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Climate change and the NS oil industry Gas-powered facilities on the North Slope emit large amounts of carbon dioxide but reducing these emissions could prove very costly Alan Bailey Petroleum News
Although climate change concerns in Alaska have tended to revolve around impacts such as coastal erosion and melting permafrost, the state administration has also been looking at the other side of the equation: the state’s contribution to world greenhouse gas emissions. And a review of greenhouse gas emissions in the state inevitably ends up looking at the North Slope and the oil industry, the state’s largest industry and operator of fossil-fuel burning industrial plant and machinery.
As part of the preparation of an Alaska climate change strategy for Gov. Palin’s Climate Change Sub-cabinet, an Oil and Gas Working Group is assembling informaation about oil industry greenhouse gas emissions and possible options for reducing those emissions. The working group’s findings will form part of a package of climate change mitigation ideas being assembled by the sub-cabinet’s Mitigation Advisory Group.
In a Feb. 2 session of the Alaska Forum on the Environment, Diane Shellenbaum, a petroleum geophysicist with Alaska’s Division of Oil and Gas and a member of the Oil and Gas Technical Working Group, overviewed data about greenhouse gas emissions from the oil industry and outlined some steps that might be taken to reduce those emissions.
15 million tons Alaska Department of Environmental Conservation data indicate that out of a total of 52 million metric tons of carbon dioxide equivalent emitted in Alaska during 2005, emissions from stationary carbon dioxide sources amounted to 21 million metric tons, with 15 million metric tons of that coming from the oil industry, Shellenbaum said.
The total emissions of 52 million tons from Alaska amounted to about 0.7 percent of the total U.S. emissions, she said.
The majority of the oil industry emissions came from the North Slope. Oil facilities in Cook Inlet also emitted a sizable quantity of carbon dioxide, while some carbon dioxide came from in-state refinery and pipeline operations.
Given that distribution of greenhouse gas generation, the working group has particularly focused on North Slope emissions, although a number of the recommendations might also be applied in areas like Cook Inlet, Shellenbaum said.
Three quarters of the carbon dioxide emitted on the North Slope came from Prudhoe Bay field facilities, with other North Slope oil fields contributing the remaining 25 percent. And an analysis of emissions from Prudhoe Bay indicated that almost all the carbon dioxide originated from the burning of natural gas in the oilfield facilities, Shellenbaum said.
“That controls our focus on what kind of recommendations to emphasize — where can we get the biggest bang for the buck,” Shellenbaum said.
Conservation Fuel conservation and the reduction of waste come at the top of the list of recommendations for the North Slope, Shellenbaum said. That could entail reducing the use of liquid fuels, and perhaps locating and reducing any methane leakages from the oilfield facilities — methane is a more potent greenhouse gas than carbon dioxide.
A second group of greenhouse gas mitigation options would involve improving thermal energy efficiency in the oilfield facilities. It might, for example, be possible to improve power generation efficiency by having centralized power generation on the North Slope, rather than having individual fields generate their own power, Shellenbaum said.
Although technically feasible, this type of arrangement would have to address complications such as the use of gas from one field to provide power for another field. On the other hand upgrading existing equipment could in itself increase energy efficiency, Shellenbaum said.
However, upgrading or modifying the existing plant on the North Slope would cost a considerable amount of money.
“It doesn’t make any economic sense right now to do it … so how can we come up with incentives? How can we come up with a win-win that makes sense for the companies and makes sense for the state too?” Shellenbaum said.
Other options Another approach to reducing carbon dioxide emissions could be the implementation of renewable energy sources to displace the use of some natural gas as a fuel. Possibilities include wind power, or geothermal energy from the hot water that flows from the oil wells, Shellenbaum said.
Greenhouse gas emissions might also be reduced by capturing the carbon dioxide and sequestering it underground, either by extracting the carbon dioxide from the fuel gas or by extracting it from exhaust from the gas-powered equipment. And the economics of sequestration could be improved if the carbon dioxide were used for a productive purpose such as oilfield enhanced oil recovery.
However, although the working group is including potential carbon dioxide sequestration as a recommendation, the technology for implementing this approach is not fully developed, Shellenbaum said.
“We think we can get it to work, but we are on the edge of new technology,” she said. “… It’s not as well understood technology as energy efficiency.”
The upshot of the Oil and Gas Working Group’s analysis is a conclusion that fuel conservation and waste reduction should be the primary short term focus for the reduction of greenhouse gas emissions. In the longer term major modifications to the North Slope infrastructure for improved energy efficiency could have a significant impact on emissions but would require major investment and changes to the regulatory environment.
Possibilities for the use of renewable energy sources on the North Slope should be researched.
However, because the operation of carbon dioxide sequestration would itself use energy, efficiency improvements should be sought in preference to the use of sequestration, Shellenbaum said.
And as a more general approach to reducing greenhouse gas emissions in the more distant future, electrical power could perhaps be exported from the North Slope, with the greenhouse gas emissions captured on site, the Oil and Gas Working Group has conjectured.
But there also needs to be an understanding of the economics of achieving emission reductions, given that a number of the reduction measures would be very costly to implement.
“How can we make this work without destroying our own economy?” Shellenbaum asked. “We want to reduce greenhouse gases as much as possible and we want to do it as efficiently as possible.”
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