Energy market

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The energy market describes the market for grid-based energy supply by energy supply companies with electrical energy and natural gas , in which as many parts of the supply chain as possible are subject to free competition .


By means of competition, consumers should be supplied in line with the market at the cheapest market prices . A change of electricity provider or gas provider is possible at any time provided the notice periods are observed . The supply networks required for supply cannot reasonably be subjected to competition. The respective network operator has a monopoly here . So that the network operator does not exploit its monopoly position in its favor, the fees for the use of the networks ( network usage fees ) are regulated by the federal network agency .

Characteristic features on the energy market are on the supply side, the cable connection to existing supply networks , the insufficient storage capacity and the high capital intensity . The offer on the energy market is characterized by the very limited storage capacity possible, so that delivery bottlenecks can arise quickly. The storage capacity is limited to strategic oil reserves and gas reserves . Electrical energy can only be stored to a limited extent and must also be consumed at the time of generation. Weather- related disruptions in the generation area (such as calm in wind energy ) or on supply lines (such as the breakdown of high-voltage lines in a storm or snow ) usually lead to immediate delivery bottlenecks. The demand for energy is subject to seasonal fluctuations , on which the inelastic supply is oriented by adjusting the base , medium and peak loads .

Electricity trading in Europe

Electricity trading volume in European countries in 2008 in TWh
country import export Trade balance
Belgium 17.036 6.561 −10.475
Bulgaria 3,096 8.440 5.344
Denmark 8.545 10.772 2.227
Germany 40.245 62.695 22.450
France 10.176 56.495 46.319
Greece 7.575 1.964 −5.611
Great Britain 12,448 0.923 −11.525
Italy 43.284 3.394 −39.890
Croatia 12.247 5.669 −6.578
Luxembourg 6.819 2,464 −4.355
Netherlands 25.023 9.282 −15.741
Norway 0.756 7.970 7.214
Austria 22.033 16,528 −5.505
Poland 9.021 9,704 0.683
Portugal 10,597 1,315 −9.282
Romania 2.609 7,042 4,433
Sweden 1,885 6,937 5.052
Switzerland 30.494 30.525 0.031
Serbia 9.136 8,574 −0.562
Slovakia 9.414 8,889 −0.525
Slovenia 6.233 7.827 1,594
Spain 5,894 16,485 10,591
Czech Republic 8.524 19.986 11,462
Hungary 12.772 8,867 −3.905

The trading of electricity has a long tradition in Europe; it developed hand in hand with the progress in the use of electrical energy. When the markets were still monopoly, trading in electricity between around 50 to 60 suppliers primarily served the purpose of secure self-sufficiency in their areas. The predominantly local and national orientation can still be seen today: the European electricity network acts like a single organism, but in reality consists of eight different regions, whose physical bottlenecks at the borders are a uniform electricity network (“European copper plate”) and a transnational liberalization of the electricity market hinder.

Electricity is sold on exchanges, e.g. B. the European Energy Exchange (EEX), as well as bilaterally traded ( OTC trading ). A distinction can be made between short-term trading (intra-day, day-ahead, after-day) and long-term trading (futures, forwards). Short-term trading is mainly characterized by the fact that electricity is not a storable “good”, but rather that production and consumption must take place at the same time.

In 2008, electricity production within the UCTE network was 2642 TWh, of which 285 TWh were traded across borders within this network. An additional 50 TWh were exchanged with external networks.

Situation in Germany


The electricity and power market in Germany is characterized by a number of market distortions. Before the liberalization of the electricity sector, the majority of the existing power plant output was generated outside of market conditions and without any major investment risk, the external costs of electricity generation are only internalized to a small extent and the market is dominated by a few groups. Therefore, the electricity market is not a homogeneous market that corresponds to the economic textbook , but a "highly complex sector with many sub-markets and individual segments that are expressly excluded from competition". In contrast, the prices for the actual energy supply are subject to competition. In Germany, the prices for using the networks are subject to regulation by the competent regulatory authority, the Federal Network Agency . The liberalization of the energy markets does not include the supply of district heating . It is only operated with local networks. The heat prices must meet the requirements of Section 24 AVBFernwärmeV and take appropriate account of the respective conditions on the heating market.

