Roundtable lawmaker Michael Tien described it as "pure luck" that households get to pay less for electricity next year, urging the government to implement measures to stabilise tariffs in the long run.

The city's two power firms, Hongkong Electric and CLP, on Tuesday said electricity charges will go down by 16 percent and 7.4 percent respectively, with a drop in fuel prices offsetting the increase in the basic charge for each unit of electricity people use.

"We may not be that lucky again next year. So, [the authorities] need to set up a separate fund for stabilising the electricity [price] increase during the years where there is a huge jump in oil prices," Tien said.

Meanwhile, chief executive of the World Green Organisation, William Yu, said he welcomes a penalty system in the event of large-scale power outages.

"It's reasonable to introduce this penalty mechanism, especially we see there will be a reduction in their profit return, certain percentage of reduction. So, I think that will actually drive the utilities to maintain high-quality service to ensure there will be no discontinuity in the power supply," he said.

On government plans to introduce more clean energy from the mainland, Friends of the Earth called on the authorities to open up the energy market by introducing new technology and renewable utilities and promoting the long-term development of renewable energy.

The NGO also called on the two power suppliers to fulfil their social responsibility and bear the risk of volatile fossil fuel prices, easing the burden on residents and prompting long-term development of renewable energy.