The electricity grid is under pressure. This is true both in Denmark and abroad. Capacity is limited, making it difficult to connect new green energy sources, such as wind or solar power plants, to the wider electricity grid. For some Danish projects, the message has been that, even though they have been politically approved and are ready for installation, they cannot expect to be connected to the electricity grid until well into the 2030s.
This is, of course, a major obstacle to the green transition, where an increasing number of sectors in society are working towards electrification and therefore require renewable energy. The lack of connection capacity is due to the limited capacity of the electricity grid, which is already reserved for existing facilities, whilst expanding the grid is both time-consuming and expensive.
Existing facilities utilize only a limited portion of the allocated grid capacity. Until now, electricity network operators have been obliged to utilize all the renewable energy that, for example, a wind power plant can produce. This rule means that a 100MW wind power plant takes up 100MW of grid capacity. However, full capacity is only utilized when wind speeds are high. Wind power plants typically operate at full capacity between 20% and 50% of the time, depending on their location, and solar power plants operate at even lower capacity factors, typically between 15% and 30%. However, capacity is still reserved in the electricity grid to prevent overloads.
There is therefore great potential in new technologies such as hybrid power plants, which combine different green energy technologies and manage them so that the grid is NEVER overloaded beyond its allocated capacity.
Although hybrid power plants sometimes must reduce renewable energy production to keep it below grid capacity, they remain economically attractive, both for electricity companies, which can better use the grid, and for owners, who can connect more renewable energy more quickly.
Hybrid power plants can secure more green energy sources
So, what exactly can a hybrid power plant do?
A hybrid power plant uses wind turbines, solar panels, and batteries, possibly supplemented by electrolyzers that convert electricity into hydrogen. Hybrid power plants already exist abroad, for example, Kennedy Energy Park in Australia, which is the world’s first hybrid power plant and has been operational since 2024 with 43 MW of wind capacity, 15 MW of solar capacity, and a 2 MW/4 MWt battery. In Denmark, permission was granted for several hybrid power plants in 2025. DTU also has a small pilot plant, Risø HPP, which currently consists of 450 kW of wind capacity, 325 kW of solar cell capacity, and a 250 kW/1,155 kWh battery.
A hybrid power plant offers the advantage of providing multiple services. Firstly, it can, of course, supply renewable energy – and, importantly in this context, it never supplies too much energy, but can regulate the amount so that the electricity grid is not overloaded.
In addition, hybrid power plants can provide the electricity grid with a wide range of so-called ancillary services, which have traditionally been supplied by power plants that have been replaced by wind and solar power plants. Grid operators need these ancillary services to ensure a robust and stable electricity supply when operations do not run as planned, for example, due to faults in the grid or at a power plant.
In this regard, hybrid power plants are better equipped than stand-alone wind power plants or solar power plants to provide ancillary services. For example, the battery can provide a boost if a power plant or a submarine cable goes out of service due to a fault. In some cases, a single fault can trigger further faults, and the situation can become so serious that the electricity supply shuts down completely. For example, the Iberian Peninsula experienced a power grid black-out last year that affected 60 million people. Hybrid power plants can both reduce the risk of such a disaster and, if it does occur, help restoring the supply so that consumers experience a shorter period without power.
The green transition can thus be strengthened by more hybrid power plants. Both because they can help integrating more green energy sources without overloading the electricity grid, and because they can provide ancillary services. For example, a plant comprising 100 MW of wind, 80 MW of solar, and 50 MW of battery capacity might be connected with a grid capacity of 100 MW and still be profitable for the owner, depending, of course, on electricity market prices.
When the hybrid power plant can also provide ancillary services during periods of high demand, it becomes possible to reduce the operation of older power plants, which currently serve to ensure the stability of the electricity grid. And some of which are still powered by fossil fuels.
In other words, a true win-win-win situation where everyone benefits. Owners of green energy sources, owners of the energy grid, and society as a whole.
Risø HPP can enhance research and development – in collaboration with businesses
We have established Risø HPP because new solutions must continue to be developed and tested. Our research focuses on both developing solutions to increase the value of renewable energy for owners and the electricity grid, and on developing and testing new ancillary services to maintain a high level of security of supply. With Risø HPP, we can test these solutions in both realistic and controlled conditions before they are introduced into large commercial hybrid power plants, which are typically more than 100 times the size of Risø HPP.
These may be solutions that form part of a research project, or solutions developed by companies wishing to incorporate them into their customer offerings. Risø HPP is also open to companies that need to have commercial solutions tested.
Finally, part of our research focuses on determining the optimal mix of wind, solar, and battery capacity in hybrid power plants that delivers the strongest economic business case. To this end, we have developed a software platform called HyDesign. There is already interest from major energy companies in hybrid power plants, but it must, of course, also be profitable for them to invest in these solutions.
In conclusion, there is a great potential for hybrid power plants, both for accelerating the expansion of renewable energy and for ensuring a stable electricity supply as the share of renewable energy increases. This is important for national security of supply, but the really big picture is, of course, the global potential for hybrid power plants.
