Denmark is working steadily towards a green transition and procuring the majority of the country’s energy supply from renewable energy (RE) sources. In particular, electricity from solar and wind broke a record in 2019 and amounted to about 50 per cent of Denmark’s electricity consumption.
The transmission system operator (TSO) Energinet.dk is striding towards strengthening the grid to incorporate the influx of RE and thereby contribute to the acceleration of the green transition. It is exploring ways to more efficiently harness the abundant RE, which will aid its progress towards a climate-neutral future.
In December 2019, Denmark’s Parliament passed the Climate Act, with a target to reduce greenhouse gas (GHG) emissions by 70 per cent by 2030 (compared to 1990 levels), and a commitment to reach net-zero emissions by 2050 at the latest. In order to overhaul Denmark’s climate policy, the Act also enables the Danish Government to present Climate Action Programmes every year with concrete political initiatives to decarbonise sectors such as transportation, agriculture and energy.
In the backdrop of the Climate Act, Energinet.dk is steadily working towards its new strategy ‘Winds of Change’, which is a development strategy to recognise instruments that must be used to reach 100 per cent green energy consumption by 2050. Though the strategy is still being monitored and is yet to be finalised, it designates four potential areas that need to be pursued in order to ensure a smooth energy transition in the country—focus on large-scale offshore wind, sector coupling (including Power-to-X), solar energy and onshore wind energy.
Apart from this, the TSO is pursuing a long-term development policy, which focuses on dismantling the country’s entire 132 and 150 kV grid network (3,200 circuit km) and replacing it with a new underground network (2,900 km) over the next two decades.
Energinet.dk owns and operates electricity and gas transmission grids in Denmark. The company is responsible for maintaining security of supply and energy markets. Its operations are regulated by the Danish Utility Regulator (DUR) while the Danish Energy Agency is responsible for maintaining the overall efficiency of the sector.
The TSO’s transmission network consists of 132 kV, 150 kV and 400 kV alternating current (AC) lines and 250 kV–500 kV direct current (DC) lines. Its grid is divided into two parts—Denmark West and Denmark East, which have been connected by the Great Belt Cable since 2010.
At the end of 2019, the company’s grid network comprised an estimated 6,200 circuit km of 132–400 kV lines, 40,668 MVA of transformer capacity and 187 substations. During 2015–19, the transmission line length (132 kV to 400 kV) grew at a compound annual growth rate (CAGR) of 0.63 per cent, from 6,007 circuit km in 2015 to about 6,200 circuit km in 2019. The transformer capacity grew at a CAGR of 2.07 per cent during 2015–19, from 36,700 MVA in 2015 to 40,668 MVA in 2019. The number of substations increased at a CAGR of 0.32 per cent during the same period, from 184 in 2015 to about 187 in 2019.
In 2019, Energinet.dk reported a total revenue of DKK2,652 million for its power system segment. During 2015–19, revenue declined at a CAGR of about 3 per cent. During 2015–18, the earnings before interest and tax (EBIT) declined at a CAGR of 18 per cent. The decline in revenue from DKK3,407 million in 2017 to DKK2,652 million in 2019 can be attributed to the deteriorating power transmission infrastructure in the country and a lower realised bottleneck revenue.
|Earnings before interest and tax (operating profit/loss)||232||138||388||104||NA|
Note: All financial data relates to the power system segment (stand-alone figures) of Energinet.dk.
Source: Energinet.dk; Global Transmission Research
Improvement in IT infrastructure
Notably, the company is taking several measures to protect its information technology (IT) infrastructure against cyberattacks, which can significantly threaten grid security. To this end, Energinet.dk is currently strengthening its IT and information security, making it more robust in order to pace up the green energy transition. Digitisation is also expected to play a key role in the development of the future energy system. In particular, the Danish grid relies on a Computer Emergency Response Team (CERT)—a joint monitoring and incident response organisation, operating in collaboration with Dansk Energi (business and interest organisation for energy companies in Denmark) and the Danish District Heating Association (organisation representing the Danish district heating companies).
