant primarily through physical coupling. A virtual power plant pools spatially distributed installations via communication technology and controls or markets them jointly. A hybrid power plant, by contrast, is usually linked through one site, one grid connection or shared infrastructure. The boundary is not always sharp. For classification, what counts is whether the coupling has repercussions on the grid connection, mode of operation and marketing.

A combined power plant (Kombikraftwerk) is also something different. In power plant engineering, the term usually refers to a combined-cycle gas turbine power plant. There, the waste heat of the gas turbine is used to generate additional electricity. In the debate on the energy transition, however, the term has also been used for groups of renewable installations. It is therefore worth looking at the respective context. A hybrid power plant in the current sense is less about the efficiency of an individual machine. The focus is on the temporal availability of electricity, the use of grid capacity and the response to market prices.

A solar park next to a wind farm is not, in itself, a hybrid power plant. It only becomes one when both installations are linked through shared technical rules, a coordinated metering concept, a shared feed-in limitation or joint marketing. The term is related to cable pooling, that is, the shared use of a grid connection by several installations. However, cable pooling describes only the connection side and not joint operational management.

Why the combination is technically relevant

Wind and solar installations generate electricity at different times. Solar power is produced only during the day, with a peak in the summer half-year. Wind power in Central Europe is often produced more strongly in the winter half-year and also at night. The two profiles do not complement each other perfectly, but usually better than two installations of the same technology. A shared grid connection is thereby used in more hours of the year.

A grid connection is scarce and expensive. It is designed for a maximum capacity, not for an annual quantity of electricity. A pure photovoltaic installation utilises its connection fully only in a few sunny hours. If wind or a storage unit is added, the same connection is used more often. The installed capacity can then be greater than the connection capacity. This is referred to as oversizing (Überbauung). If all installations generate a lot of electricity at the same time, part of it must be curtailed, stored or used on site.

In Germany, oversizing for installations under the Renewable Energy Sources Act (EEG) has been expressly regulated since the so-called Solarspitzengesetz of February 2025. Under § 8a EEG 2023, grid operators and plant operators can conclude a flexible grid connection agreement. It limits the maximum active power feed-in at the connection. The plant operator must be technically able to comply with this limit at all times. If installations or storage units of other operators are already connected at the same point of interconnection, their consent must be addressed. Grid operators are in principle not obliged to conclude such an agreement. In certain cases, however, they must examine this option. A deliberately planned curtailment of small amounts of energy can make sense if it allows a scarce connection to be better utilised.

Storage, electrolyser and flexible use

A battery storage unit in a hybrid power plant can absorb feed-in peaks and compensate for short-term forecast errors. It can also shift electricity to hours with a higher market value. It makes weather-dependent generation more controllable, but only over minutes to a few hours. For grid operation, this becomes relevant if the storage unit provides balancing power or responds to grid congestion and suitable rules and incentives exist for this.

An electrolyser serves a different function. It takes in electricity and produces hydrogen. This can be used as a material feedstock, stored or converted back into electricity. Reconversion to electricity makes sense only in certain cases because of high conversion losses. More often, the benefit lies in supplying industry, the chemical sector and refineries. In a hybrid power plant, an electrolyser can use generation peaks that would otherwise be curtailed. Economically, however, it usually needs many operating hours. Surplus electricity, by contrast, is available only at times. Whether the electrolyser relieves the grids or draws additional electricity in scarce hours depends on control, price rules, grid connection conditions and delivery obligations. The same applies to batteries that operate exclusively according to exchange prices.

Legal classification in Germany

The concept appears most clearly in the innovation tenders under § 39n EEG. The associated Innovation Tender Ordinance (Innovationsausschreibungsverordnung) applies until the end of 2028. There, only bids for plant combinations are admissible. A plant combination consists of several installations using different renewable energies or of installations with storage units. At least one component must be onshore wind energy or solar energy. In addition, the combination must feed in via a shared grid interconnection point. A storage unit may only take in electricity from the other parts of the combination. Its capacity must amount to at least 25 percent of the total capacity, and it must be able to store at rated power for at least two hours. Combinations without storage must be technically able to provide positive secondary balancing power for at least 25 percent of their capacity. Otherwise, the market premium does not apply. In the case of negative spot market prices, the entitlement to support falls to zero. These rules apply only to these tenders and not generally to every hybrid power plant.

Outside these tenders, separate rules on support, metering, grid connection and market role apply to each component. It is particularly important where a storage unit obtains its electricity. Under § 19 EEG, there are three options for temporarily stored electricity. Under the exclusivity option, the storage unit charges only renewable electricity. The delimitation option allows mixed operation, in which the share eligible for support is determined according to a determination by the Bundesnetzagentur. The flat-rate option is tailored to smaller solar installations. The chosen option affects settlement, guarantees of origin, eligibility for support as well as levies and charges. A shared grid connection thus simplifies lines and substations, but requires a precise metering concept.

Economic classification

Hybrid power plants respond to an electricity system in which generation profiles, market prices, grid capacities and land are becoming ever more important. With high simultaneous solar feed-in, photovoltaics often achieves low or even negative prices. A storage unit can increase the market value of generation if the price differences cover the costs of the battery, losses and ageing. A site with a good grid connection and land that can be permitted is valuable. Connection line, substation, metering, operational management and data connection can partly be shared. In return, the demands on planning and operation increase, because generation, storage and marketing are no longer decided independently of one another. Tender and support rules strongly shape the design. A technically sensible hybrid power plant can fail economically if market and grid rules do not reflect joint use.

Typical misunderstandings

  • Hybrid power plants do not guarantee security of supply. Combining wind and sun reduces fluctuations but does not eliminate them. Longer periods with little wind and little sun remain possible. Batteries bridge hours, but not weeks. Firm capacity requires further resources, such as dispatchable power plants, long-term storage, flexible demand or imports.

  • Hybrid power plants do not replace grid expansion. They use connections better and reduce local peaks. The transport of electricity from generation regions to consumption centres must nevertheless be handled by the transmission and distribution grids.

  • More components do not automatically mean more efficiency. A poorly sized battery costs a lot and is of little use. The quality of a hybrid power plant lies in the coordination of the components, not in the number of technologies.

Role in the future electricity system

As the share of renewable energies grows, it becomes more important when electricity is generated. Market value, residual load, grid congestion and controllable loads move to the foreground alongside the pure quantity of electricity. Hybrid power plants combine these levels in a concrete project. They can ease bottlenecks, make better use of infrastructure, reduce revenue risks and increase the flexibility of renewable installations. A hybrid power plant is not an energy source in its own right. It is most accurately described as a coordinated group of installations that generates, stores or converts electricity while pursuing a shared operational purpose.

Sources

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Edited by eCMS on 12.11.2026 05:10

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