Environment Minister Simon Corbell on Friday announced a plan for up to one megawatt of the ACT's electricity to be sourced from a community feed-in-tariff scheme.

Eligible community generators would receive 20¢ per kilowatt-hour for 20 years.

Mr Corbell said people who were unable to install solar panels on their own homes could invest in community schemes with a guaranteed income stream.

''You'll get a return each and every year for 20 years from the renewable energy generation and the feed-in tariff payment that comes with it,'' Mr Corbell said.

''So it's a great opportunity for people to buy into renewable energy generation and get a reasonable return on their investment in the same way that people can now when they put solar on the top of their own home.''

The community power generators would produce the same amount of power that could be expected from 500 household solar panel installations.

Projects could include a mixture of panels on large rooftops and on the ground, or one big solar farm.

Bob Clark, a director of Canberra group SolarShare, which wants to establish a solar farm, welcomed the proposal. Mr Clark said 270 people had invested about $1 million in the project.

''We're negotiating with a number of sites here in Canberra that are already established and also possible greenfields sites to create community solar farms,'' he said.

SolarShare's business model assumes that prospective investors will want a financial return at least equivalent to what they would earn for investing in high-interest savings accounts.

Mr Corbell defended the financial cost to households of the government's ambitious plan for 90 per cent of Canberra's electricity to come from renewable sources.

He said the additional cost would peak at $4 per household by 2019. But many householders would save at least the same amount through government-supported energy-efficiency measures.