Over the past three to four years, Energinet.dk has adopted various measures to significantly strengthen the grid against cyber threats—setting up the Audit and Risk Committee (in September 2018); automating controls allowing insight into the vulnerabilities in IT systems; and new operating models enabling greater protection at substations. As a result of such measures, the information security of Energinet.dk improved from 3.1 in 2016 to 4.0 in 2019 on the Capability Maturity Model Integration (CMMI) scale (ranging from 1 to 5). The CMMI scale analyses the potential risks facing an organisation’s ability to identify and deal with possible cyber threats, helping the organisation plan its future cyber investments.
Reinvestment, Expansion, Restoration plan
Denmark’s aging infrastructure poses a major challenge, hampering the security of power supply throughout the country. This calls for reinvestment in the electricity infrastructure by the TSO. Energinet.dk’s RUS (reinvestment, expansion, restoration) Plan 2018 (published in August 2019) highlights the need for, and the adequate measures to be undertaken for reinvestment, expansion, restoration and re-engineering of the electric grid in the medium term (2018–28) in Denmark.
The need to reinforce the grid coincides with growing RE production, increased power trade relations between neighbouring countries and a rise in consumption.
About DKK43 billion has been allocated to improve the transmission grid, of which DKK8.3 billion is for reinvestment in the grid, DKK30.6 billion for expansion of the grid and DKK4.1 billion for redevelopment/renovation of the grid. The break-up for reinvestment, expansion and redevelopment into different phases of investment—ongoing (2019-24), planned (2020-25) and possible (2019-28)—is shown in the figure below.
Some of the projects critical for grid reinforcement include the establishment of 400 kV lines between various substations, including Landerupgård and Revsing, Bjæverskov and Hovegård, Ferslev and Tjele, as well as use of 400 kV systems on the new overhead line between the Endrup and Idomlund substations. Further, the grid needs to be reinforced between the islands of Lolland and Falster as a result of RE expansion, which can be realised by 220 kV cable connections.
The green transition calls for a greater need to expand the electricity infrastructure. To enable this, Energinet.dk is working with universities and manufacturers on its DANish Power system with AC Cables (DANPAC) 2020 research project to develop new underground cable laying technology and study ways in which the utilisation of cable capacity can be improved. Alternatives to 400 kV overhead lines in various parts of the country, especially the western part of Jutland, are being explored.
In particular, in the short term, DANPAC 2020 aims to lay underground cables in 15 per cent of the new 400 kV section in West Jutland island. Technical inspections related to the undergrounding of lines are underway as underground cables are costlier to lay than overhead lines and also possess different properties—anticipated to cause ‘too much’ noise in the power grid.
Utilising large-scale offshore wind
Denmark is making steady headway in utilising the abundant potential of offshore wind energy in the country. It is strengthening its position in the European energy market via power generation from large-scale offshore wind and engaging in power trade with its neighbouring countries.
In July 2020, a milestone was achieved when the Kriegers Flak Combined Grid Solution (CGS) interconnector project marked the successful transmission of power between Germany and Denmark. The project is the world’s first offshore interconnector incorporating the use of national grid connections of offshore wind farms to connect the power grids of two countries. The project is being developed by Energinet.dk and 50 Hertz (Germany’s grid developer). The interconnection project aims to secure power transfer between the Danish island of Zealand and the state of Mecklenburg, West Pomerania, in Germany. Specifically, the 400 MW project will connect the Kriegers Flak (Denmark) and Baltic 2 (Germany) wind farms, which are about 30 km apart, via two high voltage alternating current (HVAC) sea cables (at 150 kV and 220 kV). It also includes the installation of a back-to-back (B2B) substation in Bentwisch near Rostock, Germany.
In August 2020, Denmark’s Ministry of Climate, Energy and Utilities approved the EUR3.8 billion investment plan of Energinet.dk. Of this amount, a major part will be invested in the Viking Link—a high voltage direct current (HVDC) link between the UK and Denmark. The 740-km link will connect Revsing in South Jutland (Denmark) and Bicker Fen in Lincolnshire (UK). Energinet.dk is developing the project with its UK TSO counterpart National Grid’s subsidiary National Grid Viking Link Limited (NGVL). The link is designated as a Project of Common Interest (PCI), and is scheduled for commissioning in end-2023.
Sector coupling using Power-to-X
Energinet.dk believes that sector coupling is key to a climate-neutral future. Sector coupling refers to the integration of the energy consuming sectors—buildings (heating and cooling), transport and industry—with the power producing sector.
