Northstar Energy Corporation Emissions-Reduction Initiatives
In 1998, Northstar Energy Corporation implemented two initiatives to reduce greenhouse gas (GHG) emissions. At their Halkirk Oil Battery, Northstar installed a vapor recovery unit (VRU) to collect solution gas from the facility’s tank farm, and redirected it to a flare. They also added a booster gas compressor to collect solution gas that had previously been flared from the treaters. With this innovation, treater gas is compressed, conserved and sold through the Nova Gas Transmission System. The two actions combined have reduced GHG emissions from the Halkirk site by about three kilotons (kt) per year. Northstar’s actions illustrate simple, cost-effective changes that could be made at other large oil battery facilities. The same technology could likely be used in a variety of similar operations.
The solution gas mixture is composed primarily of methane, a potent GHG. Before the VRU was hooked up, solution gas emissions from Northstar’s Halkirk Oil Battery tank farm had simply been vented to the atmosphere. At an average rate of 750 (0.75×103) cubic metres (m3) per day, large quantities of GHG emissions are released over time. With the new system in place, solution gas is redirected to a flare that reduces methane (CH4) to carbon dioxide (CO2) and steam. CO2 is 21 times less harmful than methane in terms of its global warming potential. In addition to reducing the GHG-related impacts of the gases, the VRU virtually eliminates unpleasant odours. The VRU uses very little power, and Northstar calculated that powering the equipment with electricity further helped to reduce fuel consumption. If it were economical, installing microturbines as opposed to flaring would net even greater emission reductions because of the resulting power production.
In addition to the VRU system, Northstar also installed a booster gas compressor at the battery to reduce GHG emissions from the treaters. Previously, the treater solution gas was directed straight to the flare for burning where the CO2 produced by the high volume of flaring was contributing significantly to the facility