The week in energy: Dirty oil, clean oil | Financial Times

The week in energy: Dirty oil, clean oil | Financial Times:

All forms of oil production contribute to global warming, but some contribute more than others. Producing, transporting and refining crude oil typically accounts for 15-40 per cent of the total greenhouse gases released by transport fuels, and different reserves can be associated with very different levels of emissions. Heavy crude from Canada’s oil sands is sometimes described as “the dirtiest oil on earth”, in part because of the large volumes of carbon dioxide emitted when it is extracted and processed.

Until now, however, comparisons of different sources of crude have been incomplete, failing to cover much of the world’s oil production and missing important sources of emissions. A new paper from a team led by Mohammad Masnadi of Stanford University, published in the journal Science, fixes those problems, analysing data on almost 9,000 oilfields in 90 countries, accounting for about 98 per cent of global production. By their calculations, Canadian oil is not the highest emitting in the world but only the fourth highest, behind Algeria, Venezuela and Cameroon. The two key factors for emissions are how much energy has to be used to produce the crude, and how much unwanted gas is burnt off in flares. Although extracting the heavy oil of Canada and Venezuela does need a lot of effort — including steam injection to melt the thick, sticky crude — production in countries with high rates of flaring such as Algeria and Iran has emissions that are similar and sometimes even higher.