Jan. 26 (UPI) -- Britain and nine other northern European countries committed Monday to building a massive 100 Gigawatt offshore wind project in the North Sea to transform its spent oil fields into a "reservoir" for clean energy over the next 25 years.

Energy ministers from Britain, Belgium, Denmark, France, Germany, Iceland, Ireland, Luxembourg, the Netherlands and Norway signed onto the deal -- the Hamburg Declaration -- at a meeting in Hamburg, Germany, that will see them build windfarms producing electricity sufficient to power 143 million homes via high-voltage undersea cables.

U.K. Energy Secretary Ed Miliband said that by securing clean energy for the future Britain was backing its national interests, enabling it to get off the "rollercoaster" of fossil fuels.

The commitment is part of the so-called "Ostend Declaration" in 2023 to add 300 Gigawatts of offshore wind-powered electricity generation by 2050, with the Brussels-based WindEurope trade body forecasting Monday's agreement could pull in as much as $1.2 trillion of investment by 2040.

European Commission and NATO officials were also at the meeting in Hamburg for discussions on protecting energy infrastructure offshore due to growing fears over adversaries' efforts to tamper with underseas pipelines and cables.