EW-I-1 + 2 Weather-related power supply interruptions

2019 Monitoring Report on the German Strategy for Adaptation to Climate Change

Table of Contents

 

EW-I-1: Weather-related disruptions of power supply

Extreme weather events such as the hurricanes Cyril (2007), Xynthia (2010) and, latterly, Herwart and Xavier (2017) became notable markers in the power supply disruption statistics. The proportion of atmospheric impacts in all these cases of disruption and force majeure was clearly striking in those years. Looking at the overall time series, weather-related disruptions indicate falling trends.

Two lines show the percentage of weather-related unplanned interruptions for low voltage and medium voltage from 2006 to 2012. For low voltage, the values vary between 5 and 25 percent, for medium voltage between 44 percent and 6 percent. The values were highest in 2007. In both cases, there is a significant downward trend.
EW-I-1: Weather-related disruptions of power supply

Two lines show the percentage of weather-related unplanned interruptions for low voltage and medium voltage from 2006 to 2012. For low voltage, the values vary between 5 and 25 percent, for medium voltage between 44 percent and 6 percent. The values were highest in 2007. In both cases, there is a significant downward trend.

Source: BNetzA (failure statistics)
 

EW-I-2: Weather-related unavailability of power supply

Compared to other years, hurricane Cyril in 2007 caused severe and extensive damage to the electricity networks. In 2007, this led to a cumulative duration of disruption in power supply of just under an average of 22 minutes per client connected to the grid owing to weather-related events.

The stack columns show the weather-related unavailability of electricity supply in minutes for the end consumer from 2006 to 2017. The values are differentiated for atmospheric effects and force majeure as well as for other unplanned interruptions. In both cases, there is no trend. The values fluctuate between the years.
EW-I-2: Weather-related unavailability of power supply

The stack columns show the weather-related unavailability of electricity supply in minutes for the end consumer from 2006 to 2017. The values are differentiated for atmospheric effects and force majeure as well as for other unplanned interruptions. In both cases, there is no trend. The values fluctuate between the years. The summary values range from 36 minutes in 2007 to slightly more than 13 minutes in 2016. In 2007 and 2013, when the values are highest, the atmospheric impacts and force majeure predominate, in the other years the other unplanned interruptions.

Source: BNetzA (failure statistics)
 

Germany’s power supply – despite climate change one of the world’s safest

The fact that disruptions in power supply are infrequent and very brief shows that Germany has a very reliable power supply. In Germany, the Federal Network Agency (BnetzA/Bundesnetzagentur) is responsible for any disruptions in power supply. As part of its remit the BNetzA evaluates reports made by grid operators on disruptions of more than three minutes’ duration regarding medium and low voltage supply which make up the distribution network. The BNetzA differentiates between various causes of disruption in the supply network. For example, the agency categorises wind and temperature effects or overvoltages due to lightning strikes collectively as ‘atmospheric impacts’. Events of particular severity such as extraordinary floodwater or hurricanes are classed as ’force majeure’. Such events can entail prolonged adverse effects, for when grids are disconnected over long distances, essential repairs can sometimes take a long time.

Germany has one of the world’s most stable electricity networks. Nevertheless, extreme weather events and certain weather patterns can affect the transmission and distribution of electricity. The impacts of hurricane Cyril in 2007 were particularly striking. In that year, the number of disruptions was twice as high as recorded in most previous years. Owing to the weather or certain weather patterns, end consumers were in that year left without electricity for on average just under 22 minutes. By comparison, this value fluctuated between 3 and 7.5 minutes in subsequent years. In 2010 higher figures can be attributed to hurricane Xynthia, and in 2017 the storms named Herwart and Xavier caused disruptions in power supply.

If extreme weather situations – above all severe storms and hurricanes – become more frequent owing to climate change, associated disruptions in power supply may become more frequent too and their duration may increase, unless networks are appropriately engineered and maintained. Whether electricity networks become affected depends, apart from atmospheric impacts, also on the quality, maintenance status and age of technical components used in the network. Since 2010 investments in and expenditure on new installations, expansion, extensions, maintenance and upgrades have increased continuously. This is why grid lines, transformers and circuit breakers used in the German transmission network are considered to be fully functional.52

Likewise, the network structure is also one of the key determinants. So far, approximately 95 % of extra-high and high-voltage transmission lines are routed above ground thus being directly exposed to wind and weather. However, the nodes of this grid are interconnected (meshed). A high degree of meshing contributes to high reliability of supply. In case of the failure of individual lines, the supply can usually be re-routed via other, so-called redundant lines (n-1- safety). This is why the ultimate consumer does not usually suffer loss of electricity supply from disruptions in the transmission network. Effective protection from storms, snow loads or ice loads can be achieved by routing electricity lines (cabling) underground. An Act passed in 2015 on changing the regulations governing the construction of energy networks legalised the underground routing of new extra-high and high voltage cabling by prioritising this type of construction as a planning principle in federal planning regulations. Besides increasing the acceptance of network expansion53 underground cabling also contributes to a higher resilience of networks to climate-related impacts. Concurrently, there is ongoing research on selected pilot routes to establish to what extent underground cabling might be used with regard to three-phase current lines.   

52 BMWi – Bundesministerium für Wirtschaft und Energie 2017: Zweiter Fortschrittsbericht zur Energiewende – Die Energie der Zukunft – Berichtsjahr 2017: 197, 280.
www.bmwi.de/Redaktion/DE/Publikationen/Energie/fortschrittsbericht-monitoring-energiewende.html
53 BMWi 2018: Sechster Monitoring-Bericht zur Energiewende – Die Energie der Zukunft – Berichtsjahr 2016: 134.
www.bmwi.de/Redaktion/DE/Publikationen/Energie/sechster-monitoring-bericht-zur-energiewende.html

 

 

Objectives

Operators’ commitment to operate a safe, reliable and efficient energy supply network (EnWG, § 11 (1))