The Liberal government's long-term energy plan ignores its own climate change laws, and more must be done to shift the province from fossil fuels to low-carbon power sources, Ontario's environmental watchdog said in a report released Tuesday.

Environmental Commissioner Dianne Saxe said Ontario's climate laws would require a drop in fossil fuel use by 40 to 50 per cent in the next 13 years to meet emission-reduction targets set for 2030. The target -- a 37 per cent cut below 1990 levels -- is still within reach, but only if the government begins to plan for it now, she said.

"The whole reason to have a 25 to 30-year long-term energy plan is precisely so we can look ahead and make plans and not constantly be panicking and rushing to deal with the latest emergency," Saxe said. "Yet there's nothing in the long-term energy plan to deal with that long-term challenge."

Saxe, a non-partisan officer of the legislature, said the province's long-term energy plan predicts stable demand for electricity but doesn't spell out how it will reduce fossil fuel use. In order to meet its climate change goals, the province will need to shift away from fossil fuel use in some cars and trucks, and from home heating using fossil fuels to electricity.

"Conservation absolutely has to be number one," said Saxe. "It's always the cheapest and the best. But it's not going to take us the whole way ... We're going to need a lot more low-carbon electricity."

In its long-term plan released last fall, the government addressed rising costs in the system and said that for most of the next two decades it aims to keep hydro price increases gradual for consumers, rather than lower or freeze rates.

Average hydro bills are projected to rise to $197 in 2032. That's a slower progression than the government's previous long-term plan in 2013, which expected bills to hit that mark by 2026. But much of that is due to the 25 per cent rate cut introduced by the Liberal government in early 2017 to quell anger around high electricity prices. That move involved a complex borrowing scheme that will cost Ontarians billions in extra interest.

Saxe said the money allocated to lower rates for customers would in some cases be better spent helping low-income residents increase the energy efficiency of their homes.

"If you spend a chunk of money making those homes more efficient, then you do a number of things," she said. "You improve the quality of life for the people living there ... and you reduce their bills."

Saxe also praised the government's role in cleaning up Ontario's electricity system by ending coal-fired power, but the report acknowledges that it has resulted increased costs for ratepayers. The move away from coal-fired power has also helped reduce the number of smog days every year and the health impacts associated with air pollution, she said.

"Another really important thing that people forget that we get with these higher electricity bills is air we can breath," she said. "The sky is blue, not yellow. ... burning coal looks cheap on the power bill but it only looks cheap because you're not counting most of the damage."

Energy Minister Glenn Thibeault said in a statement that the government remains committed to an electricity system that "includes renewable energy generation and conservation" that align with its climate change goals.

Thibeault said funds raised from the province's cap-and-trade plan are being invested in projects that help fight climate change.

"These investments include hundreds of thousands of dollars into transit, and energy efficient upgrades for homes, schools, hospitals, social housing, universities and colleges -- and we will ensure we continue making positive changes to meet and beat our emission reduction targets," he said.

NDP energy critic Peter Tabuns said the commissioner's report points out the "hypocrisy" of the government's energy and climate change policies. The government isn't doing enough to invest in conservation that would drive down costs for the province and ratepayers, he said.

"I listen to the Liberals regularly talk about how climate change is one the greatest issues facing humanity," he said. "And yet when it comes to their own energy plan, they ignore it."