The U.K. and Norway are on track to build the world’s longest power cable. Electric-grid operators from both countries have agreed to build a $2 billion transmission line to link the nations’ power systems.

Norway’s grid operator Statnett SF and the U.K.’s National Grid said the interconnector will stretch 450 miles across the North Sea and have the capacity to move 1,400 megawatts of electricity -- enough power to light up around 750,000 British homes, according to the Thursday announcement.

The connection will allow the U.K. to increase its share of renewable energy supplies. When Britain’s wind turbines aren’t spinning and producing power, National Grid can draw on Norway’s hydropower supplies, instead of from coal- or natural gas-fired power plants. The additional megawatts will boost National Grid’s overall power capacity, enabling the company to lower electricity prices in the middle of the day when demand is highest.

“Access to low-carbon energy from Norway hydropower stations will help us meet the challenge of greener, affordable energy,” Alan Foster, director of European business development for National Grid, said in a statement. “It also adds to the diversity of energy sources for U.K. and potentially can reduce peak prices with benefits for consumers and businesses.”

The power cable could be completed in 2021. Statnett and National Grid said they will share the investment.

The U.K. power grid is already linked to France, the Netherlands, Ireland and Northern Ireland, with 4,000 megawatts of exchange capacity, or about 5 percent of the total U.K. generation capacity, the Wall Street Journal noted. The U.K. aims to boost that amount to 10 percent of total capacity, in line with the European Commission’s proposed benchmarks.

National Grid in February signed a joint venture agreement with Belgium’s grid operator for a 1,000-megawatt power cable between the countries. The U.K. power company is also considering a separate link to Denmark. The cross-country connections are part of a larger European strategy to broaden the continent’s electricity market, which will help to smooth out power flows as countries increase their shares of intermittent wind and solar power.

“Better electricity links to our neighbors help to guarantee our energy security at the lowest possible cost to bill payers and means we can use renewable electricity more effectively, allowing excess generation to be exported,” UK Energy and Climate Change Secretary Ed Davey said in a Feb. 27 statement.