The Happurg pumped storage power plant in the Nürnberger Land district has been shut down for 13 years. At the beginning of 2011, the upper pool was emptied after massive damage to the pool floor was discovered. After much back and forth, the energy supplier Uniper is now set to make a decision about the future of the plant – there are many indications that it will be positive. “In anticipation of approval and a positive investment decision, Uniper is already investing money today and is pushing the project to the point where it is ready for a decision as quickly as possible,” says a company spokesman. “The final decision will only be made in the coming months.”
The Happurg pumped storage facility is one of seven such systems in Bavaria. With an output of 160 megawatts and a storage capacity of 840 megawatt hours of electricity, it is one of the largest. Like all pumped storage, it works according to the same, approximately hundred-year-old technical principle: If more electricity is available than is needed, the water is pumped from a river, lake or artificial storage – in Happurg’s case this is the Happurger See – using electric pumps pumped through pipelines a few hundred meters upwards into the so-called upper basin. The one for the Happurg facility is located on the 586 meter high Deckersberg. If electricity is needed, the water from the upper basin is directed down to turbines and generates the amount of energy you need. The fall height of the pipes of the Happurg pumped storage facility is a good 200 meters.
Pumped storage is not just technologically proven large-scale electrical storage. From the perspective of their followers, they have a number of important additional advantages. They can be controlled very precisely, meaning that fluctuations in the power grid can be compensated for to the second. You can start their turbines without electricity by directing the water from the upper basin over them. This is important for getting the power supply back on track after a total failure. And with an efficiency of 80 percent or more, they are considered very efficient. When the water is pumped up, a maximum of 20 percent of the electricity used is lost.
The Happurg pumped storage facility was connected to the grid in 1964 after a four-year construction period and was in operation until the beginning of 2011. In January 2011, measuring devices at the upper basin sounded the alarm. The operator at the time, Eon, stopped operating the power plant and had the upper basin drained. Exploration revealed collapses in its sole, which resulted from a filled cave system beneath it. Eon soon set its sights on renovating the upper basin; it was originally hoped to be able to bring the system back online at the end of 2013.
But then the work was delayed from year to year, the operator Eon became Uniper in the meantime and the energy scene was left guessing what would become of the power plant. The reasons for the long uncertainty are said to have been, among other things, that the original renovation concept turned out to be extremely complex and too expensive. In addition, the Uniper spokesman also criticizes, there is currently a lack of “appropriate remuneration” for the contribution of pumped storage to the stability of the power grid and other services. They are financed exclusively through the fees for the electricity they produce. This apparently made a complex renovation of Happurg less attractive.
Nevertheless, state politicians repeatedly campaigned for it. Economics and Energy Minister Hubert Aiwanger (Free Voters) explained during a visit to the facility six months ago: “We need these large storage systems; they are an important component of the energy transition.” The federal government must now create the framework conditions so that their services are “economically worthwhile”. The Green Party member of the state parliament and energy expert Martin Stümpfig, who comes from Franconia, has also always advocated the renovation of Happurg.
Especially since the storage requirements for Bavaria are gigantic. The Bavarian Energy and Water Industry Association (VBEW) has recently pointed this out. According to VBEW managing director Detlef Fischer, there is currently a “real expansion boom in battery storage”. According to VBEW, there are now 230,000 stationary storage systems connected to the network across Bavaria, the lion’s share of which are home storage systems for private photovoltaic systems. “Approximately 70 percent of new photovoltaic systems on buildings are equipped with battery storage,” says Fischer.
However, the range of Bavarian battery storage is still extremely limited. In purely mathematical terms, the power supply in the Free State could be maintained for just 17 minutes in the event of a widespread failure – according to Fischer. If you add the capacity of the existing pumped storage, the bridging time would double to just 34 minutes. A dark lull in which neither solar nor wind power is available for several days could “not even begin to be overcome” with the existing storage capacities, says the VBEW man.