Water hyacinth has choked off large parts of Lake Victoria, a fresh water lake that straddles Kenya, Uganda and Tanzania, and has alarmed environmentalists with its spread over the past two decades.

The government has had little success in eradicating the weed, which now covers the lake's surface like a carpet of grass, cutting off local communities from vital fishing grounds and choking regional ports.

The project will be developed in phases and it is envisaged having annual capacity to produce 35 megawatts when completed. Construction is due to start this year and is expected to last 12-18 months, an official at the company said.

The first phase will have 8 MW of capacity and the plant will be located in the western county of Homa Bay.

The power plant will use the bio-gas method, harvesting the hyacinth, using bacteria to break the sugars in the weed into methane gas that can then be burnt to produce electricity, Chris Evans, an associate at Equinox, told Reuters.

He said the company is negotiating with Kenya Power , the country's main electricity distributor, to allow it to inject the electricity into the national grid.

(Reporting by Duncan Miriri; Editing by David Goodman)