Driving innovation with a combination of solar and battery storage

Hybrid renewables are playing a key strategic role in decarbonising the energy industry. Energy storage technology has a particularly big impact on optimising our use of renewable energy sources.

In Germany, government Innovation Tenders encourage projects aimed at diversifying the country’s energy share. BayWa r.e. secured funding through the first of these tenders to develop a number of sites which both produce and store temporarily solar power. One project in particular, near the town of Pfaffenweiler, was among the federal state’s first to combine ground-mounted PV and battery storage systems.

The hybrid plant will feed solar electricity direct to the grid or shift the energy to hours when demand and prices are high. In addition, the project provides ancillary services supporting stable operation of the electricity system. It’s a versatile energy solution where many measures for the conservation and promotion of biodiversity are also implemented.

This means for example rock fills and deadwood piles, creating habitats for lizards and other small animals. It also includes flowering islands which have a positive effect on neighbouring agricultural land, nesting boxes for birds and the multiple use through sheep grazing. These measures to promote biodiversity are a convincing argument for hybrid projects as part of the German energy mix, in addition to their importance for the energy industry.

The advantages of hybrid plants don’t come without challenges. Connecting and co-operating two technologies together involves more than detailed knowledge about each technology. For the integration of a hybrid system both technologies are influencing the operation of each other. The cooperation between the technology specialists as well as the support of a connecting party is key.

The operation of a hybrid power plant requires a more complex park controller and monitoring system setting than a non-hybrid plant. That’s why we focused on early involvement of all the parties including the energy trader and the plant operator. Special rules and regulations must be followed when a hybrid power plant is subsidized through the German innovation tender which poses additional challenges to the park controller.

Another challenge to overcome was in meeting the requirements of the Innovation Tender itself. The site could only temporarily store power before feeding it into the grid on a strict time delay. Spitalhöfe Solar Park fulfils this: it helps to relieve the grid directly at peak generation times. However, in the evenings and early mornings, or less sunny periods, it contributes with stored energy.

Thanks to the high standard of cross-technology expertise spread across our teams, we were able to successfully realise the project.

The 8-hectare Spitalhöfe Solar Park in Pfaffenweiler entered operation in May 2022. Now, its 7.3 MWp of installed capacity is generating around 8 million kWh of green electricity per year. That’s about enough to power 2,500 three-person households.

Alongside the sites at Deisenhausen and Kreuth, Spitalhöfe Solar Park is one of three hybrid projects completed through the Innovation Tender. In total, they boast a solar capacity of about 42 MWp and 41 MWh of battery storage capacity.

This outcome demonstrates our unique expertise in hybrid solutions, which we expect to become the new normal in the development of renewable energy plants. They’re not simply a cost-effective way of meeting key challenges to energy grids all over the world. With good planning, they also offer a wealth of opportunities to foster biodiversity and exist in harmony with the surrounding area.

For the Solar Park Spitalhöfe in Pfaffenweiler our Energy Trading experts have developed a holistic marketing concept. The power produced is marketed via secured price hedging with a five-year Power Purchase Agreement (PPA). Additionally, the battery energy storage systems (BESS) is the first within the German Innovation Tender to be prequalified as a balancing energy provider by the German transmission system operators. By marketing the power on the balancing energy market, we can optimise battery revenues and stabilise the electricity grid at the same time.

Our operations and maintenance team care for the site 24/7, with inhouse service technicians on-site for regular preventative works. Having conceptualised and constructed it, we’re still here making sure the site is fit for the future.