OTTAWA -- Canada and the United Kingdom have enticed 18 other nations to adopt their mutual goal of weaning themselves off coal-fired power -- but at least two provinces are trying to negotiate their way out of the federal government's own domestic plan.

Environment Minister Catherine McKenna was all smiles Thursday as she and her British counterpart officially launched the Global Alliance to Power Past Coal at the United Nations climate change talks in Germany.

Eighteen countries, five provinces and two states signed onto the Canada-U.K. alliance.

"We're seeing huge momentum for this move away from coal and towards clean power," McKenna said in a conference call after the event in Bonn, Germany.

The world's biggest emitters, like China, the United States and India, were not there. Neither was Germany, one of the world's loudest voices in the climate change battle but whose domestic reliance on coal is still stopping it from promising to phase it out.

The alliance aims to have 50 members by the time the UN climate talks take place in November of next year. Right now McKenna has some work to do getting every Canadian province onside, let alone the rest of the world.

Only four provinces still need coal to make electricity, and McKenna said she is working with Alberta, Saskatchewan, Nova Scotia and New Brunswick to phase it out by 2030, including offering up federal money to help. So far, only Alberta is on board and has a plan to do it.

Saskatchewan Environment Minister Dustin Duncan said Thursday he is negotiating a deal with McKenna to let his province get credit for the carbon capture and storage system it has on one coal-fired power plant to offset the emissions from continuing to use at least one other plant without such a system after 2030.

Duncan said several plants in the province would have to be retrofitted before 2030 to keep them operating, but there is one that won't hit its 50-year lifespan until 2042 and Saskatchewan has no interest in turning it off early.

"We think we're pretty close (to an agreement)," Duncan said. "My expectation is and certainly my interest is that the equivalency agreement, the wording, will be agreed to by the federal minister shortly, in the next couple of weeks."

Saskatchewan currently relies on coal for more than 50 per cent of its electricity. About 25 per cent comes from natural gas power plants and 18 per cent from hydroelectricity and other forms of renewables. The province hopes to get to 50 per cent renewables by 2030.

Conservative environment critic Ed Fast said this week his party believes Canada should eliminate "dirty coal" plants that have no technology to reduce their emissions but it has to be done in a time frame that doesn't hurt either the economy or hike power bills. He pointed to Ontario, where power bills soared 70 per cent as coal plants were phased out between 2006 and 2014, as an example to be avoided.

Keith Stewart, a senior energy strategist at Greenpeace Canada, said Saskatchewan's plan is ridiculous and Canada's international coal phase-out push will be undermined if McKenna allows it.

"That shouldn't even be on the table," Stewart said.

Nova Scotia, which uses coal for almost 60 per cent of its electricity, is also negotiating an equivalency agreement with Ottawa to get credit for cutting emissions elsewhere that would allow it to continue to use coal-power as well. Like Saskatchewan, Nova Scotia anticipates needing coal into the 2040s.

A spokesperson for the New Brunswick government said Thursday that getting rid of its only coal plant by 2030 would be ideal but that will only happen if Canada comes up with "adequate support" to minimize impacts on both power bills and the economy. If not, the province will aim for a coal phase-out by 2040.

About 10 per cent of electricity in Canada now comes from burning coal, half of what it was 15 years ago largely because of Ontario.

Electricity accounted for 84 million tonnes of greenhouse gas emissions in 2015, and coal is responsible for almost three-quarters of that. Eliminating coal and replacing it entirely with non-emitting renewables would get Canada about one-third of the way to its 2030 emissions reduction target.

-- with files from Jennifer Graham in Regina, Kevin Bissett in Fredericton.