Critics complain that competition on the German energy market is not functioning properly. Around 80 percent of the electricity supply and a large part of the trade are controlled by four producers (E.On, RWE, EnBW and Vattenfall). Around three quarters of electricity trading takes place outside the energy exchange and is not subject to any supervision. The energy market is one of the most opaque markets. Errors in the system would endanger the security of supply. The chairman of the Monopolies Commission , Justus Haucap, also criticizes the non-functioning competition in energy generation in Germany. The former energy expert of the Federal Association of Consumer Organizations, Holger Krawinkel , criticized that the four dominant energy companies had more market power than before liberalization. This is mainly due to the failure of the policy , which has not ensured sufficient competition.

Development of the electricity trade balance

German electricity trade balance in TWh
year Electricity import Electricity export Electricity trading balance
1990 31.9 31.1 -0.8
1991 30.4 31.0 0.6
1995 39.7 34.9 -4.8
2000 45.1 42.1 -3.1
2001 43.5 44.8 1.3
2002 46.2 45.5 -0.7
2003 45.8 53.8 8.1
2004 44.2 51.5 7.3
2005 53.4 61.9 8.5
2006 46.1 65.9 19.8
2007 44.3 63.4 19.1
2008 40.2 62.7 22.4
2009 40.6 54.9 14.3
2010 42.2 59.9 17.7
2011 49.7 56.0 6.3
2012 44.2 67.3 23.1
2013 38.4 72.2 32.3
2014 38.9 74.5 35.6
2015 33.0 83.1 50.1

While the German electricity trade balance was relatively balanced in the 1990s, the amount of electricity exported by Germany has increased since 2003, while the amount of electricity imported has remained roughly the same. Since then, the German electricity trade balance has shown a considerable export surplus. In 2013, gross electricity imports reached their lowest level since 1998, while both gross electricity exports and net electricity exports reached record levels in 2014. In 2015, the net electricity export rose again significantly to around 50 TWh . The reasons for this are large overcapacities in the conventional power plant sector, v. a. for coal-fired power plants that are available for export. The production of electricity from coal remained practically unchanged compared to the previous year , despite the significant increase in production from renewable energies by around 30 TWh . During 8074 of the 8760 hours of the year (92% of the time), more electricity was exported to neighboring countries than was imported. The annual average output of these exports was 5.7 GW and thus corresponds roughly to the nominal output of 4 nuclear power plant blocks.

In 2014, according to data from destatis , Germany exported the record value of 34.1 TWh of electrical energy on balance. In 2012, electricity exports earned 3.7 billion euros, while imports had to spend 2.3 billion euros, so that Germany was able to achieve an export surplus of 1.4 billion euros. The value of the exported electrical energy was 5.56 ct / kWh, while the value of the imported electrical energy was slightly lower at 5.25 ct / kWh. The reason for this is that France exports a lot of electrical energy at low prices during times of low electricity demand in order to keep its v. a. Not having to throttle from existing nuclear power plants operating at the base load . Germany, on the other hand, exports v. a. at times of higher electricity demand, i.e. during medium and peak loads , when electricity prices are usually higher.

In 2013, a record electricity export of around 32.3 TWh was achieved. The cause was v. a. the strong production of conventional power plants, v. a. of coal power plants. In total, electrical energy to the value of 3.76 billion euros was exported, the balance after deducting the costs of imported electricity was 1.95 billion euros. As in previous years, the price for exported electricity was on average 5.2 ct / kWh, above the price for imported electricity (4.9 ct / kWh). The same applies again to 2014, albeit at a lower level.

Import and export quantities

German electricity trading in millions of kilowatt hours from January to November 2010
country import export Trade balance
Denmark 2,478 13,089 +10,611
France 14,517 665 −13,852
Luxembourg 8,302 545 −7,757
Netherlands 5,957 13,238 +7,281
Austria 3,002 7,392 +4,390
Poland 118 5,022 +4,904
Sweden 1.002 2.123 +1,121
Switzerland 2,645 5,765 +3,120
Czech Republic 1,175 5,534 +4,359
total 39,196 53,373 +12,177

