Power grid main characteristics
The Elia Group is organised around its two major constituent electricity transmission system operators: Elia in Belgium and 50Hertz Transmission in Germany.
Elia, the Belgian transmission system operator, holds licences for its 380 kV to 150 kV national grid and for its 70 kV to 30 kV grids in Belgium’s three regions and operates about 8,400 km of lines and underground cables.
50Hertz, one of Germany’s four transmission system operators and active in the north-eastern part of the country, is held jointly by Elia (60%) and Industry Funds Management (40%). The grid covers an area larger than 109,360 km² and runs a length of approx. 9,995 km – It is the technical backbone that reliably supplies power to more than 18 million people.
The Elia Group is one of the top five transmission system operators in Europe and one of the top 15 in the world. It actively sets an example as a driving force behind the development of the European market and through its commitment to ensuring reliability and security of supply and its efforts to promote the integration of renewable energies.
Their certifications as fully unbundled transmission system operators in Belgium and Germany prove their ability to operate completely independently from electricity generators and suppliers. This is an essential prerequisite for the creation of a properly integrated European market.
Given its strategic position at the crossroads between electricity markets in western, eastern and northern Europe, the Elia Group securely manages imports, exports and transits of electrical energy over its grids. It also plays a key role in integrating European electricity markets by participating directly and indirectly in the shareholder structure of Eurogrid International, the regional cross-border flow monitoring centre Coreso, the APX-ENDEX-Belpex and EPEX Spot power exchanges, the CASC.EU and EMCC capacity auction offices and the Gridlab training centre.
Major incidents & preventive measures
The main European electrical shortage
On November 4th 2006, Europe experienced a major network incident originated in Germany. One of the German transmission system operators switched off the 400,000 volt power line that crosses the River Ems in the north of the country, to allow a ship to pass through. Electricity transmission flows were instantly redistributed on the remaining lines. Becoming saturated, those lines tripped in what is known as a “cascade”. Many power lines in Germany, Austria, Hungary and Croatia were automatically disconnected, enventually leading to a major unbalance and the split of the continental synchronous system in 3 zones characterized either by power shortage or power excess. Ultimately, the entire European continent was affected by load shedding: altogether, some 15 million homes were without deprived of power for up to one hour.
Since that incident, Europe’s transmission system operators have taken a number of measures. They have strengthened their technical cooperation. In 2008, several TSO’s created a European grid technical coordination centre in Bruxelles (Coreso) which provides constant analysis of system security and monitors Europe’s power networks in real time in order to prevent electrical disturbances. 50Hertz is also an active member of the Transmission System Operator Security Cooperation (TSC) which was launched in December 2008. With the common goal of enhancing overall system security, TSC harmonises perfectly with other intra-European initiatives and cooperation centres.
2012, Belgium: Freak winder weather
On 5 March, the Belgian transmission system was hit by freak winter weather. An unusual combination of meteorological conditions damaged a number of high-voltage pylons, cutting off power for several hours in the area of the city of Tournai. Elia very quickly decided to deploy its new backup line to supply emergency power in case that an incident would occur during grid restoration works.
4 October 2012, Pulgar (Germany): Tornado damages transmission towers
Transmission towers of 50Hertz belonging to the 380-kV line between Pulgar and Vieselbach are heavily damaged by a tornado in the local area. Experts from 50Hertz bring the situation under control immediately, thus preventing any bottleneck in supply.
24 October 2012, Machelen (Belgium): Incident at the Machelen high-voltage substation
On 24 October, during commissioning operations, a technical incident triggered an explosion at the Machelen 3 150 kV substation. This led to a short-circuit and a sudden and momentary voltage dip across the entire grid. Supply on the Elia grid was restored immediately, but some customers (such as SNCB, Belgacom) experienced difficulties due to the triggering of protection relays which led to a momentary cut in their electricity supply.
28 October 2012, Belgium: Disconnection of offshore wind farms during storm
During the storm on 28 October, winds on the sea rose above the offshore wind farm disconnection threshold, triggering the full shutdown of 450 MW in generating capacity. On 31 October, a similar phenomenon arose following a sudden change in wind, offshore wind generation suddenly dropped by 350 MW. The two fluctuations were offset by internal control systems and processes established by Elia.
5 and 6 December 2013, Northern Germany: Challenging situation due to Hurricane “Xaver”
The effects of Hurricane “Xaver” were a special challenge for the system management of 50Hertz on 5 and 6 December 2013. Maintaining control of the grid situation required the preparation and implementation of increased security requirements in a targeted manner in the transmission system as well as redispatch measures with conventional power plants. To a lesser degree, reductions in the input from wind farms also contributed. “Xaver” caused 53 weather-related trips in lines and other 50Hertz grid elements, but there was only a single case of a brief supply interruption.