HALIFAX -- Nova Scotia will require industrial facilities generating 50,000 tonnes or more of greenhouse gas emissions per year to report emissions under its proposed cap and trade regime, although key details such as the actual caps and their effect on consumers are yet to be released.

Environment Minister Iain Rankin said Friday that regulations are being developed that would make participation mandatory for about 20 large industrial emitters including Nova Scotia Power, Northern Pulp, Lafarge, and large oil and gasoline companies such as ExxonMobil, Imperial and Irving.

"The next round we will have our caps set in place," said Rankin. "We have some discussions we have to do with Environment and Climate Change Canada to know exactly where those caps will be, but the important part of that is that they will be declining caps year over year."

Officials said much of the larger entities' emissions data is readily available because they already report to federal authorities.

Nova Scotia's regulations will also cover petroleum product suppliers that import or produce 200 litres of fuel or more per year for consumption in the province and natural gas distributors whose products produce at least 10,000 tonnes of greenhouse gas emissions a year.

Rankin said companies must report by May 1 this year and by June 1 in subsequent years. They must get their reports verified by a third party by Sept. 1 every year.

The government passed enabling legislation for cap and trade last fall but no information has been released on how much the measure will cost the economy. Premier Stephen McNeil has said the goal is to reduce emissions with minimal impact to consumers.

"We don't have caps yet," Rankin said. "We need to find our baseline, we need to set caps, and then we will be able to have a discussion on what the impact will be."

The caps are expected to be in place sometime this spring.

Nova Scotia opted for cap and trade in November 2016 as part of the federal government's push to get the provinces to set a price on carbon. An agreement recognized the province had already met Canada's target of a 30 per cent reduction in emissions from 2005 by 2030.

The province's legislation has set out that the province is going it alone. McNeil hasn't ruled out some sort of regional arrangement, but Rankin said no other province in Atlantic Canada had approached Nova Scotia about working together.

Jason Hollett, the Environment Department's executive director of climate change, said Nova Scotia's program would cover 80 to 90 per cent of all emissions in the province.

"The other emissions come from things like landfill gas emissions, agriculture tilling -- the release of methane through soil -- those types of emissions are really difficult to measure and calculate, so generally for carbon pricing programs you don't cover those emissions."

The province says its cap and trade program is slated to begin next January.