Integration of fluctuating electricity generation

Economic difficulties of existing and newly planned conventional power plants in view of falling prices on the electricity wholesale market have triggered a discussion about the future design of the electricity market, since power plants can no longer be operated constantly due to the fluctuating quantities of renewable energies (photovoltaics, wind). This question concerns not only conventional, but also systems based on renewable energies, such as biogas systems. Controllable renewable energies such as B. Geothermal power plants , hydropower plants and biomass power plants and conventional power plants must therefore be able to adapt to the fluctuating supply of wind and sun in order to guarantee security of supply. In addition, the expansion of the electricity grid, the adaptation of electricity demand to electricity generation, e.g. B. through intelligent power consumption and smart grids as well as the construction of energy storage systems are becoming increasingly important. According to the assessment of the "Leitstudie Stromarkt" on behalf of the Federal Ministry for Economic Affairs and Energy (2015), the introduction of capacity markets is currently not necessary to ensure the functionality of the electricity market and security of supply. First of all, it is important to tap the optimization potential in the existing electricity market design.

Overview of legal regulations for the electricity and gas markets



European Union

Liberalization of the energy markets

Theoretical background

Originally, electricity and gas supplies were seen as natural monopolies that are justified in a market economy. In contrast, the basis for the liberalization of the energy markets is provided by the essential facility theory . It states that natural monopolies are only limited to that part of the value chain for which competition, taking economic costs into account, does not make sense. The provider has a unique position for these "essential facilities". These “essential facilities” are, for example, the local distribution networks and the national transmission networks for electricity and natural gas. A parallel construction for these networks does not generally make economic sense.

On the other hand, unlike distribution, generation does not require a monopoly, which is why some states have pushed ahead with deregulating the electricity markets. In theory, this deregulation results in a number of advantages: These include higher economic efficiency in the energy sector, lower electricity prices and the stimulation of private investments in new power plants and electricity networks. In practice, however, deregulation created new problems (see below), which is why its usefulness is discussed controversially in retrospect.

The power of disposal over the "essential facilities" should not lead to a dominant position on the upstream and downstream markets. The essential facilities are therefore to be made available to third parties for shared use in return for appropriate remuneration, which may be determined by a regulator.

The “essential facility” theory is anchored both in Article 102 of the TFEU Treaty and in Section 19 IV of the Act against Restraints of Competition (GWB).

Steps towards a fully liberalized energy market

  • Third party network access to transmission and distribution networks
  • Regulation of network usage charges and network connection conditions
  • Unbundling of network operators ( unbundling ) in order to enable non-discriminatory competition for third parties (equality of arms).

History of the liberalization of the energy markets

  • 1996 First EU directive on electricity market liberalization:
  • 1998 First EU directive on gas market liberalization
  • 1998 Liberalization of the German electricity market. The EU directive on the internal electricity market is implemented in national law with the amended Energy Industry Act of 1998.
  • 2003: Revision of the EU directives for the liberalization of the energy markets
  • from 2004 liberalization of the German gas market
  • July 7, 2005: The amended Energy Industry Act implements the European directives on the internal electricity and gas market from 2003 into national law.
  • 2009: renewed revision of internal market regulations by the EU ( third EU energy package )

Implementation and problems

The efficiency gains and economic advantages hoped for through competition have so far only been achieved very rarely. In most markets, liberalization made energy more expensive, especially for small consumers. This is particularly the case where liberalization was accompanied by privatization. The reason for this is that liberalization in a functioning market does not lead to lower, but only to competitive prices. In many electricity market liberalizations, the competition between the individual producers is a particular problem that has only been partially resolved so far. From a business point of view, competitive prices require an appropriate return on the capital employed. B. in Switzerland is determined by ElCom . The capital employed in the networks was tw. synthetically valued , which caused considerable appreciation gains, which ultimately resulted in higher costs being passed on to consumption via the energy price.

Last but not least, there are several obstacles to overcome in the transition to a liberalized market. A too rapid transition to stranded investments can result in power plants that are no longer profitable. In addition, the lack of internalization of external costs , e.g. Problems caused by pollution, carbon dioxide emissions or the risks of nuclear energy. If, as is the aim of liberalization, the market is to find the most economically efficient mode of production, then it is imperative that all factors that distort competition are avoided and that the cost truth be established by internalizing all external factors. If this does not happen, the efficiency advantages of a liberalized market can be negated by negative effects on the environment. Options for producing this true cost are incentive taxes such as B. a CO2 tax or a functioning emissions trading system . These necessary mechanisms set limits to a completely free energy market. So far (April 2014) these external effects have only been internalized to a small extent; full internalization is not foreseeable. So z. For example, the "Annual Report on Energy Consumption in Germany in 2013" by the AG Energiebilanzen concludes that "the incentives intended with emissions trading for emission-reducing behavior at such certificate prices [of approx. 5 euros / ton] are not to be expected".

