Virtual power plant

This article deals with the interconnection of power plants to form a system that ideally behaves like a conventional power plant. For the simulation of power plants see power plant simulator .

A virtual power plant is an interconnection of decentralized power generation units, such as photovoltaic systems , hydropower plants , biogas , wind energy plants and combined heat and power plants . This network provides electrical power reliably and can thus replace power from large power plants that is independent of the supply.

The term virtual power plant refers to the amalgamation of several locations - but not to the fact that no electricity would be generated by them. Other common terms are combined cycle power plant , swarm power plant and DEA cluster (= cluster of D ezentralen E rzeugungs a NNEXES). An important aspect of virtual power plants is the marketing of electricity and the provision of system services from a network of small decentralized systems.

A virtual power plant made up of many individual systems

Virtual power plants are associated with costs for communication and the effort of central control. Both visions of a future power supply and existing business models are combined under the buzzword virtual power plant.

Generator network

If generator networks and load networks are interconnected, an intelligent control system can first try to compensate for power peaks as far as possible by means of load control on the consumer side, in order to then cover the remaining power requirements cost-effectively from the offer of the connected generator networks.

Virtual power plants use synergies that are made possible by the interconnection of individual power plants . Additional generators can be added to distribute the load as soon as peak loads occur that would overwhelm a single power plant. Disadvantages that arise from a special location or the changeable weather can be compensated. Base load power plants such as B. Nuclear and lignite power plants are not shut down at night for economic reasons, which is why the intermediate storage of night-time electricity in storage power plants is already state of the art.

If you combine, for example, a wind park , a photovoltaic power plant and an energy storage device, such as a pumped storage power plant , to form a virtual power plant, the solar power plant can step in when there is calm. If there is no sun, the wind power plant can deliver. When the sun is shining and the wind is blowing, excess energy can be fed into the pumped storage facility. If there is no wind and no sun shining, the pumped storage plant supplies the energy back. The more power plants and types of power plants are combined, the higher the synergy effect and thus the overall efficiency of the virtual power plant.

Functional diagram of a CHP system

To the extent that micro-combined heat and power (MKWK) for the energy supply of buildings is gaining ground, coupling to a virtual power plant is becoming more and more obvious here , because peak load electricity and balancing energy can be generated through coordinated feed-in behavior , which has economic advantages throws off. Currently available CHP Plants for the buildings energy supply in the composite already meet the technical requirements for the provision of control power, provided by the control area manager. A mini-cogeneration unit can produce electricity mainly when the network load is peaking and buffer the excess heat in a heat storage system . For this purpose, however, the owner of a decentralized system must allow the operator of the virtual power plant to intervene in the control of his system, something that private households in particular are reluctant to accept.

technical basics

Because there are not yet sufficient small-scale energy systems that can be operated economically and because communication also has to be carried out between the electricity feed-in nodes and the control center, setting up virtual power plants through their connection initially encountered major hurdles. Therefore, research and development was carried out in the following areas:

• Communication layer ( WAN technologies that minimize operating costs such as powerline and ( radio ) ripple control , etc.)
• Message standardization
  • Performance requirements: amount of energy, probable duration, latest possible delivery;
  • Demand for performance: amount of energy, probable duration, maximum possible downtime;
  • Range of services: amount of energy, expected duration, estimated costs, etc.
• Communication protocol (preferably an asynchronous, asymmetric, event-driven protocol).

standardization

Projects funded by the European Union such as B. DISPOWER, FENIX and MICROGRIDS develop standards for uniform information and communication technology in this area. With these standards, both the internet-based control of a virtual power plant and the automated trading of electricity are possible. It is becoming apparent that the expansion of the communication protocol IEC 61850-7-420 will become the control technology standard for decentralized energy systems.

Since the revision of the Renewable Energy Sources Act in 2014, all direct marketing systems must offer the option of remote control.

