What would cause a power failure in a split second?

Power failure

Under a Power failure (also in Englishblackout) is understood to mean an unintentional interruption of the supply of electricity.

Duration of power outages (SAIDI value) in an international comparison (as of 2014)


Major power failure scenario

Power supply companies usually cite a defect in a power plant, damage to a line, a short circuit or a local overload of the power grid as reasons for a power failure in an entire area. However, these occasions would generally not be a reason for a power outage if the regulation was functioning. Supraregional power grids are operated according to the (n − 1) criterion. This means that electrical equipment, a transformer, a line or a power plant can fail at any time without overloading other equipment or even interrupting the energy supply. The integrated networks in Germany and in the UCTE area must be managed according to this standard. Does it come, however - z. B. due to a defect in a power plant - if several transformers or lines fail at the same time, the power supply can be interrupted. In a correctly operated system, at least two events must come together so that an interruption in supply can occur.

The (n-1) criterion valid in transmission network operation was originally developed for systems with local network coverage and short transport distances. This criterion proves to be inadequate against large-scale and supra-regional network failures (blackouts), the frequency and extent of which are increasing worldwide.[12] In the decades between 1965 and 1995, large-scale network failures still occurred sporadically; after 2005 there were an average of 14 events per year.[13] They have their reasons in multiple failures and / or cascading errors in the network and are among other things. attributed to the high utilization of the transmission network (which leads to restrictions in network renewals, network reinforcements and expansions), the inconsistent feed-in from renewable energy sources and the vulnerability of large transmission routes from the producer to the consumer. The shutdown of the 7 + 1 nuclear power plants in March 2011 exacerbated this situation due to the loss of power in southern Germany.

The investigations into the causes of the blackouts that have occurred around the world show that the main cause complexes are: privatization and liberalization led to the neglect of the networks and their infrastructures; the increased growth of renewable energy causes the instability of the grid.[14]


If there is not enough energy to be activated for the current demand in your own network, e.g. B. If the network control fails, the network frequency falls in particular, because the load difference is initially covered by the kinetic energy of all rotating masses in the generators. This case is referred to as underfrequency and is divided into five levels in the Western European network (UCTE control area): In addition to the short-term activation of reserves, in particular automatic load shedding is carried out.

If stabilization cannot be achieved as a result, the last consequence is a separation into several, mutually asynchronous network areas, between which there is no longer any power flow. This leads to total failures in individual network areas, as the power plants are automatically disconnected from the network. Larger caloric power plants (base load power plants) such as coal-fired power plants or nuclear power plants try to cope with their own needs when the grid is disconnected by reducing the output and to maintain this non-optimal operating state for several hours. If this catching and holding in the power plant's own consumption does not succeed, the affected power plant units are switched off, which leads to a longer process of recommissioning.


The network connections are switched to different locally separated substations so that if one substation fails, the other can continue to be supplied with power. The higher-level network is usually the same for both substations, so that a fault there also affects both connections. Much more important is z. B. the use of an uninterruptible power supply (UPS) system in hospitals.

In the IT area, power failures can result in the loss of unsecured data and, in individual cases, damage to devices. In the event of a power failure, individual devices can still send messages to other devices, e.g. B. a dying gasp signal.

Serious economic damage can also occur in industrial companies that are dependent on a continuous supply of energy and cannot easily continue a production process after a service interruption (e.g. the chemical industry, food processing, etc.).

Even in the private sector, longer power failures can have unpleasant consequences:[15]

  • Lighting: Electric lights, traffic lights, signals
  • News: Mains voltage radio and television sets; Batteries run out quickly. Many transmission systems have emergency power generators.
  • Communication: Mobile telephony is only available for a limited time in the event of a longer power outage, as cell phone masts usually only bridge a few hours with the help of batteries; Fixed line and internet are i. A. depending on (currentless) end customer routers.
  • Security: Door intercom systems and door openers, access security systems, alarm systems, fire alarms and warning lights for air traffic on tall structures only work if and as long as batteries or emergency power systems supply as a replacement. Hospitals in this country have emergency power generators and particularly critical areas such as the operating theater and intensive care medicine have an uninterruptible power supply. Escape route marker lights in larger (residential) buildings are usually individually battery-powered and light up for a while.
  • Mobility: Elevators, cable cars, parking garage gates; Some railways have their own power supply networks.
  • Water: Drinking water treatment and sewage disposal with pumps fail after a while. In the case of water supply networks that are operated by the natural gradient and without pumps (such as the Viennese water supply via the high spring water pipes), a power failure has only a minor effect on the supply.
  • Fuel: Petrol stations usually do not have an emergency generator or connection for it; the dispenser pumps fail.
  • Warmth: Air conditioning, ventilation, electric heating; But even oil, gas and pellet central heating systems have no control, no ignition spark and no circulation pump without electricity.
  • Money: Bank ATMs are mostly inoperative.
  • Shop: Supermarkets close, as tills and main lighting often fail, as do restaurants. Electric sliding and revolving doors are inoperable.
  • Food: Fridge and freezer contents can thaw / spoil in the event of a prolonged power failure.

