Some Nunavut communities could cut their fossil fuel use by up to half with renewable energy that wouldn't cost any more than the aging diesel generators they now use, a new study has concluded.

"The technical challenges have been for the most part addressed," said Claudio Canizares, one of the authors of the report which was funded by the World Wildlife Fund with participation from five Inuit, academic and environmental groups.

The study comes as the federal and territorial governments consider what to do about 300 mostly northern communities that rely on diesel to generate electricity.

Many are aging and long past due for replacement. In Nunavut, 13 of the territory's 17 generators are more than 35 years old. All are expensive to run and they emit greenhouses gases and black carbon, which contributes to melting of sea ice.

A 2015 Senate report found northern electricity systems are "aging, underperforming and at capacity." Nunavut has asked Ottawa for $250 million to replace and upgrade the territory's power plants and energy infrastructure.

Canizares concedes that replacing diesel entirely would be too costly. Instead, his report asks which communities would benefit most from using already-proven wind and solar technologies -- without raising costs.

It found in at least five Nunavut communities -- including the capital of Iqaluit -- the current generation of wind and solar systems could replace at least one-third of diesel consumption for the same price as operating and maintaining its old generator.

"Some of these generators are getting old and need to be replaced," Canizares said. "Why not look at renewables?"

The Nunavut government is interested.

"The (territory) is supportive of alternative energy research and implementation," said cabinet spokeswoman Yasmina Pepa. "It would welcome green energy investments."

Renewable energy is spreading in the Arctic.

Colville Lake, high in a corner of the Northwest Territories, has successfully tested batteries and solar panels that should allow the community to run entirely on the sun's energy during summer.

In Nunavik, Que., a wind turbine installed at the Raglan Mine has offset the use of 3.3. million litres of diesel fuel in its first 18 months.

The state of Alaska's US$50-million a year renewable-energy fund has spent some $271 million since 2008 while tracking the annual offsets of diesel fuel use. It reports saving about 75 million litres of diesel fuel in 2015, up from 57 million litres in 2014.

The figures prove that renewables can work in the isolated and harsh conditions of the North, said Canizares.

"Alaska is the example to follow."

The most recent federal budget committed $10.7 million over two years specifically for renewable energy projects in indigenous and northern communities that are off the grid and reliant on diesel power. That's in addition to a $2.2-billion, five-year green infrastructure fund for First Nations communities.

As well, the Vancouver Declaration on climate change signed last fall by all premiers and Prime Minister Justin Trudeau promised early action on "clean energy solutions to help get indigenous, remote and northern communities off diesel."