In addition, the deregulation of the electricity supply in some countries led to a decline in security of supply . While a very robust power supply system with corresponding reserves was built up before liberalization, in the case of privately operated infrastructure it can be expected that necessary investments will be avoided or postponed. The main goal of private companies is to make short-term profits, so they have little interest in long-term investments that will take many years to become profitable. Overarching economic or social goals also hardly play a role in their actions. According to Schwab, this "leads to compromises in terms of security, reliability and availability [...], accompanied by significant, hidden economic damage." In order to at least mitigate these consequences, various measures in the technical area as well as training are necessary.

Since in a liberalized electricity market the electricity supply contracts come about independently of the electricity network operators due to the free choice of suppliers, but the traded electricity must be distributed by them on the existing network, the requirements for the transport network management have increased. The greater load on individual lines associated with this electricity trade, combined with the reduced safety distances to the stability limits, have led to network breakdowns becoming more frequent with liberalization. The number of critical network states also increased due to violation of the n-1 criterion . Particularly serious problems arose in North America, especially the USA. As a result of deregulation, electricity trading in the deregulated areas increased by 400% between 1999 and 2002. This led to a sharp increase in economically motivated power transports, whereupon the overload of the power grid increased 300% and there were a number of large-scale power outages . However, critical grid situations can also arise regardless of the unplanned drop in wind power feed-in.

In addition, badly implemented deregulations increase the risk of market manipulation, such as B. happened during the energy crisis in California 2000/2001 . There was a power shortage there due to higher electricity demand, which was artificially exacerbated by various energy companies, in particular Enron . From 2001 onwards, despite high demand, these companies deliberately switched off various power plants in order to artificially drive up electricity prices further and to further increase their revenues. This ultimately led to a major blackout that left 1.5 million people without access to electricity on March 19-20, 2001.


Competition in the electricity market

Competition in the electricity market takes place in the segments of generation, trading and sales, while the value-added stages of transport and distribution are regulated as natural monopolies. The state-regulated transmission and distribution network charges make up around a quarter of electricity prices .

In a supply contract, the supplier undertakes to feed exactly as much electricity into the network as the consumer uses. In the case of large consumers, the consumption is continuously determined; in the case of small consumers, the consumption (level and chronological sequence) is estimated and then exactly balanced after the next reading. This ensures that in the medium term at least as much energy is fed into the grid as the customer consumes. Since every current fed in is three-phase alternating current according to VDE / UCTE standards, the energy can no longer be differentiated or separated after being fed into the grid. So it is not possible to say “which electricity” will reach a customer. Anyone who has ordered green electricity is supplied with the same electricity and often from the same cable as any other electricity customer; nevertheless, the amount of electricity it consumes is produced according to the agreed (slightly different depending on the provider) conditions.

Depending on the size of the customer, competition in the electricity market is very different.

In the area of ​​major customers, industrial customers and municipalities, there is intense competition in the electricity market. The decision for an energy supplier is made in the public sector in the form of public tenders , which are published in the official gazettes. In the area of ​​major customers, the award is made on the basis of comparisons of offers or auctions on the Internet. (See also VIK and VEA )

There is limited competition in the area of ​​small consumers. The electricity providers usually offer standardized electricity supply contracts on the Internet. Due to the increasing price differences to the offers of the respective associated sales of the local network operator, the switching rate (at a low level) is also increasing. According to the Federal Network Agency's 2009 monitoring report, it is 5.3% per year for household and small business customers, while it is between 10.5 and 12.5% ​​for large customers. In order to improve the negotiating position and thus also the prices of small business customers, they often come together to form regional energy purchasing groups.

80 percent of German electricity is produced by four corporations . Competition suffers as a result: while the profits of the energy companies have multiplied in recent years, consumer prices for electricity have risen by over 50 percent since 2000 (as of 2007). It should be noted that since 2000 the electricity tax has also risen from around 1 to 2 cents per kWh. Measured by the number of household customers, the market share of the four large energy groups is falling. While they supplied 50.1% of household customers with electricity in 2008, in 2010 it was 43.8%.