Situation in Germany

Direct marketing

An already existing business model in this sense are the service providers for the direct marketing of EEG systems d. H. of wind, solar, geothermal, biomass and other power plants that are entitled to remuneration under the Renewable Energy Sources Act (EEG) .

background

The regulations of the EEG provide that such systems are marketed on the spot market. In addition to the revenues on the spot market, the system operators are entitled to a surcharge that compensates for the difference between the spot market revenues of an average system in the relevant category and a fixed guaranteed price for this system category (market premium, Section 20 EEG). Thus, EEG plant operators are obliged to participate in electricity trading , although their feed-in is very difficult to predict and the feed-in schedule does not reach tradable product sizes even for many of the plants concerned. By participating in electricity trading, the systems are also subject to the regulations of balancing group management , which provide that binding quantities are traded on the electricity market and unplanned deviations are offset against balancing energy. For the typical operator of EEG systems, participating in electricity trading is therefore associated with undesirable risks.

Business model

The business model of direct marketers consists of bringing together third-party EEG systems for participation in electricity trading in their own balancing group. The generation of the combined portfolio of EEG systems is then forecast as a virtual power plant and marketed on the electricity market. Unpredictable deviations from individual feeders partially offset each other. It is also economical for a large portfolio to invest in professional forecasts. Short-term load forecast adjustments from changes in wind or solar forecasts result in more tradable sizes on the intraday market, even for a large portfolio. The marketer switches off systems via appropriate technical infrastructures if the spot price on EEX is negative. As part of the business model, EEG operators are offered a fixed price in euros / MWh. The marketers assume all risks associated with marketing from the randomness of the feed-in profile, the short-term markets and the balancing energy market.

providers

Providers of the business model described are, for example, Statkraft, Clean Energy Sourcing, Energy2Market, Next Kraftwerke, E.ON and in.power.

Balancing energy pools

Another existing business model is the amalgamation of smaller systems for the provision of control power . According to a resolution by the Federal Network Agency, the transmission system operators were obliged to also allow balancing energy pools to be offered at the balancing power auction. This business model is attractive for a wide range of generation plants, as the typical CHP plants of the municipal utility do not meet the requirements for participation in the control reserve market on their own. Furthermore, within the framework of such pools, flexibilities of load acceptance for the regular markets can be developed. As part of the pool model, available short-term flexibilities of many power plants and industrial customers can be bundled in a "virtual power plant". The pool provider receives the electronic call from the network operator for the provision of a defined start-up or shutdown profile and implements this technically in his virtual power plant. The economic side is regulated through profit sharing agreements with the pool participants.

Providers of control energy pools are, for example, MVV, Clens, Entelios, Next Kraftwerke Trianel and Ompex in Switzerland.

Research projects

The Fraunhofer Institute for Wind Energy and Energy System Technology (IWES), together with nine partners from business and science, investigated in the three-year project "Combined Power Plant 2" how to achieve electricity supply safely and reliably with renewable energies alone . In models and field tests, wind and biogas power plants as well as solar power plants were linked and controlled centrally as a virtual power plant. The researchers hoped to gain knowledge of how the increasing share of wind and solar energy can be integrated into the power supply. In addition, it should be examined what contribution renewable energies can make to the quality of supply. As a result, it was established in August 2014 that grid stability can be ensured in a completely renewable power supply. A field test in which several wind farms, biogas and photovoltaic systems with a total output of over 80 MW were combined, demonstrated how a network of renewable energy systems can provide control power and so-called system services and contribute to the stability of the power supply.

Studies by TU Berlin and BTU Cottbus have shown that intelligent networking of decentralized regenerative power plants can make a significant contribution to optimally feeding large amounts of fluctuating electricity into the supply network. The studies also showed that with the help of suitable control, electricity demand and production in a large city like Berlin can be well coordinated. This can both relieve the higher network level and significantly reduce the need for conventional reserve capacities.

“A complete switch to renewable energies is inevitable for reasons of climate protection and in view of finite fossil resources. The question is what that means for the current structure of the power supply, for transmission networks and energy storage, ”said Dr. Kurt Rohrig, Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) at the Kassel location . "Our practical test will show that a full supply with renewable energies is realistic and that the lights do not go out even when there is calm".

