The Housing Board is working on its largest single solar-leasing project to date - and is also looking into households being able to buy electricity made from the sun's energy.
Last month, it called its largest solar-leasing tender: for a company to own and operate panels on some 125 blocks in Ang Mo Kio, Sengkang, Serangoon North and Buangkok.
These would produce 5MW of electricity in optimum conditions, or 5 megawatts-peak (MWp), enough to power more than 1,000 four-room HDB flats.
The HDB will offset up to 30 per cent of the start-up costs, and, in turn, buy the electricity for 20 years at a 5 per cent or greater discount off the prevailing market price. This electricity would power lights in corridors and common areas, lifts and water pumps, among other things.
Another tender in May, to generate 2MWp for 40 blocks in Jurong East, includes a possible new option of allowing households to buy the excess electricity generated during the day, again at a discount off the market rate.
"HDB is studying the feasibility of enabling residents to obtain green energy from the vendor directly," a spokesman said. No details are available yet, she added.
Currently, solar panels installed on HDB rooftops in Punggol by leasing company Sunseap generate enough to fully power common area services - such as lifts and lights - in the day; the extra electricity is sold to the grid.
Energy Studies Institute research associate Shiva Susarla said leasing companies would make more profit if they could sell the power to households.