The warning of hefty tariff increases by the city's top energy supplier is a case of déjà vu. After imposing a 5.9 per cent tariff increase early this year, CLP reiterated that electricity prices could rise 40 per cent within a few years, saying the switch to natural gas has pushed up fuel costs. The gloomy picture should not come as a big surprise. The power giant first sounded the warning last year after being forced to cut back its annual increase substantially. The rhetoric is nothing new but it is guaranteed to generate outrage, coming from a monopoly that earned HK$8.3 billion last year.