The Green Party has pledged to set up a publicly-owned entity to boost investment in renewable energy and ensure affordable power and energy security.Co-leaders Chlöe Swarbrick and Marama Davidson unveiled the party's energy policy at the Dunedin Gasworks Museum on Monday, the site of the country's first and last place to manufacture coal gas.They promised to make power bills more affordable by making it easier for renters and homeowners to generate their own power, and set up and fund the new entity called KiwiPower using $980 million from the party's "super-rich tax" over four years.KiwiPower would start with $100m a year for operating costs and $142m a year for new investment.The policy also includes zero-interest clean energy loans to install solar and batteries for up to 90 percent of homeowners, legalising plug-in solar and investing $80m into renewable energy for Māori housing.It would also expand government grant programme Warmer Kiwi Homes to offer more upgrades to make more low-income homes warm, dry and energy efficient, costing $969.8m over four years for 50,000 upgrades.The party promised for solar to be installed on more than half of all public homes within four years at a cost of $460m and to invest $200m for community energy projects, which the party said would be funded by reallocating subsidies for fossil fuel companies.Swarbrick said the market and successive governments had failed to deliver affordable, secure, renewable power."200,000 households are unable to afford to heat their homes while four big power companies control over 85 percent of the market and rake in massive profits," she said."A warm, dry home powered by clean energy should be within everyone's reach. That is the country we can build, and this is how we do it."The plan would lower bills, cut emissions and put power back in the hands of New Zealanders and could be funded by making corporations and the super rich "pay their fair share", Swarbrick said."KiwiPower will invest directly in new renewable generation and sort out our dry-year problem sensibly, without a billion-dollar LNG facility, and support new, independent players coming into the market."Swarbrick said the Greens had chosen to launch the plan at the Dunedin Gasworks Museum because gas belonged in a museum rather than in modern policy.Davidson said the plan gave back ownership to communities and invested in Māori and public housing."Tangata whenua are two to three times more likely to face energy hardship," she said."This is about rangatiratanga over energy and it is part of our enduring commitment to Te Tiriti o Waitangi."The Greens also promised to reform pricing so households and businesses with solar received a fair price for the electricity they exported back to the grid, and establish a renters' right to install solar so they would not be unreasonably blocked.