Sarah M. Jordaan
Energy Technology Innovation Policy Research Group, Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, United States IN Environ. Sci. Technol., 2012, 46 (7), pp 3611–3617
Publication Date (Web): February 24, 2012
Expansion of oil sands development results not only in the release of greenhouse gas emissions, but also impacts land and water resources. Though less discussed internationally due to to their inherently local nature, land and water impacts can be severe. Research in key areas is needed to manage oil sands operations effectively; including improved monitoring of ground and surface water quality. The resulting information gap means that such impacts are not well understood. Improved analyses of oil sands products are required that compare land and water use with other transportation fuel pathways and use a regional perspective so local effects can be considered and mitigated.
Land and Water Impacts of Oil Sands Technologies
1 How Different Are the Impacts of Oil Sands Extraction Technologies?
Bitumen is extracted from the oil sands using two technologies, surface mining or in situ recovery, each of which have different land and water impacts. Surface mining techniques remove shallow depth oil sand deposits by truck and shovel and extract the bitumen with the Clarke hot water extraction process by mixing the oil sand with water warmed using natural gas.(11) In situ technology is predominantly used for extracting deeper deposits. Thermal in situ technologies use natural gas to produce steam that is subsequently injected to reduce the viscosity of the bitumen so that it can be pumped to the surface using production wells. It is understood that oil sands technologies produce 10–20% more greenhouse gases than the average conventional fuel when calculating life cycle emissions from well to wheel,(4) yet much less emphasis has been placed on quantifying water and land impacts.
Land use of surface mining is comprised largely of polygonal features (mine sites, overburden storage, tailing ponds, and end pit lakes). In situ development has a different footprint, mostly defined by linear features that extend across the lease area (networks of seismic lines, access roads, pipelines and well sites).(12, 14)As of 2009, only 600 km2 of land were disturbed by surface mining, accounting for 0.3% of the area where oil sands resources are present, or less than 0.1% of the total land area of Alberta. Eighty percent of the resource is currently expected to be extracted using in situ technologies, affecting approximately 136 000 km2 (97% of the total oil sands area).(13) While natural gas is used in surface mining, in situ recovery can use on the order of four times more than surface mining.(11) The cumulative footprint of the future oil sands operations may extend over approximately the 140 000 km2 during the course of the development, comprising of 20% of Alberta, and even more if the upstream footprint from the infrastructure required for natural gas production is included.(14)
Surface mining results in the conversion of large tracts of land, whereas in situ recovery fragments landscapes, both of which result in ecological impacts. Landscape fragmentation occurs when a landscape is broken up into smaller intact units. There are a wide variety of impacts arising from landscape fragmentation. For example, when large tracts of land are converted or land is fragmented, species migration corridors can be lost affecting species diversity and viability at larger scales. In the boreal forest of Alberta, studies have shown linear disturbance can impact a variety of species populations, from songbirds to carnivores.(15-19) The conventional wisdom is that mining operations have a much larger landscape impact than in situ recovery—the latter has typically been viewed as more environmentally benign in terms of land use.(11, 20)
This conclusion does not reflect landscape fragmentation caused by in situ projects and upstream natural gas production. The land impacts of in situ recovery may be comparable and even greater than that of surface mining when these are considered per unit of synthetic crude oil.(14) To show this, fragmentation was examined through a measure of edge effects, defined as the ecological impacts extending from the juxtaposition of two different landscape types (Figure 1).
Figure 1. Land disturbance and fragmentation from oil sands surface mining and in situ recovery.(14) Edge effects are included as a proxy for habitat fragmentation by applying a parametric buffer to linear features. (a) shows the land occupation without accounting for edge effects, (b) shows the land influenced when considering edge effects that extend 30 m from the disturbance and (c) shows the land influenced when considering edge effects that extend 300 m from the disturbance. The values used in this study were collected based on two focused studies on the land use footprint of oil sands and natural gas in Alberta(12, 21) and were verified with data from GIS analyses(22) and previous studies.(14) (reprinted from ref 14 with permission from IOP Publishing).
Sarah M. Jordaan is a Postdoctoral Fellow at the Energy Technology Innovation Policy research group at Harvard University. A portion of her research has been conducted with the Laboratory on International Law and Regulation at the University of California, San Diego. She earned her PhD in 2009 at the University of Calgary in Environmental Design with the Energy and Environmental Systems Group of ISEEE. Dr. Jordaan’s primary research interests involve systems-level analysis of the environmental impacts of energy technologies. Her research has typically examined the impacts of technologies from a life cycle perspective, with the goal of informing policy and decision-making.
To date, she has been involved with specific projects on oil sands development, shale gas extraction, ethical implications of biofuels, water consumption of alternative transportation fuel scenarios, and the development of quantitative tools for comparing the land use of energy extraction more broadly.