Germany’s energy transition is entering a new phase. Many wind and solar power plants built in the 2000s and early 2010s are now reaching the end of their technical service life or are no longer eligible for EEG subsidies. This raises the question for operators of how existing sites can be used economically in the future.
For many wind and solar farms, “repowering” may be the answer.
What is repowering?
Repowering generally refers to the replacement of old, existing wind and solar power plants with new, modern technology. However, repowering not only involves replacing the equipment but also optimizing energy output.
This is because modern wind and solar power plants enable more efficient land use and create opportunities to make optimal use of existing grid connections. Repowering becomes particularly interesting in conjunction with so-called co-location concepts, in which renewable generation facilities are operated in tandem with battery storage systems at a single site. What initially appears to be a technical modernization can, in practice, develop into comprehensive site optimization.
When Old Wind Turbines Unlock New Potential
Technological advances in the field of renewable energy have been enormous over the past twenty years. While many older plants still produce electricity reliably, modern systems operate much more efficiently.
This is particularly evident in wind turbine repowering. New wind turbines have greater hub heights (i.e., the height from the ground to the center of the rotor) and significantly larger rotor diameters than their predecessors. As a result, they tap into stronger and, above all, more consistent wind conditions in higher layers of the atmosphere. At the same time, advances in aerodynamics, control technology, and system regulation ensure that more energy can be generated from every square meter of rotor surface area.
The result: Often, fewer turbines in the same area can generate significantly more electricity than the previous generation of wind farms.
Achieve Higher Efficiency Through Photovoltaic Repowering
The situation is similar with photovoltaic systems. While solar modules achieved efficiencies of about 15 percent fifteen or twenty years ago, modern modules often exceed 20 percent today. In addition, operators benefit from improved low-light performance and bifacial technologies that can also harness reflected light. This not only increases the installable capacity per unit area but often also boosts the actual energy yield.
More Performance in Less Space
However, the added value of repowering lies not only in higher electricity output. Modern plants often require significantly less space to generate the same amount of power.
A simple example illustrates the potential: An existing solar farm with a capacity of 6 megawatts peak (MWp) could occupy about 9 hectares of land if it uses older modules. If these modules are replaced with modern technology while maintaining the same capacity of 6 MWp, the required land area is reduced to about 6 hectares. This frees up about one-third of the land.
These newly available spaces open up entirely new possibilities. Instead of remaining unused, they can be used, for example, for battery storage, additional transformers, or other grid infrastructure. This is precisely where the connection between repowering and co-location begins.
Why Battery Storage Is the Logical Next Step
The combination of repowering and battery storage is increasingly viewed as a natural next step in the development of existing power plants. The reason for this lies in the infrastructure that is already in place.
Today, a grid connection point is one of the most valuable components of an energy project. Obtaining new grid connections is becoming more difficult and time-consuming in many places. In a repowering project, however, the grid connection already exists. At the same time, modernization often frees up space. This means that two of the most important prerequisites for a battery storage system are already met.
An additional battery storage system can also significantly improve a site’s cost-effectiveness. Modern wind and solar power plants generate more electricity than their predecessors and, as a result, experience high power peaks more frequently. Instead of feeding this energy directly into the grid during periods of low or even negative electricity prices, it can be temporarily stored and sold at a more economically favorable time.
Co-location as a Holistic Site Concept
The advantage of co-located battery storage is that a site is no longer viewed in isolation as a wind farm, solar farm, or battery storage facility, but rather as an integrated energy system.
For example, higher-efficiency solar modules can be operated in conjunction with a battery storage system and a charging infrastructure for electric vehicles. This opens up interesting additional revenue opportunities, particularly for PV repowering projects. Local charging stations can directly use the solar power generated and, under certain conditions, generate additional revenue through the so-called GHG (greenhouse gas reduction quota) premium.
This transforms a traditional solar park into a multifunctional energy and mobility hub. The existing grid connection is used more efficiently, while new business models emerge at the same time.
Conclusion: From Repowering to Site Optimization
Repowering is much more than simply replacing old wind or solar power plants. Modernizing existing sites creates ideal conditions for integrating additional technologies, such as battery storage, into a holistic co-location concept. Vacant land, existing grid connections, and more efficient power generation facilities together form the foundation for a new generation of energy projects.
Anyone considering repowering today should therefore look beyond just the power generation facility. The opportunity lies in rethinking the site as a complete system. This is because the greatest added value often comes not from replacing individual components, but from the intelligent combination of generation, storage, and consumption. Co-location is thus evolving from a technical trend into a crucial building block of a successful and economically viable energy transition.
