Research Projects

A consortium of European grid operators, energy suppliers, manufacturing companies and research institutes aimed at tackling the challenge of integrating more wind energy into the electrical transmission system. In one of the project demonstrations, Fraunhofer IEE (formerly Fraunhofer IWES) developed innovative solutions for these challenges, in collaboration with DONG Energy (Danish energy supplier), Energinet.dk (Danish transmission system operator) and Red Eléctrica de España (Spanish transmission system operator).

In this demonstration, a »virtual power plant« aggregated flexible electric consumers (e.g. cold storages) and renewable generators (e.g. wind turbines) through a central IT system, which optimized their joint behavior. DONG Energy developed the hardware and software solutions of a real life virtual power plant demonstration in Denmark. Fraunhofer IEE supported this development through diverse research activities. The main results of these research activities can be summarized as follows:

1. Analysis of technical and regulatory barriers

• Identification of technical and regulatory conditions, which are needed to optimally enable virtual power plants and decentralized energy units to join markets for energy and ancillary services
• With regard to this, recommendations have been made to change existing market regulations, in particular:
• Shortening the lead time and bid duration of products on frequency reserve markets, as well as separating the procurement of positive and negative balancing energy
• Cost-benefit analysis of reactive power provision by decentralized generators, to aid the development of a possible future market for this ancillary service

2. Evaluating the potential of decentralized units for providing reactive power:

• Simulations of a realistic Danish power grid demonstrated that decentralized production units (e.g. wind turbines) can offer significant amounts of reactive power to the transmission system operator, as a means to stabilize the voltage. The results strongly depended on the investigated grid and the payment structure. It was also shown that reactive power from these units, if controlled by a virtual power plant, can be a cost-efficient alternative for the grid operator, to buying conventional reactive compensation units
• Similar investigations on a generic German network led to comparable findings
• With the aid of a novel real-time simulation, it was shown how reactive power provision by a virtual power plant could be utilized in an energy system with multiple actors

3. Transferability of the virtual power plant concept to Germany:

• The transferability of the Danish virtual power plant demonstration to Germany was assessed through energy-economic simulation studies. In the German scenario, it was shown that a flexible virtual power plant can respond to fluctuating power generation by renewable sources:
• Due to this response, electricity prices can be decreased and security of supply improves. Hence a large-scale virtual power plant can have a substantial positive influence on the energy market and thus leads to an improvement for society as a whole

4. Control reserve provision by wind farms:

• The provision of control reserves by wind farms was demonstrated on a technical level
• The effects on society, due to wind energy producer’s participation on the control reserve market in Germany, were assessed
• A prerequisite for successful reserve market participation is the adjustment of the regulatory framework
• The expected cost reductions of reserve provision, due to wind farms joining this market, can exceed 20%