A study by the Office for Technology Assessment at the German Bundestag (TAB) comes to the conclusion that a long-term, large-scale power failure would affect all critical infrastructures and a collapse of the entire society could hardly be prevented. Despite this potential for danger and catastrophe, social risk awareness in this regard is only rudimentary.[16]

Emergency power operation

Power failures are particularly critical for hospitals, as they need power to operate medical devices. But also safety-relevant systems (such as radar devices for air traffic control, traffic lights or signal systems for railways) or other suppliers (such as waterworks, gasworks or telecommunications companies) require electricity to work. For this reason, hospitals and other critical facilities, like many companies, have emergency power generators that are often operated with diesel generators and switch on automatically as soon as a power failure occurs (general backup power supply). In addition, many facilities have several network connections to (largely) independent networks.

The period of time that can be bridged in emergency power operation differs greatly. Public service broadcasting should remain broadcastable for at least 3 days to inform the population - for example, broadcasting Berlin-Brandenburg has 8 days, but on only one radio wave instead of the six frequencies in normal operation.[17]


The central telecommunication facilities and main exchanges are consistently prepared for longer emergency power operation. The local exchanges, which can supply the end devices with electricity with copper cables, are usually only designed with buffer batteries for 4 hours. In the event of a long-term failure, only a few terminals and in particular public telephone booths will continue to be operated there. The cellular networks work with emergency batteries in the event of a power failure. In this way, continued operation for about a day can be ensured, but only on a greatly reduced number of channels. A battery backup of at least 12 hours is provided for the BOS radio,[18] which ensures the full operation of all end devices; thereafter, there may also be a restriction in the employability.

Economic costs

A large part of the consequences includes that parts of the added value in the affected economy are lost for a certain period of time. Economics Minister Philipp Rösler said in May 2011: “In studies, the amount of damage caused by a blackout is at least 6.50 euros per kilowatt hour. We use around 1.6 billion kilowatt hours a day. The daily gross domestic product in Germany is around 6 billion euros. If the power went out for a day in all of Germany and nothing could be produced anymore, that would be considerable damage. In addition, there would be indirect costs. "[19]

A study by the Technical University of Berlin from 2011 estimates these economic costs at a weighted average of at least EUR 8.50 / kWh. The costs of the individual consumer groups are estimated at at least the following values:[20]

AgricultureIndustryServicesPublic administrationhouseholds
2.34 EUR / kWh2.49 EUR / kWh16.35 EUR / kWh5.53 EUR / kWh15.70 EUR / kWh

Strictly speaking, all the figures are hypothetical, since the actual damage, apart from the non-availability of services, can hardly be estimated. The Hamburg World Economic Institute (HWWI) came to the conclusion in 2013:

  • There is a growing potential for risk.
  • The study is deliberately limited to power outages of no more than one hour.
  • Costs that are difficult to estimate in the event of longer failures, such as the interruption of the supply chain or the failure of cooling systems, are thus excluded from the analysis.[21]

The blackout simulator comes from an Austrian and subsequently European research project,[22] with which a cost simulation (unavailability of services) can be carried out. However, no damage resulting from a blackout can be taken into account here.

Power failure in nuclear power plants ("blackfall")

To protect against external network failures, the nuclear power plants (KKW) in Germany must comply with the nuclear rule "KTA 3701"[23] have at least two network-side supply options and - in the event of failure of the external networks - automatic switchover to the power plant's own demand (load shedding to internal demand). Only if these three feed paths fail does the emergency power case occur, which is safeguarded by the redundant emergency power system of the power plant, which covers the power requirement for the redundant after-cooling pumps for residual heat removal. The emergency power case is an explicit investigation case in the “Probabilistic Safety Analyzes (PSA)” of the NPP (“triggering accident”) and is discussed in[24] given with an occurrence frequency of H = 2.5% per year.

