Examples of emerging oil sands related technologies and trade-offs. Credit: ACS, Bergerson and Keith. Click to enlarge.

Although it is technically possible to make deep reductions

in oil sands well-to-tank greenhouse gas emissions through the use of technologies such as carbon capture and storage (CCS) and the co-firing of biomass with fossil fuels for process heat or hydrogen, it is unclear if such a strategy

makes sense, Joule Bergerson and David Keith at the University of Calgary suggest in a paper published online 12 August in the ACS journal Environmental Science & Technology.

The paper is an examination of how various choices about the

scale of the life cycle analysis applied to oil sands (i.e., system boundaries) determine the emissions estimates, the technologies available to reduce

emissions, and perspectives and strategies of stakeholders. Bergerson and Keith pay particular attention to CCS, showing how divergent views about its cost effectiveness emerge from divergent choices about the scale of analysis.

“Debate about the future of oil sands development is so

contentious that even the name of the resource is disputed:

proponents typically use oil sands while opponents use tar

sands. We use oil sands not to express our views on the debate,

but because tar is technically incorrect because tars are

products of biomass combustion and are chemically distinct

from bitumen. The source material is neither oil nor tar but

bitumen, but is most generally described as an example of

ultraheavy oil.”

—Bergerson and Keith

The authors note that while some sources claim that the oil sands are up to 5 times more emissions intensive than conventional oil, others claim that they are as low as 10% more intensive. Both those claims can be defended, with the discrepancies arising “from an artful choice of the scale of analysis.”

The core of the discrepancy is whether or not the energy intensity and GHG

emissions are measured from the well-to-tank (WTT) or over

the full life cycle (well-to-wheels [WTW], from extraction of

the resource through to the use of the fuel in a vehicle). About 60-80% of full life cycle emissions result from driving/operating a vehicle; if only the extraction

emissions (WTT) are examined, oil sands will deliver a relatively high value.

A recent study by Bergerson and Keith’s group at the university (Charpentier 2009) reviewed published literature and concluded that while the extraction energy intensity and GHG emissions associated with oil sands are typically higher than those of conventional production, “it is not inconceivable that an oil sands pathway

may perform better than a conventional oil pathway, under

certain circumstances”.

They also note that if the scale of analysis is that of the entire economy, the

value commonly referenced for economy wide emissions is

that oil sands constitute ~5% of Canada’s emissions. However, this only

accounts for the processing that occurs in Canada and

therefore excludes much of the refining and transport

emissions. Nor does this estimate include the use of

transportation fuels in vehicles, which occurs throughout

North America (NA); approximately two-thirds of oil sands

products end up in the US. All told, they wrote, the well-to-wheel (WTW) emissions

of oil sands products constitute roughly 2% of total emissions

in Canada and the US.

While oil sands emissions have more than doubled from 1990 to 2006, the absolute increase in emissions from oil sands over the same period is less than the absolute increase in Canadian electric or transportation sector emissions, and far less than

the increases in these sectors on a North American basis, they note.

Furthermore, they write, if the relative cost of cutting emissions was high

in a given sector, then growing emissions alone would not

solely justify major focus on cutting in that sector alone. In

Alberta, for example, CO2 emissions from coal-fired electric

power exceed emissions from oil sands and the costs of

reducing emissions from coal electricity are lower. Yet, coal-fired

emissions in Alberta receive relatively little attention

from environmental organizations and the public.

In addition, oil sands are a nearly unique emissions source in the global energy system; investments (money and political capital) in stopping oil sands emissions cannot easily be transferred to stopping emissions elsewhere, unlike technologies to reduce emissions from coal-fired power.

Why then the focus on oil sands? One reason it makes

strategic sense to focus on oil sands is that they represent

the world’s first major step into extra-heavy unconventional

oil. Without strong climate policy, one might expect production

of unconventional hydrocarbon fuels to increase dramatically

in the coming decades as supplies of conventional

oil become gradually tighter. A growing supply of unconventional

transportation fuels would tend to moderate oil

prices and would drive up emissions on a life cycle basis.

Moreover, slowing or halting the development of oil sands

and similar unconventional fuels such as coal-to-liquids will

tend to push up prices for fossil transportation fuels easing

the introduction of alternatives such as electric vehicles or

biofuels. There is, therefore, a sensible strategic reason for

ENGO’s to devote substantial efforts to stopping the development

of oil sands, efforts that are not directly related to

their current environmental impact.

…The cost of reducing these emissions will be

high compared to emissions reductions achieved elsewhere

in the economy. The environmental impacts of CO2 emissions

are the same wherever they occur, so seen through the lens of

environmental cost-benefit analysis it makes little sense to

devote major resources to reducing oil sands process emissions.

Resources might be better spent on the long-run task of

developing technologies that can decarbonize the transportation

sector by moving it away from oil as a primary fuel.

We hope that developing better public domain life cycle analysis

of the technical potential, costs, and environmental impacts of

oil sands technologies along with transparent methods to

describe the trade-offs involved in decarbonizing the transportation

sector will help clarify the messy interaction of strategic

interests and contradictory claims at play in the oil sands debate,

increasing the chance of choosing an economically sound path

to a carbon-neutral future.

—Bergerson and Keith