SaskPower expects its electricity rates could more than double in the next decade, according to a document released by the New Democrats.

The government hired the polling firm Angus Reid to conduct an online survey that dealt with the future of energy generation, and the document was obtained by the Opposition, the NDP said.

The survey says an annual rate increase of eight per cent for the next decade would be required "to maintain the financial health of SaskPower and ensure a safe, reliable and sustainable power supply for the province."

When compounded, a decade's worth of eight per cent increases results in a total increase of about 116 per cent.

NDP MLA Trent Wotherspoon said the document suggests SaskPower has already decided it wants to raise rates by that much.

That's "shocking" considering that a legislative committee is about to begin a series of hearings dealing with the future of energy generation in the province, he said.

SaskPower spokesman James Parker confirmed the information in the survey is legitimate.

However, he also said the projection of average annual increases of eight per cent is simply a "snapshot" in time and the numbers could change.