The SAR's two power utilities - CLP Holdings and Hongkong Electric Holdings - are due today to table their long-awaited tariff plans to the Legislative Council. Customers in Kowloon, the New Territories and Lantau, CLP's service area, are expected to enjoy a one-off cash rebate. However, customers on Hong Kong and Lamma Islands will see bigger bills as Hongkong Electric is expected to raise tariffs by an average 3.5 per cent. Hongkong Electric's plan to raise tariffs is likely to fuel further criticism. A group of six major property developers, hoteliers, retailers and small and medium-sized enterprises recently called for lower tariffs and the revision of the Scheme of Control regulatory mechanism. The power firms will justify their plans today at the economic services panel meeting as a courtesy to the government. CLP and Hongkong Electric can fix tariffs according to their capital expenditure plans under the regulatory mechanism. The scheme stipulates that the power firms can earn a return of between 13.5 per cent and 15 per cent of their average fixed asset value. The agreement aims to balance the interest of the power firms, their shareholders and customers. However, critics said the agreement was effectively a 'build more, charge more and earn more' mechanism. Issues also to be discussed at the panel meeting are the interim review of the Scheme of Control agreement next year, the regulatory regime after the agreement expires in 2008 and the increased interconnection between CLP and Hongkong Electric. The Economic Development and Labour Bureau is to reveal its plans and timetable for next year's interim review and the findings of a study into interconnection.