Mason says profits of power generators in Alberta rose as much as 25 per cent between the third quarter of 2010 and the same time in 2011.
He says an NDP government would freeze power prices at a fair, affordable level and then require power companies to justify rate increases before a utility board.
The NDP said last week that it's launching a petition to tap public discontent over high electricity prices.
Mason said the idea came after scores of people contacted the party to complain about high power prices.
Anyone in Alberta not on a fixed-rate contracts will pay a record 15 cents a kilowatt hour this month — double what was charged last January.