Smart Grid - energy distribution and network control

Bundled energy through virtual power plants

Virtual power plant projects in North Rhine-Westphalia and Munich
The turnaround in energy policy sees the rebuilding of the German energy system in a context that to this point does not have any examples to draw on and which is being carried out at unprecedented speed. The challenges involved in implementing the new system are great. In order for the turnaround in energy policy to be a success, fundamental adjustments to the economics of the current energy system are required. This includes the conversion of existing power supply networks to a smart grid, a process in which virtual power plants play an important role. Together with Siemens, RWE and Stadtwerke München have successfully implemented the first projects.

A virtual power plant bundles decentralized energy resources (producer, storage and consumer) whose operation of an dezentralized energy management system is jointly planned, optimised and monitored. The bundled output can be offered to the European Energy Exchange in Leipzig or other markets. Virtual power plants also increase grid stability because they can provide a controlling power range

The village of Niederense in the Sauerland region offers many hiking trails. With tranquillity, chirping birds and the Möhne river, it embodies pure nature. The river power plant which was built in 1913 has long been a part of this area. With 215 kilowatts of power, it is one of the smaller hydroelectric power plants in the Sauerland region. Siemens-Halske generators have tirelessly generated electrical power here for 100 years. In October 2008, the “sprightly seniors” experienced a renaissance: to kick off the “virtual power plant” (ProViPP, Professional Virtual Power Plant) project of RWE and Siemens, the systems were connected together with eight other hydroelectric plants belonging to Lister and Lenne in the Sauerland region in order to operate and use them in a more efficient and economical manner.

Strictly speaking, a virtual power plant is a bundle of distributed energy sources (producer, storage and consumer) whose operation is jointly planned, optimised and monitored by an decentralized energy management system. If integrated into a smart grid, a virtual power plant can thereby open new possibilities to power utilities and operators of power generation units because the bundled electrical power can be offered to the European Energy Exchange in Leipzig or other markets. This gives the producer more flexibility. In addition, virtual power plants contribute to grid stability because they can provide controlling power in the minute reserve. They are also ideal for renewable energy sources. Since the amendment to the Renewable Energy Act in January 2012, the market premium model has given an incentive to directly sell electrical power from these systems to the energy markets. Virtual power plants thereby present new opportunities for municipal energy providers. Furthermore, they are likely to gain importance in a smart grid in the wake of the turnaround in energy policy.

Since early 2012, RWE has marketed its virtual power plant – created through the merger of the river power plants in the Sauerland region – to the energy exchange in Leipzig. In addition, Siemens and RWE signed a framework contract and agreed to expand the combined output to 20 megawatts (MW) in the first year of operation after the pilot phase. By 2015, more power plants are to join the virtual network with the aim of producing several hundred MW. Potential members of the virtual power plant include biomass plants, biogas combined heat and power generation units, wind turbines and hydroelectric power plants throughout Germany. The project is very successful, as today’s overall output of the systems in the network is at 300 MW – well beyond what was originally planned.

Similarly to RWE, Stadtwerke München (SWM) also bundles six of its combined heat and power units, five hydroelectric power plants and a wind turbine from its Munich-based coverage area into a virtual power plant for the purpose of operating them in a more efficient and economical manner. The merger of the dispersed systems into a virtual power plant is currently producing a total output of 20 MW.

The brain of the virtual power plants belonging to RWE and Stadtwerke München is the decentralised energy management system (DEMS) from Siemens. It uses sophisticated information and communication technology to network and bundle the individual decentralized power producers for the purpose of centrally controlling them. The system processes all of the important information such as weather forecasts, current electricity prices and the demand for energy. With this data, the system creates and monitors a deployment plan for all of the integrated systems. Energy consumption is predicted every hour as depending on weather forecasts and the type of day that it is. The operation schedule minimises the production and operating costs of the systems in the virtual power plant network and maximises their economic benefits. The system not only takes economic aspects into account, but ecological factors as well.

As part of the turnaround in energy policy, the next few years will see the number of decentralized power generation units rise – especially in relation to renewable energy sources. The need for environmental protection and resource conservation as well as the increase in energy efficiency reinforces this trend. Increasingly bundled into virtual power plants, decentralized power generation units will contribute to the successful transformation of this country’s energy system.

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contact details/company:
Siemens AG
Division Smart Grid
Gugelstraße 65
90459 Nuremberg

contact person:
Dr. Thomas Werner