Competition in the gas market

Investigation of the gas prices of various providers by the German Federal Cartel Office

Competition in the gas market has so far been little developed and is concentrated on a few large consumers . In this area, however, there is particularly fierce competition with other energy sources such as light heating oil , since many large consumers use both gas and heating oil.

On October 1, 2006, private customers in Germany should for the first time be given the opportunity to freely choose their gas supplier. With a few small exceptions, there are only a few regionally operating alternative gas providers. It was expected that this situation would change little in the 2006/2007 gas year .

The causes were:

  1. In order to implement the legal requirements, a gas network access model was developed by the gas industry with the assistance of the Federal Network Agency. To implement this, the agreement on cooperation pursuant to Section 20 (1) b) EnWG was signed for the first time on July 19, 2006 between the operators of gas supply networks in Germany . The main controversial issue is that the Gas Cooperation Agreement (KoV) allows or requires the single booking variant (EBV) in addition to the two-contract variant (2VV). While the two-contract variant implements an entry-exit model across several networks within a market area, the single booking model offers the energy supplier the option of continuing to conclude contracts individually with each network operator at his request. Critics see a possible potential for abuse and inefficiencies here.
  2. The German gas supply network has meanwhile been divided into 18 market areas. Energy suppliers can use gas quantities flexibly in a market area. It is controversial whether this flexibility is not also possible in larger areas, i.e. whether the market areas could be reduced. In the meantime [as of October 2011] there are only two market areas (Gaspool and NetConnect Germany), as the various providers have joined forces in cooperation.
  3. The supply of private customers requires processes suitable for mass business between the network operators and the gas suppliers with appropriate IT support. These are still in development.
  4. For the use of the networks, network fees are to be paid by the energy suppliers. These are currently still being examined by the regulatory authorities, and only a few approval procedures have been completed. Therefore, new energy providers do not yet have a reliable calculation basis for their offers.

The Federal Network Agency is currently checking points 1 and 2 for abusive behavior on the part of the network operator (Ref .: BK7-06-074) and has initiated a process of establishing a change of supplier for gas (Ref .: BK7-06-067) in order to implement a change of supplier suitable for mass business.

See also


  • Annika Krisp: The German electricity market in Europe. Between competition and climate protection . Dissertation, University of Giessen 2007 ( full text )
  • PricewaterhouseCoopers AG (Ed.): Unbundling and regulation in the German energy industry. Practical manual for the Energy Industry Act. Haufe, Planegg u. a. 2007, ISBN 978-3-448-08025-4 .
  • Adolf J. Schwab: electrical energy systems. Generation, transport, transmission and distribution of electrical energy . Springer Verlag, Berlin a. a. 2006, ISBN 3-540-29664-6 .
  • Anton Bucher, Niklaus Mäder: The long way to the market - From the first considerations to the revision of the Electricity Supply Act , Bulletin SEV / VSE , 9/2010, p. 35 ff. PDF
  • Peter Becker: Rise and Crisis of German Electricity Companies - At the same time a contribution to the development of energy law , Ponte Press, 2nd edition, Bochum 2011, ISBN 978-3-920328-57-7
  • Christiane Nill-Theobald, Christian Theobald: Grundzüge des Energiewirtschaftsrechts , CH Beck-Verlag, 2nd edition, Munich 2008, ISBN 978-3-406-65123-6 .
  • Annually published: Hans-Wilhelm Schiffer: Energiemarkt Deutschland. Yearbook 2015 , TUV Media, Cologne 2014.

