The world's longest undersea electric cable
Norwegian Statnett and British National Grid are planning a 1.400 MW sea cable between Norway and the UK. At 800 km, it will be significantly longer than the current record holder, the 580 km cable between Norway and the Netherlands.
Connecting the dots: Cables between the Nordic countries and the rest of Europe will increase energy security for all parts.
In recent years, Norway has experienced huge variations in the electricity price during the winter. With 97% of the country's electricity coming from hydropower, the market is heavily dependent on precipitation levels. With too much rain, they risk flooded reservoirs, and can't make use of all the energy. With too little rain the reservoirs might empty out before the spring melt – especially if demand is high because of a cold winter.
In the UK, on the other hand, electricity production is based on thermal energy such as coal and nuclear power. These sources are hard to regulate to match daily variations in consumption. The UK is planning to increase renewable electricity production from 1.8% of total production in 2007, to 20% in 2020. Almost all of it will be wind. This adds further challenges to matching daily production with consumption, as wind turbines only produce energy when the wind blows, with no means of storing it for later use.
The countries face different problems, but connecting the two grids could make it easier for both of them. While the UK needs more flexible power to compensate for daily variations, Norway needs energy that is less dependent on the time of year. Now, grid operators in Norway and the UK have joined forces to build a cable from Kvilldal, on the South-Western coast of Norway, to the Newcastle area in England. This will make it possible to avoid extreme prices during the winter in Norway, or on windless days in the UK.
Kvilldal hosts Norway's largest hydropower plant, with an installed capacity of 1240 MW. It is connected to the 640 MW Saurdal plant, where two of the four turbines are reversible, meaning that they can pump water back up into the reservoir, which has room for enough water to store 7.9 TWh of energy, about the same as the UK's total energy production for one week. This way, the Kvilldal-Saurdal system is capable of storing excess wind energy from England and even send it back again when it's needed. This prevents the reservoirs from emptying too fast in dry years or cold winters. It makes a better use of the available energy resources, raising the total possible amount of renewable energy in the system and increasing energy security for both countries.
The cable is expected to be ready between 2017 and 2020. It is one of many cables expected to connect Norway's electricity grid closer to the rest of Europe, and could eventually be part of an offshore power grid in the North Sea.
