Senior Alberta government cabinet ministers expressed different opinions Monday on what effect carbon capture technology would have on reducing pollution from the oilsands industry in light of internal government documents that call that technology into question.

Previously secret ministerial briefing notes obtained by CBC News under freedom of information legislation said only a small percentage of carbon dioxide released by mining the oilsands can be captured and injected underground for storage.

The briefing notes are based on the findings of a joint Canada-Alberta task force on carbon capture and storage.

"Never has been arguments been made that this was any kind of panacea," Alberta Environment Minister Rob Renner said in response Monday. "There are opportunities for carbon capture and storage in Alberta. Those opportunities lie to some degree in oilsands."

The Alberta government is spending $2 billion to fund the technology.

Carbon capture technology, which proposes to capture CO2 and pump it deep underground instead of releasing it into the atmosphere, has been proposed as a key strategy for reducing the oilsands' effect on climate change.

In a letter touting the benefits of the oilsands to Canada's economy published Monday in the Toronto Star, Premier Ed Stelmach called carbon capture and storage the best way for Canada "to meet its emissions reduction targets."

But Renner said the largest benefit from the technology will be reducing the pollution from coal-fired power plants, not the oilsands.

Alberta Energy Minister Mel Knight defended carbon capture and storage on Monday, saying it will be effective in reducing pollution from the oilsands.

"If you look at the broad spectrum of oilsands over a period of time, we see up to 75 per cent capturable and this is, don't forget also a very long-term project," Knight said.

"We are talking about our time frame out to 2050. In the time between now and then, I'm sure the technology will catch up to many of these issues and we will resolve them."

But Renner wasn't as confident as Knight. He isn't sure how much of the emissions from the oilsands can be captured by this technology.

"That's why we are spending $2 billion to find out," he said.