Web links

Individual evidence

  1. Philipp Büsch, The idea of ​​competition in energy law , 2014, p. 71
  2. Urs Dolinski / Hans-Joachim Ziesing, The energy market in Bavaria until 1990 , 1974, p. 166
  3. positive trade balance = export surplus; negative trade balance = import surplus; Source: european network of transmission system operators for electricity ( Memento of the original dated December 11, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  4. Valentin Crastan , Electrical Energy Supply 1 , Berlin - Heidelberg 2012, p. 10f.
  5. U. Leprich , U. Klann, A. Weber, A. Zipp, Marketing of FEE systems in the existing electricity sub-markets - a sensible goal? IZES, October 7, 2013, accessed on July 2, 2014, online ( memento of July 14, 2014 in the Internet Archive ).
  6. Martin Gerth: Errors in the system . In: Wirtschaftswoche , No. 9, February 27, 2012, p. 84 f.
  7. Electricity oligopoly rakes in money .
  8., October 20, 2010: [1]
  9. a b Evaluation tables for the German energy balance. (PDF) Arbeitsgemeinschaft Energiebilanzen eV, August 31, 2015, accessed on December 22, 2015 .
  10. a b c AG Energiebilanzen: "Gross electricity generation in Germany from 1990 according to energy sources". As of December 11, 2015.
  11. Climate protection: Hendricks criticizes the massive increase in electricity exports . In: Spiegel-Online , December 28, 2015. Accessed December 28, 2015.
  12. Bruno Burger German electricity exports achieved a record total of over 2 billion euros . Fraunhofer ISE website. Retrieved February 24, 2016.
  13. Germany also exported more electricity than it imported in 2012 . destatis. Retrieved April 2, 2013.
  14. German power exports more valuable than imports
  15. Germany 2013 with record profit in electricity exports ( Memento from July 25, 2014 in the Internet Archive ). In: Stern , July 17, 2014. Retrieved July 17, 2014.
  16. German electricity exports still more valuable than imports ( Memento from June 20, 2015 in the Internet Archive ). In: Renewables International , April 21, 2015. Retrieved April 22, 2015.
  17. Arbeitsgemeinschaft Energiebilanzen: Energy consumption in Germany data for the 1st-4th Quarter 2010. Chapter 7.2 ( Memento of the original from August 8, 2014 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. @1@ 2Template: Webachiv / IABot /
  18. Lead study electricity market. Work package optimization of the electricity market design . BMWI website. Retrieved April 22, 2015.
  19. a b c d e Nicola Armaroli , Vincenzo Balzani , Towards an electricity-powered world . In: Energy and Environmental Science 4, (2011), 3193-3222, p. 3202f doi : 10.1039 / c1ee01249e .
  20. Directive 96/92 / EC (PDF) - Common rules for the internal market in electricity
  21. European Union (June 22, 1998): Directive 98/30 / EC - Common rules for the internal market in natural gas (PDF)
  22. European Union (1998): EU directive on the internal electricity market for the amended Energy Industry Act of 1998
  23. European Union (June 26, 2003): Directive 2003/54 / EC - Common rules for the internal market in electricity (PDF)
  24. Directive 2003/55 / ​​EC of June 26, 2003 on common rules for the internal market in natural gas (PDF)
  25. ^ Text of the Energy Industry Act
  26. Valentin Crastan : Electrical energy supply 2. Berlin, Heidelberg 2012, p. 85.
  27. Valentin Crastan: Electrical energy supply 2. Berlin, Heidelberg 2012, p. 86.
  28. Federal Office of Energy SFOE - press release: New measures against high electricity prices: Federal Council revises ordinance
  29. Valentin Crastan, Electrical Energy Supply 2 , Berlin - Heidelberg 2012, p. 87.
  30. Valentin Crastan, Electrical Energy Supply 2 , Berlin - Heidelberg 2012, p. 88.
  31. ^ AG Energiebilanzen , Energy consumption in Germany in 2013 , p. 41.
  32. a b Adolf J. Schwab , electrical energy systems. Generation, transport, transmission and distribution of electrical energy , Berlin Heidelberg 2012, p. 8.
  33. See Adolf J. Schwab, Elektroenergiesysteme. Generation, transport, transmission and distribution of electrical energy , Berlin Heidelberg 2012, p. 761.
  34. ^ Adolf J. Schwab, electrical energy systems. Generation, transport, transmission and distribution of electrical energy , Berlin Heidelberg 2012, p. 901.
  35. ^ Adolf J. Schwab, electrical energy systems. Generation, transport, transmission and distribution of electrical energy , Berlin Heidelberg 2012, p. 902.
  36. Sharp sword against Eon and Co., TARIK AHMIA, daily newspaper of November 12, 2007
  37. Federal Network Agency - Monitoring Benchmark Report 2011 . P. 47
  38. Agreement on cooperation in accordance with Section 20 (1) b) EnWG between the operators of gas supply networks in Germany