In various cases, however, NPPs have already struggled with problems relating to the proper functioning of these emergency power generators or their connection devices. The best known in this regard are probably the Fukushima nuclear accidents and the 2006 incidents at the Forsmark nuclear power plant in Sweden. Similar incidents occurred in 1975 at the Greifswald nuclear power plant, in 1982 in the Belgian nuclear power plant in Doel, in 1999 in the French nuclear power plant in Blayais, in 2000 in the New York nuclear power plant in Indian Point 2, in 2001 in the Taiwanese nuclear power plant in Maanshan, in 2004 in the nuclear power plant in Biblis, in 2007 in the French nuclear power plant in Dampierre and in the Penly nuclear power plant Swiss nuclear power plant Beznau 1 and 2011 in the French nuclear power plant Tricastin.

On April 26, 1986, the operating personnel of the Chernobyl nuclear power plant practiced the control of a nuclear reactor (Block 4) in the event of a complete power failure. Serious violations of the applicable safety regulations and the design-related properties of the graphite-moderated nuclear reactor led to an uncontrolled increase in output, which led to the reactor fire and explosion (Chernobyl disaster).

Reliability of the power supply in the Federal Republic of Germany

Downtime in different countries

In its availability statistics for 2014, the Federal Network Agency (BNetzA) determined that the unavailability of electrical energy was 12 minutes and 28 seconds, which was the lowest value since the systematic measurements began. In 2013 the value was over 15 minutes, in 2008 it was 16.89 minutes[25]

In 2006 it was over 20 minutes. Although it is often feared, the energy transition and the decentralized feed-in of renewable energies will continue to have no negative effects on the security of supply for end consumers.[26][27] With an average unavailability of electricity of 15.91 minutes for end consumers, Germany was the country with the highest security of supply in 2012.[28]

Power failures in the traction current network and in the public network almost never have reciprocal effects because both systems are operated largely independently of one another, partly because of different network frequencies. With the SAIDI (System Average Interruption Duration Index) an internationally recognized statement about the quality of the power grid can be made.

SAIDI values ​​for Germany 2006–2012

The reliability of the interconnected network is determined today - as experience from past network failure events show - by the risk of multiple errors (cascading errors) in the network. The system index (SAIDI) does not provide any information on this.[12][13][14]

General dataLow voltageMedium voltageSAIDI
Reporting yearNumber of network operators / networksEnd consumers (in millions)Number of interruptions (in total in thousands)SAIDI (minutes)Number of interruptions (in total in thousands)SAIDI (minutes)SAIDI (minutes)Unavailability in%
2018866/87250,7143,72,3423,711,5713,910,0026 %
2017862/86950,5143,02,2223,512,9215,140,0029 %
2016860/86850,3148,32,1024,310,7012,800,0024 %
2015850/86049,9150,92,2526,710,4512,700,0024 %
2014874/88449,6147,82,1926,010,0912,280,0023 %
2013868/87849,5151,42,4727,812,8515,320,0029 %
2012866/88349,3159,02,5732,013,3515,910,0030 %
2011864/92848,9172,02,6334,712,6815,310,0029 %
2010890/96349,0169,22,8037,112,1014,900,0028 %
2009821/84248,4163,92,6335,112,0014,630,0028 %
2008813/83448,4171,52,5736,614,3216,890,0032 %
200782548,5196,32,7539,516,5019,250,0037 %
200678148,5193,62,8634,418,6721,530,0041 %

Data: Federal Network Agency[29]

Reliability of the power supply in a European comparison

Power failure in the media

The novel Blackout - Tomorrow is too late by Marc Elsberg describes the effects of a large-scale power failure in Europe over two weeks; it is based on the 2011 study by the Technology Assessment Office.

