The city's largest electricity supplier has been criticised for double standards in setting tariffs after Greenpeace found a significant rise in residential charges but a small reduction in commercial tariffs since 2004. CLP Power, which supplies more than two million users in Kowloon, Lantau and the New Territories, adopts different tariff structures for the two sectors. While households consuming more energy have to pay a higher unit price, large commercial users are actually paying a lower rate than smaller consumers. "The regressive tariff structure for commercial users does not encourage energy saving. It should be overhauled when the regulatory framework is reviewed in 2018," said Greenpeace campaigner Argo Yeung Man-yau, who compared the existing price with that of a decade ago. His remarks came with the government expected to gauge public views on ways to reform the electricity market early next year. According to Yeung's analysis, households consuming more than 4,200 kilowatts per hour - the biggest users under the domestic tariff structure - are being charged at HK$1.73 per unit this year, a 60 per cent rise from HK$1.079 in 2004. Those consuming less than 400 kilowatts per hour are being charged HK$0.817 per unit this year - a 4.8 per cent cut from HK$0.857 a decade ago. As for the commercial sector, their biggest consumers such as public utilities and infrastructure companies are paying HK$0.431 this year - 0.6 per cent down from HK$0.434 in 2004. Small to medium businesses are paying 1.5 per cent more, from HK$0.968 in 2004 to HK$0.982 this year. "That means a shopping mall is paying a cheaper rate than a small restaurant. It's unfair," Yeung said. A CLP Power spokeswoman said applying increased tariffs to the largest users, such as schools, hospitals and public utilities, would increase the social cost of providing a wide range of services to the community.