Hybrid photovoltaic power plants

Between 2023 and 2024, solar installations will account for three quarters of newly installed power generation capacity worldwide. In 2015, the global installed capacity of photovoltaics was approximately 200 GW; in 2024, the generation capacity will increase tenfold to 2,000 GW - reaching the two terawatt mark.

The International Energy Agency estimates that approximately 6,000 GW of PV capacity will be installed by 2030, a further tripling in just a few years. The almost exponential increase in RES capacity requires flexible and intelligent integration into the energy system.

An important part of the answer to the integration challenge will be the combination of generation and energy storage on the same site. In the near future, the combination of free-standing solar installations and storage systems will be the new norm - a trend already observed in the German residential storage market.

Significantly lower prices compared to the past
A key driving force behind the widespread boom in hybrid projects is the virtually falling prices of components. Photovoltaic components are now 85% cheaper and battery storage systems are even 90% cheaper than 15 years ago.

According to a study by the Fraunhofer Institute for Solar Energy Systems (ISE) published in July 2024, the total cost of electricity (LCOE) for German solar farms ranges between 4.1 and 6.9 cents/kWh. When combining free-standing PV with battery storage systems, the LCOE ranges between 6.0 and 10.8 cents/kWh.

The production costs of fossil fuel power plants are now significantly higher. Electricity from lignite-fired plants costs 15.1 to 25.7 cents, from coal-fired plants 17.3 to 29.3 cents, from CCGT plants 10.9 to 18.1 cents, and from flexible gas-fired plants 15.4 to 32.6 cents per kilowatt-hour. Electricity from nuclear plants costs 13.6 to 49.0 cents/kWh.

This shows that we save a lot of money with hybrid power plants in addition to protecting the environment. In the long term, they will guarantee low electricity prices for industry, small and medium-sized enterprises and households.

Hybrid power plants and grids
The trend for hybrid power plants will be boosted by the global boom in battery storage. Battery storage systems can help optimise the marketing of green electricity through different business models such as feed-in tariffs or direct marketing.

Batteries also enable energy arbitrage, i.e. storing electricity when prices are low and feeding it back into the grid when demand - and therefore prices - are high, as well as operational reserve and grid stability services. In the future, the grid stability services provided by hybrid power plants will contribute significantly to increasing grid stability and flexibility. Intelligent control concepts and processes will allow them to switch between operating modes to achieve the ideal balance between profitability and ability to serve the grid.

Maximum utilisation
Grid connection locations are often a limiting factor when it comes to PV and wind deployment. Contrary to current practice, they could be used to connect more generation capacity than they are actually capable of transmitting.

Such overbuilding of RES capacity would make sense for hybrid plants, as the generation profiles of PV and wind are very different and in fact complementary. By connecting both solar and wind generation and building 250% more, the capacity utilization of the grid connection point could increase to 53%.

In contrast, PV-only plants have an average utilisation rate of 13 per cent and wind-only plants 33 per cent. The German Renewable Energy Association describes this approach as "low-efficiency sources".