See also

Web links


Individual evidence

  1. ↑ The risk of power failure increases - causes for a power failure
  2. Individual failure data of the reported supply interruptions in 2018. (xlsx, 10 MB) Federal Network Agency, accessed on October 23, 2019.
  3. Reliability of supply - the FNN fault statistics. VDE, accessed on October 22, 2019.
  4. Fault and availability statistics, reporting year 2016. VDE, October 25, 2017, accessed on October 22, 2019.
  5. Fault and availability statistics - Instructions - Systematic recording of faults and supply interruptions in electrical energy supply networks and their statistical evaluation. VDE FNN, December 2016, accessed on October 24, 2019.
  6. ↑ Energietechnische Gesellschaft im VDE (ETG): Quality of supply in the German power supply network. VDE analysis, Frankfurt, February 1, 2006
  7. Halloween Space Weather Storms of 2003. (Memento from April 1, 2014 in Internet Archive) NOAA Technical Memorandum OAR SEC-88, Space Environment Center, Boulder, Colorado, June 2004, p. 37, accessed December 17, 2013.
  8. How dangerous are coronal mass ejections? A look back at the Carrington event of 1859
  9. ↑ Stefan Loubichi: 36C3 - more open questions than answers. VGB PowerTech Journal, issue 1–2 / 2020, ISSN 1435-3199
  10. What is a brownout? In: www.next-kraftwerke.de. Retrieved July 20, 2016.
  11. ↑ US legal definition "station blackout"
  12. abEffects of the nuclear power plant moratorium on the transmission grids and security of supply. (Memento from April 23, 2013 in Internet Archive) Report from the Federal Network Agency to the Federal Ministry of Economics and Technology, April 11, 2011.
  13. abMarko Čepin (University of Ljubljana): Assessment of Power System Reliability: Methods and Applications, Springer, 2011.
  14. abPower Blackout Risks - Risk Management Options - Emerging Risk Initiative (PDF; 2.0 MB)
  15. Power failure: precaution and self-help. (Memento of the original from March 4, 2016 in 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 @ 2 Template: Webachiv / IABot / www.bbk.bund.de (PDF) Flyer from the BBK - Federal Office for Civil Protection and Disaster Relief
  16. ↑ Th. Petermann et al .: What happens in the event of a blackout. Consequences of a long and large-scale power failure. (= Studies by the Office for Technology Assessment at the German Bundestag. 33). edition sigma, Berlin 2011, ISBN 978-3-8360-8133-7.
  17. New threats and risks. Security interests and protection of the population. Lecture on March 19, 2009 on the occasion of the 11th DRK Rescue Congress.
  18. Non-public land radio service of the authorities and organizations with security tasks (BOS): Implementation of the BOS radio guidelines at the non-police BOS. Bavarian State Ministry of the Interior, December 2009.
  19. We should consider a cold reserve. (Memento from September 16, 2011 in Internet Archive) Interview with Minister of Economic Affairs Rösler. May 28, 2011. In: FAZ.
  20. ↑ A. Praktiknjo, A. Hähnel, G. Erdmann: Assessing energy supply security: Outage cost in private households. In: Energy Policy. Vol. 39, No. 12, December 2011, pp. 7825-7833. doi: 10.1016 / j.enpol.2011.09.028
  21. Light in the dark: an estimate of the potential damage from power outages in Germany. In: HWWI update. 9, 2013.
  22. ↑ Blackout Simulator
  23. KTA 3701: Superordinate requirements for the electrical energy supply in nuclear power plants. (Memento from December 13, 2013 in Internet Archive) (PDF; 100 kB). April 2004.
  24. ↑ Assessment of the accident risk of advanced pressurized water reactors in Germany (PDF; 8.5 MB), GRS, GRS-175, Oct. 2002 (Section 5.1 Triggering events).
  25. ↑ Federal Network Agency: Continued high security of supply in German electricity networks (PDF)
  26. 12 minutes without electricity. In: Southgerman newspaper. August 21, 2015. Accessed August 21, 2015.
  27. ↑ Federal Network Agency: Power supply quality at a consistently high level in 2015. Press release from October 21, 2016. Quote: "The energy transition and the increasing proportion of decentralized generation capacity continue to have no negative effects on the quality of supply."
  28. ↑ Christoph Pieper et al .: The economic use of power-to-heat systems in the balancing energy market. In: Chemical engineer technology. Volume 87, No. 4, 2015, 390-402, p. 390, doi: 10.1002 / cite.201400118.
  29. ↑ Federal Network Agency: Key figures for power supply interruptions, accessed on April 5, 2018.