Scotland has approved ten marine energy projects that leaders predict could provide electricity for one-third of the nation’s homes by 2020 and make Scotland the world leader in wave energy. The government awarded leases to companies to construct six wave energy projects and four tidal projects off the Scottish coast in what experts say would be the first developments of their kind on a large commercial scale. Construction would cost £4 billion ($6.1 billion) and require another £1 billion ($1.53 billion) in government funding to upgrade the national electric grid. But First Minister Alex Salmond said tapping into the resources of Pentland Firth, a strait north of Scotland that is known for its strong tides, can make the country the “powerhouse of Europe.”