Canada released long-awaited regulations Friday that analysts said could phase out most of the country's coal by midcentury.

The new rules apply a stringent performance standard on new plants, requiring them to emit roughly the same greenhouse gases as natural gas generators. That means that new coal plants won't be able to be built in Canada without carbon capture technology, since coal typically releases twice as much carbon dioxide as natural gas does in the burning process.

Considering that carbon capture has never been proven at commercial scale to control coal's emissions, the fate of the fuel in Canada is uncertain.

At a ceremony in Saskatchewan, Environment Minister Peter Kent said the regulations would help Canada meet its goal of slashing emissions 17 percent below 2005 levels by 2020. Coal currently fires about 17 percent of Canada's electricity and releases about 13 percent of the country's greenhouse gases.

"Our government understands Canadians' concerns around the quality of the air we breathe. We know reducing air pollution and greenhouse gases will help us get there," Kent said.

Specifically, the rules require new coal units annually to emit 375 metric tons of carbon dioxide per gigawatt of produced electricity. The only way a coal plant could achieve that level of emissions reduction is with yet-to-be-commercialized technology, analysts said. The rules apply to plants commissioned after July 2015.

But many environmentalists slammed the regulations as too weak. They would not do much to help Canada meet its 2020 emissions targets, considering that the plan applies to new units, green groups said.

The timetable would leave the majority of the nation's coal plants in operation well past 2020, said Tim Weis, an analyst at the Pembina Institute, an environmental think tank. He called the announcement "a positive step forward," but one that would do little initially for climate change.

"Old plants still get to keep going through the end of their design life," he said.

About two-thirds of current plants would not have to meet the standard until after 2020, and nine would operate past 2030 without constraint, Pembina said.

Canada's carbon capture industry applauds

Environmentalists also criticized the government for allowing Maxim Power to move forward with plans to build a 500-megawatt coal plant before 2015, when the regulations would take effect.

"They can't comply with the regulations, so they are trying to get this in before the deadline," Weis said. The matter is tied up in a legal battle, so the "race is on" to see whether the plant gets built, he said.

"Issues remain to be resolved" with the regulations, including the permitting process for transmission lines, said Tracy Walden, a communications manager at the Canadian Electricity Association.

The carbon capture industry in Canada, which has announced some large test projects of late, welcomed the announcement as a big boost.

"This is great news for the carbon capture and storage (CCS) industry because it eliminates regulatory uncertainty in Canada," said Carmen Dybwad, CEO of IPAC-CO2 Research Inc., in a statement.

Kent made the announcement on the grounds of SaskPower, which is planning to retrofit a 100-megawatt coal plant with carbon capture technology. The captured CO2 would be used for enhanced oil recovery, where CO2 is injected underground to extract more crude, keeping it permanently from the atmosphere.

Royal Dutch Shell PLC also signed a deal with the Canadian government this summer to test capture technology on oil sands refineries, the first of its kind (ClimateWire, June 27).

Weis was skeptical that the new regulations would do much to help carbon capture, however. It is more likely that the country will turn to natural gas, he said. With new finds of natural gas, carbon capture will likely be less cost-effective than simply switching generators to another fuel, he said.

"I'm glad to see something done," he said. "But in some ways, this is close to business as usual."