Public Service

VPP public utility VPP public utility Public utilities as participants in virtual power plants? What sounds unusual is now common practice. After all, municipal utilities also have a great deal of flexibility that can be put to good use by means of digital networking and short-term electricity trading through virtual power plants. In January 2012, Stadtwerke Groß-Gerau Versorgungs GmbH (GGV), a local utility in the west of Germany close to Frankfurt, was the first municipal utility to join the virtual power plant network of Next Kraftwerke.

The cooperation began with the integration of GGV's biogas plants into the virtual power plant Next Pool. However, the cooperation soon expanded to other areas. "Due to limited internal personnel resources, we were looking for a market partner with whom we could optimise our electricity procurement costs. Based on our previous cooperation, the choice of Next Kraftwerke was obvious," explains Paul Weber, Managing Director of GGV. Today, in addition to the integration of all of GGV's renewable energy plants, the joint project includes balancing group management and portfolio management for the utility's day-to-day operations.

In portfolio management, Next Kraftwerke is responsible for forecasting generation and load (household as well as C&I consumers) for GGV's balancing group in close cooperation with GGV. Next Kraftwerke then transmits the forecast schedules to the transmission system operator daily in schedule management and trades the reported quantities in day-ahead trading on the EPEX spot exchange. The balancing group of GGV is then smoothed in the event of forecast adjustments through intraday trading on EPEX in order to reduce balancing costs and to comply with the obligation of quarter-hourly balancing group management.

What are the results of the cooperation? Paul Weber takes stock: "Thanks to the good and trusting cooperation at eye level, we reduce our electricity procurement costs without having to invest in our own trading department. Added to this, of course, are the smooth renewables trading and the participation in the balancing energy market with our dispatchable renewable electricity generation plants. The decision for this type of cooperation was easy, as Next Kraftwerke also assumed balancing risks associated with portfolio management and feed-in forecasts. In the medium term, we would like to expand the cooperation, especially with regard to the flexibilisation of our bioenergy plants and the procurement of electricity via short and long-term electricity markets."

Facts & Figures

Transported electricity on mid- and low-voltage grid:150 GWh p.a.
Power production from renewable sources:12 GWh p.a.
Applied products:Market Premium Model, Balancing Energy, Portfolio management, Power Trading, Balancing group management