Solar panels could soon be seen in army camps, schools and more Housing Board blocks.
The HDB will call a tender next year for such technology. Possible government agencies which may take part are the Ministry of Defence (Mindef) and the Ministry of Education (MOE).
It will be the first tender to aggregate demand across government agencies for solar photovoltaic panels, which convert sunlight to electricity.
Mindef is looking at installing them on the rooftops of camps, while MOE might use them on the rooftops of schools, National Development Minister Khaw Boon Wan said in a blog post yesterday.
HDB's bulk tenders mean several government agencies can benefit from lower costs.
Mr Khaw said HDB is taking the lead in the tender because it has the greatest experience in installing solar panels here.
There are now 176 HDB blocks with solar panels; the figure will rise to 300 next year. They help to power lifts and corridor lighting, at a time when town councils are being hit by rising energy costs.
In March, the Government said it wanted to raise adoption of solar energy to 350 megawatts-peak (MWp) by 2020, or about 5 per cent of annual electricity demand.
Mr Khaw noted that HDB will contribute 220MWp, with solar panels at 5,500 HDB blocks.
"This could generate enough electricity to provide for common services and households in a town the size of Woodlands," he said.
Energy experts supported the move. "We should deploy solar panels wherever there's an opportunity," said Professor Subodh Mhaisalkar, executive director of Nanyang Technological University's Energy Research Institute.
With the cost of solar power falling and the efficiency of such technologies rising, the option makes economic sense, he added.
Sustainable Energy Association of Singapore chairman Edwin Khew said: "As long as the roofs are strong enough to accept the solar panels and the supports needed, it makes perfect sense."
Placing solar panels on land - as is done elsewhere - is straightforward, but roof-mounted solar panels could become "an area of specialisation" for Singapore, he added. "We could take the lead."