The Witznitz Energy Park has been built over the past two years on a former lignite mining site covering a total area of around 500 ha. in the municipalities of Neukieritzsch, Böhlen, and Rötha near the Hainer See. A 380 kV overhead line runs along the edge of the site to the Lippendorf lignite-fired power plant via the Pulgar substation. The solar plant was connected to this line via a new substation constructed by MOVE ON. The Energy Park was built in multiple phases and has therefore been injecting electricity into the grid since December 2023, but has only been working at full capacity for the past few weeks.
Stefan Kapferer, CEO of 50Hertz, said: “In the early months of this year, renewables covered around 75% of electricity demand in eastern Germany and Hamburg. The Witznitz Energy Park has already contributed to this, showing that the expansion of solar power is now moving to a whole new level. 50Hertz is a pioneer in integrating renewables into the power grid. By activating reactive power and incorporating the solar plant into our congestion management, we're once again doing pioneering work to make as much electricity from renewable energies usable as the grid will allow.”
For electricity to reach the consumer, reactive power is required as well as the actual active power. It acts as a kind of lubricant for transmission and is deployed to regulate individual grid sections depending on regional feed-in and offtake scenarios. Too much or too little reactive power has a destabilising effect on the standardised voltage. Up to now, the generators at large power plants have supplied reactive power when generating electricity, but it could also be requested by system management teams at transmission system operators (TSOs).
The Witznitz Energy Park will provide approximately 150 Mvar of reactive power, partially replacing the reactive power supplied by the neighbouring Lippendorf lignite-fired power plant (2 x 400 Mvar). This power can be activated even when the solar plant inverters do not convert direct current into alternating current and inject it into the grid. Instead, the power electronics built into the inverters will be supplied with electricity from the transmission grid to generate the reactive power. All this makes the Witznitz Energy Park a key pilot project for 50Hertz, and one from which other projects can benefit. As of 2026, an EU Directive on the internal electricity market will require TSOs to procure reactive power on the market through a tendering procedure. In late June, Ruling Chamber 6 issued a final ruling on a procurement concept developed for this purpose by the Federal Network Agency (BNetzA).