See also

• Decentralized power generation
• Demand side management
• Network parallel operation

literature

• Droste-Franke et al .: Fuel cells and virtual power plants . Springer-Verlag, Berlin 2009. ISBN 9783540857969
• Fraunhofer IWES: Research Project Combined Power Plant 2nd Final Report 2014 ( Link )
• Denne: Chances and possibilities of a virtual power plant: using the example of the Saerbeck climate municipality . AkademikerVerlag, Saarbrücken 2015. ISBN 978-3-639-87282-8

Web links

General

• The regenerative combined power plant
• Background information from the Renewable Energy Agency
• Virtual Power Plants: Theory or Reality? (PDF file; 445 kB)
• Telepolis at Heise.de: The virtual power plant
• Playful simulation of a virtual power plant at Next Kraftwerke
• Interactive graphic on the technology of a virtual power plant at Next Kraftwerke
• SESAM: Self-organization and spontaneity in liberalized and harmonized markets
• Requirements for decentralized feeders with regard to operational management in virtual power plants (2006) (PDF file)
• The RegenerativKraftwerk Bremen at Energie & Management (March 2011) (PDF; 1.4 MB)
• Virtual power plants. Wind power in the boiler Article in the FAZ

Pilot projects (R&D)

In pilot projects , the economic efficiency and the possibility of reacting flexibly to load fluctuations are examined:

1. The regenerative combined power plant
2. Virtual Fuel Cell Power Plant (Vaillant) (PDF; 2.2 MB)
3. KonWerl energy park (PDF; 210 kB) in the KonWerl 2010 project
4. The regenerative power plant in Bremen
5. The Harz regenerative model region - RegModHarz

Footnotes

1. ↑ BMWi: What actually is a "virtual power plant"? Retrieved August 27, 2016 . 
2. ↑ Available control reserve from small CHP systems
3. ↑ http://www.dispower.org
4. ↑ http://www.fenix-project.org
5. ↑ Archived copy ( Memento of the original from July 16, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
6. ↑ Archived copy ( Memento of the original dated December 13, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
7. ↑ Archived copy ( memento of the original from July 5, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
8. ↑ Germany's largest "power plant". Retrieved August 27, 2016 . 
9. ↑ Virtual Power Plant. Retrieved August 27, 2016 . 
10. ↑ Virtual Power Plant. (No longer available online.) Archived from the original on August 27, 2016 ; accessed on August 27, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
11. ↑ Technology: The Virtual Power Plant Next Pool. Retrieved August 27, 2016 . 
12. ↑ E.ON: Virtual Power Plants. E.ON, accessed November 29, 2019 . 
13. ↑ KEMWEB GbR Mainz: in.power GmbH | in.power energy network & trade. Retrieved November 29, 2019 . 
14. ↑ Prequalification for the provision of SRL / implementation of the SRL pool model. Retrieved August 27, 2016 . 
15. ↑ Energy transition with the help of Demand Response Management. Retrieved August 27, 2016 . 
16. ↑ Switchable loads. Retrieved August 27, 2016 . 
17. ↑ Incorporation of generating plants into balancing energy pools. Retrieved August 27, 2016 . 
18. ↑ Balancing energy marketed optimally. Retrieved August 27, 2016 . 
19. ↑ Control Energy Pool News. (No longer available online.) Archived from the original on August 27, 2016 ; accessed on August 27, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
20. ↑ Biogas plant: direct marketing & control energy. In: www.next-kraftwerke.de. Retrieved January 6, 2017 . 
21. ↑ Technology Review: The company connects small electricity providers to create a virtual power plant. In: Technology Review. Retrieved January 6, 2017 . 
22. ↑ Control energy pool. Retrieved August 27, 2016 . 
23. ↑ Control energy pool. Retrieved August 27, 2016 . 
24. ↑ Official project website of Combined Power Plant 2
25. ↑ Final report
26. ↑ BEE press release
27. ↑ Press release of the Renewable Energy Agency ( Memento of the original from April 7, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.