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UK National Grid: IceLink is feasible, achievable and viable

Economist-Iceland-UK-HVDCAccording to a recent article in the Schumpeter column of the Economist, the proposed IceLink power cable between Iceland and Britain seems to be getting a deservedly serious hearing.

The IceLink would be the longest undersea cable in the world, at at least 1,000 km, costing on current estimates billions of EUR.  According to the Economist It would take four years to construct the cable and would have a capacity of 1,000 MW. And the Economist is very positive about the project:

Iceland is in a unique position with regard to energy: it has in effect unlimited power, from both geothermal and hydro-electric. Apart from keeping the hardy Icelanders warm, it also runs aluminum smelters. But exporting electricty would give the small island economy a new source of income (the main other ones, since the collapse of the financial bubble, are fish and tourism).

HVDC-Cable-Iceland-Europe-map-slideThe Economist goes on by pointing out that the attraction of the IcLink for Britain is flexibility. The increasing dependence on wind energy, which produced a record ten percent of Britain’s power in last December (2013), may be questionable from an economic point of view. And it creates a technical difficulty too: if the wind drops, you need a speedy alternative source of power. When it blows strongly, you need somewhere to store it. Iceland’s stable geothermal- and hydro-electric generation is ideal for both purposes. But Britain has rather little hydro and close to none geothermal.

According to the Economist, the UK National Grid (the transmission operator for electricity and gas) likes the project, describing it as “Technically feasible…Politically achievable…Commercially viable”. Britain and Iceland signed an intergovernmental memorandum of understanding on the project in 2012. In June last year, the project won backing from an UK cross-party government advisory committee. Now the British government is waiting for the Icelandic side to come out with a firm proposal.

University research on HVDC development

The Icelandic Energy Portal is cooperating with Reykjavik University and the University of Iceland, as scientific and educational partners. Thus, we sometimes introduce research by university scholars and students. Today, we will focus on the findings in a recent thesis towards MSc in Industrial Engineering at the University of Iceland, by Ms. Svandís Hlín Karlsdóttir.

University-of-iceland-MSc-Engineering-1The title of the thesis is “Experience in transporting energy through subsea power cables: The case of Iceland”. It analyses the experience from subsea power cable projects in Europe to bring new aspects and gain more information and insights to this project. The main focus is on technology, reliability and environmental impact. In the thesis, this study of the European experience is transferred to Iceland and is evaluated as to which technology is suitable for Icelandic conditions, what to avoid and what to keep in mind, and also to evaluate the reliability of possible subsea power cables from Iceland to mainland Europe, or to Great Britain.


The need for increased renewable energy source utilization has forced the technology forward. Challenges are constantly confronted with new developments in technology. The development in material and manufacturing processes has increased power capacity and voltage rating and made the cables more robust. The cable systems are frequently being laid at greater depth and over longer distances. The maximum power capacity is 800 MW (single cable) at 500 kV or 1,000 MW (two cables) at 320 kV, for mass-impregnated cables and extruded XLPE cables, respectively. The key factors to a successful HVDC subsea power cable project is a thorough marine survey to find the most suitable route and for design of the cable. Great expertise in installation method is also crucial, concerning choice of vessel, equipment and crew.


Savings in investment cost, which could lower the reliability of the cable system, could result in higher operation and repair cost in the future. When a cable is damaged and is in need of repair, there is always need for a specialized vessel, equipment and crew. That is independent on the size of the damage and could therefore be a big part of the repair. The time waiting for weather can also be very expensive. Additionally there is loss in revenues when no power is transmitted. Those considerations must be optimized during planning and designing of a cable project.

With prior experience and development of subsea cable systems the reliability has improved. From 1986 to 2009 the reliability has improved from 0.264 failures/year/100km to 0.100 failures/year/100km. Operation procedures with real-time monitoring improve maintenance of the system which can prevent major damage to occurring, resulting in better reliability and longer life time of the system.

Environmental impact

When implementing such a large complex electrical system there are always concerns about the environmental impact. According to the latest researcher and environmental impact assessments in Sweden there are no threats to the surrounding area and it will not suffer permanent damage, from installation and operation of the cable. Latest technological developments have decreased the electrical magnetic field and improved installation methods. The magnetic field is so low that sensitive marine life and ship compasses have not been influenced in a bad way, according to the latest research.

The case of Iceland

The cable route from Iceland to mainland Europe will lay under the North Atlantic Ocean passing the Faroe Islands and will be approximately 1,170 km long and reach a depth of 1,200 m. The suitable technology for Icelandic conditions is two mass-impregnated single- core cables, each transmitting 500 MW at 400-450 kV in a bi-polar configuration. That solution improves reliability and eliminates magnetic fields. It is recommended to have copper conductor at the shallower parts and aluminum for the deeper colder part because of the increased laying tensions. Cable burial of at least 2 m is recommended for the whole route to protect against external violence where possible.

