After 18 months, the system was finally hooked up last week.

The 32-panel system is by no means large. But it can still churn out about 30 to 40 kilowatt-hours on a cloudy day – enough to power 770 light bulbs for up to eight hours – and even more when the sun is out.

“I had two criteria for my project. First, it had to create real and tangible change. I didn’t want to just waste my time on something that wouldn’t benefit the community,” the Year 12 pupil, a member of the school’s sustainability club, said. “Second, to commit to a cause greater than one’s own individual wants and needs.”

The idea is to drive more private development of renewable energy installations by speeding up the return on investment, which can often take decades.

The school joined CLP’s HK$5(US$0.65)/kWh feed-in tariff plan. With that, the school expects to rake in HK$50,000 as revenue per year selling to the grid, and will split the profits with its contractor.

Chan admitted there were challenges, not least in getting adults on board for a student-led project. An application to the government’s Environment and Conservation Fund came to nothing. She had to pitch business proposals and vet supplier quotations, while juggling exams and classes.

“People told me things like ‘Don’t expect too much’,” Chan, who wants to study international affairs and climate policy at university, said. “But they were proven wrong on all fronts.”

Eventually, she found contractor EcoSmart, which agreed to fund, finance and maintain the system until the HK$260,000 investment is recouped, in an estimated five years. The company will take an 85 per cent cut of the profit, and the school will get 15 per cent.

ESF – which runs 22 schools – plans to roll out solar panels at its other institutions, with projects in the pipeline at its King George V School and Kowloon Junior School, both in Ho Man Tin.

Greenpeace campaigner Frances Yeung Hoi-shan said the business model was good, but one that only private schools had the luxury of.

“They can do anything, but most public schools or subsidised schools can’t enter into such profit-making deals because of restrictions in education laws,” she said.

She noted that private schools made up a small share of floor area in the city, and if spaces at government schools were freed up there could be a real impact on reducing emissions in Hong Kong.

“Most schools, unfortunately, don’t have the budget to get started, even with the feed-in tariff scheme,” she said.

The pledge to launch feed-in tariffs to help boost the city’s measly renewable energy generation – less than 1 per cent of the electricity mix – was agreed as part of the negotiations for the two power firms’ new 15-year regulatory framework with the government up to 2033.

CLP – which supplies Kowloon, the New Territories and Lantau Island – rolled out its scheme in October. The city’s other power firm, HK Electric – which supplies Hong Kong Island and Lamma Island – began its scheme last month.

For both, the pricing schemes are HK$3 per unit of electricity for systems above 200 kilowatts in capacity but below 1 megawatt, HK$4 for systems between 10kW and 200kW, and HK$5 per unit for those smaller than 10kW.

Acknowledging the high entry costs and red tape most schools face in installing such systems, the Environment Bureau has been devising a new scheme for schools and NGOs, that involves helping them pay the relevant capital costs and installation fees, plus site inspections and technical support.