Using solvents in the oilsandsThe good, the bad and the ugly

Blog - May 25, 2017 - By Benjamin Israel

Innovations to reduce greenhouse emissions from the oilsands industry have been long awaited, since bitumen is among the most carbon-intensive oil being produced globally. Injecting solvents such as butane instead of steam underground to recover bitumen in situ is often framed as a way to reduce the high per-barrel production emissions from the oilsands. Wide adoption of these new extraction technologies could allow oilsands production to keep growing while keeping emissions under the legislated 100 megatonne per year limit. But while solvent-based technologies appear to have the potential to reduce the carbon footprint of oilsands facilities that use them, there are uncertainties with the technology and gaps in rules guiding the practice.

The good

Two major potential benefits of solvent-based technologies are the reduction in greenhouse gas emissions coupled with significant decreases in operating costs compared to the current extraction technique, namely steam-assisted gravity drainage (SAGD). Currently, natural gas is used to produce steam, which is then injected into the ground to liquefy bitumen oil enough to bring it to the surface. Between 2014 and 2030, GHG emissions from this SAGD in situ method are expected to increase 300 per cent. However, if instead of superheated steam, light hydrocarbon solvents are injected to liquefy underground bitumen, reductions in GHGs and costs at in situ operations could be significant. A Canadian Energy Research Institute report estimates these reductions can reach 83 per cent for emissions, 40 per cent for capital costs, and 14 per cent for supply costs compared to the incumbent technology. One key driver for these benefits is the reduction of steam use, the generation of which typically bumps up the extraction energy intensity, while use of boilers to create the steam is a significant cost for the facility.

Cost of bitumen production graph

The bad

We need technologies that reduce industrial oilsands emissions, but we can’t compromise on the other environmental impacts of such technologies. Current oilsands developments have a tremendous cumulative impact on land use, air quality, water and wildlife. The effects of solvent-based bitumen extraction won’t be broadly understood until the technology is used on a commercial scale.

The Alberta Energy Regulator has already approved a number of experimental and pilot projects for solvent injection and the Climate Change and the Emissions Management Corporation has provided funding to solvent-based pilots. Despite the support already committed by the Alberta government to this technology, there is a surprising lack of public information regarding the potential impacts that could arise with full-scale deployment of these technologies.

One lingering concern is the potential for surface or subsurface contamination from the injected solvent. Solvent-assisted techniques leave residual solvent underground after bitumen is extracted (between 30 per cent and 50 per cent in the case of Imperial Oil’s technology tested at Cold Lake). While an operation is productive, the subsurface is monitored and the operation is designed to detect any foreseeable solvent loss. How solvent loss is mitigated after detection is not well understood. Furthermore, after production ceases, there is still a risk of solvent leakage, which could contaminate subsurface zones or, in the extreme, release the solvent to surface. This issue is particularly important to those living in the Lower Athabasca Region, where the liability of tailings production steadily increases as projects are developed without proper mitigation measures. Taking on further liability from the potential solvent contamination from these operations is likely unpalatable given the history in this region.

The ugly

The oilsands industry has a long history of broken promises when it comes to mitigating its impact on the landscape. This has resulted in environmental damage and a financial burden on Alberta taxpayers to clean up the mess. Therefore, industry should expect public scrutiny of new technologies.

We have seen what can happen when governments do not proactively address development risks. The unbridled expansion of the oilsands sector in the past illustrates the worst-case scenario. If solvent injection is truly the next generation of oilsands production, then rules guiding site selection, resource characterization, operating parameters, and closure and abandonment requirements need to be established early. This will provide greater public assurance that the potential for unanticipated environmental impacts from solvent-based extraction technologies has been minimized or eliminated.

If the oilsands industry is to survive in a low-carbon world it must significantly reduce its carbon intensity and operating costs. Solvent-based technologies may have merit in this context. But in adopting it, let’s make sure we don’t compromise other facets of the environment in the interest of greenhouse gas emission reductions.

Benjamin Israel

Benjamin Israël is an analyst with the Pembina Institute. He is based in Calgary.


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