TORONTO (Reuters) - Ontario gave the green light to four electricity projects on Wednesday to provide a cleaner supply of energy and help meet power demand as the province shutters older coal-fired plants.

The projects, slated to be operating by the end of 2007 and valued at C$1.1 billion ($887 million), will have combined generating capacity of 1,675 megawatts which is enough to power 650,000 homes in the province.

"It's a strong sign that investors are regaining confidence in Ontario's electricity sector," Dwight Duncan, the province's energy minister told a press conference in Toronto.

Two natural gas-fired generating plants -- the Greenfield Energy Center and the St. Clair Power -- are expected to replace most of the capacity of the Lambton coal-fired generating station.

Independent U.S. power producer Calpine Corp and Japan's Mitsui & Co will build the $500 million 1,055-megawatt Greenfield.

St. Clair Power, which is expected to have a capacity of 570 megawatts, was submitted by energy development company Invenergy and its investment partner, Stark Investments.

The Greater Toronto Airports Authority's cogeneration project in Mississauga will have a capacity of 90 megawatts and a project by Loblaw Properties, a unit of Loblaw Cos. Ltd. will result in 10 megawatts.

The ruling Liberals launched a request for proposals last June for 2,500 megawatts of new electricity capacity and received 33 bids representing 8,800 megawatts of capacity.

The province said it is still addressing issues with other selected proponents and expects to make announcements in coming weeks. Until that time, the government said it would not detail how much consumers would pay.

($1=$1.24 Canadian)