In 2017, Danes had power in their sockets 99.995 per cent of the time. This means that an average consumer experienced slightly less than 25 minutes of power outage. This is slightly more than in 2016, but the figure is still very low and one of the best in Europe. The high Danish security of electricity supply primarily owes to undergrounding of cables in the distribution grids.

In 2017, outages added up to 25 minutes, and 92 seconds of these resulted from incidents in the transmission grid. Consequently, Energinet did not meet its target of limiting outages for Danes in a normal year due to faults in Energinet’s transmission grid to 60 seconds. The transmission grid fault that affected the most consumers occurred at Svanemøllen station in Copenhagen in October 2017. The fault was caused by a procedural error in connection with planned maintenance at the station and resulted in the disconnection of 92,000 consumers for approx. 25 minutes. 

Significant changes coming
The Danish and European electricity systems are currently undergoing significant changes. Extensive wind and solar power capacity is integrated into the electricity systems, while many traditional thermal power stations are phased out. As more electricity interconnectors link different countries' electrical grids together more closely, the security of electricity supply becomes an increasingly regional, and not simply national, issue. At the same time, electricity markets and operational collaboration across Europe are harmonised via new European regulations. This all greatly influences how Energinet will ensure the Danish security of electricity supply in the future.

Special focus on Copenhagen and Eastern Denmark
Particularly in the Copenhagen area, the security of electricity supply is challenged by, for example, an ageing electricity grid with still longer outage times due to regular maintenance. In addition, electricity consumption is expected to rise while electricity generation from local thermal power stations will decrease.

To meet these challenges, Energinet is establishing new electricity lines into Copenhagen, and expects to put the first into operation in early 2019. Until these first new connections are in operation, Energinet finds that the risk of consumer disconnections is unacceptably high without additional remedial measures, explains Anders Pallesen Jensen, head of the Security of supply department in Energinet’s Electricity System Operator division. "In order to ensure a continued high level of security of electricity supply in Copenhagen, we have ordered a thermal power station to run since the summer of 2017 and will continue to do so until work to reinforce the grid leading into Copenhagen has been completed," he says.  

Overall, security of electricity supply is more vulnerable in Eastern Denmark than in Western Denmark. This is because Eastern Denmark has fewer interconnectors and less generation capacity. As a result, the risk that consumers’ demand for electricity will exceed supply in the coming years increases, if no remedial measures are introduced. 

Søren Dupont Kristensen, managing director of Energinet’s Electricity System Operator division, explains that Energinet is working on several solutions and measures to maintain the current high level of security of electricity supply in Eastern Denmark. These solutions include better utilisation of infrastructure and an upgrade of the Eastern Danish electricity grid by the Øresund Link to Sweden. 

In addition to these operational and infrastructural measures, Energinet also works determinedly to introduce several electricity market reforms, aimed at ensuring greater flexibility of both power generation and consumption. It is, however, not certain when these measures will take full effect. As a consequence of this uncertainty, Energinet has decided to work to establish a strategic reserve in Eastern Denmark. 

 "We will enter talks with Danish and international authorities to get permission to establish a time-limited strategic reserve, which will help to secure that electricity consumers still have power in very critical situations, where the traditional electricity market cannot balance consumption and production," he says.

Read the report: Security of electricity supply report 2018