Water use in oil production
Duane Pendergast, Friday, July 14, 2006
I’ve read a number of articles lately lamenting the rapid development of oil extraction capability from the tar sands in northern Alberta. Much of the concern comes from environmental organizations. An oft repeated point concerns the “huge”or “lavish” amount of water used by the extraction process. The Pembina Institute indicates that 2 to 4.5 litres of water are used to produce a litre of oil from surface mining operations. Developing in-situ extraction processes are projected to use much less at around ¼ litre of fresh water per litre of oil. Pembina Institute and others are very concerned that this is excessive.
At the same time we hear a great deal of environmentally evoked enthusiasm for the development and use of vegetable oils for “biodiesel” fuel. Our local Costco store sells 16 litres of Canola oil for $17. With diesel fuel at about a dollar per litre, how long can it be till we see the Costco parking lot littered with discarded 16 litre plastic jugs? The futures price for soy oil is about 30 cents/lb which is about 60 cents/litre. Canola is similarly priced. At $75 per barrel, crude oil is 36 cents/litre. Since soy and canola meal must also have substantial value it seems that vegetable oil might be close to becoming competitive with crude oil.
Still, I’m leery of the bioenergy boosting we read and hear these days. I’m uncomfortable with the idea we can switch our food production resources to feeding our cars and trucks when so many go hungry in this world. I began to wonder how much of our water resources would be needed to produce a litre of biodiesel fuel.
It didn’t take much searching on the WWW to find appropriate data. Information from tests reported by the Canola Council of Canada indicate that adding 11” of irrigation water to canola crops near Lethbridge increases the seed yield by about 1600 kg/hectare. With the additional information that canola seed yields 35% oil and that the specific gravity of canola oil is 0.92, it can be calculated that 4500 litres of irrigation water is needed to grow an additional litre of canola oil. Similar data from Manitoba yields a water/oil ratio of about 3500.
In conclusion, growing canola as a source of biodiesel fuel in irrigated southern Alberta can use from 1000 to 20,000 times the water needed to produce oil from the northern tar sands.
Engineers abhor mistakes and I thank Clive Schaupmeyer for applying his agricultural knowledge to check my data and calculations.
1. London Free Press, Editorial, “Oil sands rush needs to pause”, July 7, 2006
2. Jeffrey Simpson, Globe and Mail, “Alberta tar sands are soaking up too much water”, July 5, 2006
3. Mary Griffiths et al, Pembina Institute, Troubled Waters, Troubling Trends: Technology and Policy Options to Reduce Water Use in Oil and Oil Sands Development in Alberta, 1st Edition, May 2006, Executive Summary, pp. 1
4. Loc. cit. 3, Main Report, Derived from data from Table 2.5, pp. 62
6. Starner, D.E., A.A. Hamama, and .L. Bhardwaj. 1999. Canola oil yield and quality as affected by production practices in Virginia. p. 254–256. In: J. Janick (ed.), Perspectives on new crops and new uses. ASHS Press, Alexandria, VA.