The local public utility in Amberg, the Stadtwerke Amberg, in Bavaria has been supplying load-balancing energy since June 2016 using a combined heat and power (CHP) plant from MTU Onsite Energy. This helps the network operator deal with unforeseen frequency variations in the power grid.
Dipl. Ing. (FH) Wolfgang Hüttner from Stadtwerke Amberg said: “Our CHP plant has been feeding power into the public grid system for one and a half years now, also producing heat for the local district heating system. We're now able to supply also positive and negative balancing power. These extra sales are an attractive business proposition for us, and we're pleased to be able to contribute in this way to making the power grid more stable and, as a result, performing an important contribution to the energy turnaround.” The CHP plant is based on an MTU Onsite Energy 20V 4000 genset delivering around 2,000 kW of electrical power an approximately 2,200 kW of thermal energy.
MTU Onsite Energy and energy service provider EnerNOC are offering a joint solution to help genset operators run their systems more economically and market available balancing energy. Under this arrangement, MTU Onsite Energy CHP plants and standby gensets can be connected easily via an interface box to a virtual power plant. In that way they will help to balance out fluctuations in the power grid according to demand and availability.
Andreas Reisacher, Project Manager, Load-Balancing Energy at MTU Onsite Energy, explained: “We're offering our customers optimised, finely-tuned products for getting into the load-balancing power market. As well as lucrative incremental revenue for new and existing customers, this also provides a standardised process for hooking up MTU Onsite Energy gas-powered gensets (CHP plants) and standby gensets quickly to the EnerNOC control centre.”
Due to the gradual phase-out of conventional power stations in Germany and the expansion of renewable energies, it is becoming more of a challenge to keep the power grid at a constant 50 Hz. If more or less electricity is fed into the grid than the amount used, the grid has to be stabilized by means of load-balancing energy.
When the frequency has to be increased, power can be fed into the grid via the EnerNOC virtual power station (positive load-balancing). This can be provided, say, by standby gensets not constantly generating power. If the grid frequency is too high, the system can reduce the amount of electricity it feeds into the grid. This negative load-balancing is achieved by having bio-gas or natural gas-fired CHP plants reduce their otherwise constant output for short periods of time. Those operating MTU Onsite Energy CHP plants are now able to offer up to 80% of their rated power as negative secondary load-balancing power (instead of the customary 50%). Secondary load-balancing power must be supplied within five minutes.
Fabian Becker, Business Development Manager at EnerNOC, explained: “Operators stay in control of their plant and processes at all times. EnerNOC simply sends switching recommendations which can be accepted or rejected by the relevant controller on a case-by-case basis”. The energy service provider is marketing its system service on the German, Austrian and Swiss load-balancing power markets.