University-of-iceland-MSc-Engineering-2The failure rate for the subsea cable between Iceland and mainland Europe is estimated at 0.1 failure/year/100 km which results in 1 failure a year. The outage duration for each repair is dependent on fault location and weather conditions. For a fault location near shore there is more accessibility of weather window which reduces outage duration. The outage duration is higher far offshore but there is also less probability of damage, as the cable will be laid at great depth. The availability on the subsea cable is variable between seasons and locations. During winter the access to repair is less than during other seasons. The average unavailability of the system due to damage is estimated at 12% but with less probability of damage at great depth the unavailability is less, or near 10%.

If sensitive marine species can be avoided along the cable route, the environmental impact is estimated to be low. There is no relation between magnetic fields of HVDC subsea cables and threat to marine life and with the cable type recommended there is no danger of chemical impact, or oil leakage. By laying the cables close together the magnetic fields can be eliminated. Landmarks on the sea bottom formed during cable burial is said to recover in approximately one year.

Future work

Developments in technology are of special interest. Future technology like superconductors and advanced maintenance tools being developed will increase power capacity and minimize duration of outages, resulting in more asset feasibility. Also, the expected future development of extruded XLPE cables will be of importance. Possible future projects could consist of more specific analysis of the sea state to evaluate suitable routes based on reliability of different locations and to collect real operation data from the owners and operators of the HVDC subsea cable systems.

UK National Grid showing interest in IceLink

According to news from Norwegian energy information provider Montel, the cost of electric power from the potential subsea interconnector linking the UK with Iceland  will be around GBP 100/MWh (164 USD/MWh). This new subsea cable, which is sometimes referred to as the IceLink, would thus offer electric power at substantiall lower prices than for example from offshore wind.

Icelink-HVDC-UK-NG-nov-2013-5The IceLink would be a high voltage direct current (HVDC) cable, with a power capacacity of 700-1,000 MW.  It would be 1,000-1,500 km long, making it qute a bit longer than any existing subsea cable of this kind today. The longest subsea electric cable is currently the 580 km NorNed cable between Holland and Norway. Longer cables of this type are being planned, such as a cable between Norway and the United Kingdom that will be more than 700  km long, and even longer cables in the Mediterranean.

Mr Hörður Arnarsson, CEO of the Icelandic  state owned power company Landsvirkjun has expressed that the Icelink cable could add “very valuable” flexibility to offset intermittent renewables production in the UK. Landsvirkjun generates 75% of all electricity used in Iceland.

Icelink-HVDC-UK-NG-nov-2013-4In May 2012, Icelandic and UK ministers signed a memorandum of understanding over a new interconnector between the countries. The UK TSO National Grid has been showing interest in the Icelink, focusing on issues such as supply diversification, and gaining access to the reliable hydro- and geothermal energy resources of Iceland.

In the last few months,Mr. Paul Johnson, Project Director and Head of Cables at National Grid, has at numerous occasions expressed that the need for such an interconnector between Iceland and the UK has come to the fore. According to Mr. Johnson, the IceLink is a realizable goal and there is political will for the connector. Mr. Charles Hendry, MP and former UK Energy Minister has been of the same opinion, as the IceLink project offers low-risk, predictable returns attractive to investors, such as pension and infrastructure funds.


According to Montel, the costs of the IceLink are estimated at GBP 4 billion, with it being possibly completed by 2022. The project could supply up to 5 TWh of power annually to Britain from hydro, geothermal and wind sources in Iceland.

While Icelanders still need to engage in national discussions about the costs and benefits of a subsea power cable to the UK, policy makers in the UK seems to agree on the project. In addition, the President of Iceland, Mr. Ólafur Ragnar Grímsson, has addressed leaders and people in the energy business, expressing his view that the Icelanders and the Brits should jointly examine the options of an interconnector.

Iceland-UK-BICC-meeting-Nov-2013-ORG-2At an energy conference in London in last November (2013), Mr. Grímsson said the proposed IceLink should be hard-headed analysis driven by engineers and energy specialists. “We should listen to the government in Britain…then in two to three years we can come back to the table and make the real decision.”

Grimsson said popular support was necessary before a project to bring geothermal power from Iceland to the UK could get off the ground. “As we move forward we need to bring all segments of Icelandic society into this discussion,” he said. “Then we will take a decision based not only on the business sense and the technical feasibility [of the project] but on the national will,” Grimsson said, adding that unless “there is a broad national will behind this, you will never get the necessary players on board”.

The three slides above are from a presentation given by Mr. Paul Johnson from UK National Grid, at the Bloomberg Icelandic Energy Summit. It took place in London on November 1st 2013.

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