HALIFAX -- Power rates in Nova Scotia will likely rise incrementally in the future but there will be no wild price swings under a newly released electricity plan, says the province's energy minister.

Michel Samson announced the Liberal government's new 25-year-plan for the province's energy future Monday, saying it would help stabilize rates for residential and business users.

Under the plan, Nova Scotia Power will have until April 30 to set its rate for non-fuel costs for a stability period that will run from 2017 to 2019. The rate will be locked in over that period.

The utility will also have to file a plan dealing with the volatility of fuel costs.

Samson said electrical bills would likely still increase because it is impossible to predict the cost of coal and oil. However, he said the overall result will be more predictable costs for consumers.

"We do expect that Nova Scotia Power will be doing everything in its ability to be keeping those fuel purchases flat or at minimal increases during that period," said Samson.

The plan points out that coal costs have levelled off after a decade during which prices rose as much as 70 per cent. It said that access to long-term renewable sources such as Muskrat Falls power from Labrador also serve to position the province for cost stability.

Nova Scotia Power would also have to meet performance standards set by the Utility and Review Board under the plan.

Samson said the standards would be based on best practices in other jurisdictions, adding that failure to meet them could mean penalties of up to $1 million a year.

"That million dollars will be paid by shareholders, not by ratepayers," he said.

Samson said the money from any penalty would be put towards Nova Scotia Power's fuel costs with the savings passed on to ratepayers.

Nova Scotia Power spokeswoman Sasha Irving said the utility would reveal whether it plans to ask for a general rate increase in 2016 during a news conference on Tuesday.

However, Irving said the timing is right to be looking at a period of rate stability.

"There is certainly more work to be done and we have to ensure we can manage our costs within the time frame that the plan outlines," said Irving.

The plan also commits $1.5 million over the next three years to support pilot projects and research related to electricity use.

New draft rules are being developed to open the retail market and allow smaller independent power producers to sell directly to customers. Those regulations are expected to take effect in 2016.

Progressive Conservative Leader Jaime Baillie panned the plan for power rates, calling it a shell game that doesn't go far enough to reel in costs.

He said what's needed is a rate freeze.

"When does stability stop meaning go up again?" said Baillie.

Samson said the government would introduce legislative amendments during the fall sitting of the legislature to support the changes.