Energinet.dk is working towards achieving sector coupling via Power-to-X, which describes methods to convert electrical energy into liquid/gaseous chemical energy sources. It typically refers to how electricity can be converted to different energy sources utilising surplus electric power during periods when fluctuating RE generation exceeds load. At peak power production times, electricity could be used to produce hydrogen or synthetic gas (power-to-gas). The gas that stores the energy can either be used to fuel vehicles or it could be turned back into electricity or heat in times of little sun and wind. The company has set a strategic goal to establish a large-scale hydrogen storage business within the next few years.
Future investment plans
In 2019, major investments made by Energinet.dk in the transmission segment included investments in foreign relations with the Netherlands (COBRAcable) and Germany (Kriegers Flak), reinvestments in the 132/150 kV network and connection of coastal turbines.
The 700 MW Copenhagen–Brussels–Amsterdam (COBRAcable) interconnector between the Netherlands and Denmark—inaugurated in November 2019—was developed in collaboration with the Netherlands’ TSO TenneT. The subsea link connects the HVDC voltage source converter (VSC) stations built in Eemshaven (the Netherlands) and Endrup (Denmark). The cost for the Danish section of the COBRAcable was DKK2 billion.
Further, according to Global Transmission Research estimates, the TSO has plans to add approximately 1,007 circuit km of transmission lines during 2020–30, of which about 802 circuit km are planned to be added during 2020–25 and the remaining are expected to be added during 2026–30. During 2020–30, about 8,075 MVA of transformer capacity is planned to be added and 15 new substations are expected to come up.
According to the Nordic Grid Development Plan 2019, Denmark is set to execute various domestic (mostly 400 kV lines) and cross-border transmission projects of significance.
A key domestic project to be reinforced is the 400 kV Endrup–Idomlund line. With the planned offshore wind farms on Horns Rev 3 and the North Sea South and North, the existing high voltage grid in West Jutland is not strong enough. To facilitate better power transmission, Energinet.dk will replace the existing 150 kV overhead line (OHL) between Karlsgårde and Idomlund with a new 400 kV OHL between Endrup and Idomlund.
Amongst cross-border projects, the TSO is planning to link the Danish grid with Germany and UK. Denmark is seeking two grid connections with Germany via the east coast and west coast projects respectively. With the UK, the country has commenced work on the 1,400 MW HVDC Viking Link.
|400 kV Endrup–Idomlund line||Replacing the existing 150 kV OHL between Karlsgårde and Idomlund with a new 400 kV OHL between Endrup and Idomlund||Under public consultation||2023|
|400 kV Revsing–Landerupgaard line||Transmission line required to ensure power supply to the eastern part of Jutland and Funen||Under consideration||2024|
|400 kV Bjæverskov–Hovegård line||Transmission line required to ensure evacuation of power associated with the Kriegers Flak offshore wind farm||Under consideration||2023|
|Denmark West–Germany link||On the Denmark West and Germany border there are two projects— The east coast project—a new 400 kV line from Kassoe to Audorf, increasing the capacity on the border to 2,500 MW in 2020. The west coast project—a double 400 kV line from Endrup to Klixbüll where it will connect with two 400 kV lines being built along Germany’s western coastline in Schleswig Holstein; the project increases the possibility of exporting and importing power on the border from 2,500 MW to 3,500 MW in 2023.||Under construction Planned||2020 2023|
|Viking Link (Denmark West–UK)||A 740-km HVDC link (1,400 MW) will connect Revsing in South Jutland (Denmark) and Bicker Fen in Lincolnshire (UK)||Under construction||2023|
Note: HVDC: high voltage direct current; OHL: overhead line
Source: Energinet.dk; Nordic Grid Development Plan 2019; Global Transmission Research
Denmark is progressing steadily towards a green transition, exploring innovative solutions and undertaking initiatives to strengthen the grid in order to incorporate the upcoming RE capacity.
Combating the challenge of aging infrastructure, the TSO is undertaking measures for the reinvestment, expansion and restoration of the grid. Energinet.dk is also working to strengthen the resilience of its IT infrastructure against cyberattacks to ensure grid security.
To harness the abundant offshore wind, Energinet.dk is investing in offshore wind integration. The TSO is thus gaining a strong foothold in the European energy market, engaging in power trade with neighbouring countries via the establishment of cross-border interconnections to optimise energy utilisation.
The article has been sourced from Global Transmission