SAGD projects graded on environmental impact

VANCOUVER — Oilsands companies in Alberta using in situ, steam-assisted gravity drainage (SAGD) extraction techniques on deposits too deep to mine will no doubt end up doing less environmental damage than comparable open-pit oilsands operations.

And SAGD operations are sure to increase. In 2008, roughly 55% of production from Alberta’s oilsands was from mining, but 80% of the estimated reamining 175 billion barrels of crude bitumen buried in the province is too deep for mining.

The less-invasive SAGD technique involves installing pipes underground through which steam is pumped to both liquefy the thick bitumen and force it to surface.

SAGD often uses much less water than oilsands mining operations, especially because it generally doesn’t use fresh water from the Athabasca River. Other comparable benefits of SAGD are that it disturbs much less land and doesn’t require tailings pond. The ponds, which in 2009 spanned 130 sq. km and contained 720 billion litres of waste, have been the most visual reminders of the oilsands’ environmental degradation.

But a recent round-up of SAGD projects by the Pembina Institute, a Calgary-based environmental non-governmental organization, finds that SAGD has much higher carbon and related emissions than oilsands mines because of the intense energy required to pump large volumes of high-pressure steam underground.

Out of the nine Alberta projects Pembina compared, SAGD operations produce on average 2.5 times more carbon and related emissions per barrel of bitumen than mining operations.

Mining operations also produce, on average, 30% lower sulphur emissions than SAGD.

According to Pembina’s ranking, its top environmental performer is Suncor Energy’s (SU-T, SU-N) Fire-bag project while the worst is Canadian Natural Resource’s (CNQ-T, CNQ-N) Primrose/Wolf Lake project.

As for other emissions, such as nitrogen oxide, nitrogen dioxide and sulphur dioxide, Suncor was the only one to have committed to reducing absolute emissions, by 10% by 2015.

Water use ranged extensively in the nine projects, from 0.4 barrel of water per barrel of bitumen to as much as 6 barrels of water per barrel bitumen. The average was 1.1 barrel, about half the amount needed for mining operations.

Waste water produced per barrel bitumen varied from 0.005 to as much as 4.5 barrels. Many SAGD operations have water recycling infrastructure in place, which significantly reduces both water use and waste water produced, while some operations included in the study have since installed recycling capacity.

The biggest reductions in carbon and related emissions came from improved steam-to-oil ratios, which depend on a number of factors. The steam-to-oil ratio also affects water use, and sulfur-dioxide and nitrogen-oxide levels.

The projects included in the study are Cenovus Energy’s (CVE-T, CVE-N) Foster Creek and Christina Lake, Imperial Oil’s (IMO-T. IMO-N) Cold Lake, JACOS’ Hangingstone, Husky Energy’s (HSE-T) Tucker, Royal Dutch Shell’s (RDS-N, RDS-L) Peace River, Canadian Natural Resource’s Primrose-Wolf Lake, and Suncor Energy’s Firebag and MacKay River. The study used data from 2007.