Friday, February 6, 2009

Dirty Fuels

There is an interesting article recently in Environmental Research Letters (ERL) concerning the greenhouse gas emissions in producing oil from tar sands.

For a brief introduction, tar sands are bitumen, a tar-like petroleum substance, trapped in a matrix of sand and rock. There are two processes used to obtain the bitumen. About 70% of the tar sands are first open-pit mined and then placed in ponds. Hot water is added to the ponds and the bitumen floats to the surface. The bitumen is then removed and processed to create a synthetic crude oil. The remaining 30% of tar sands are processed by introducing steam into the ground and then the water and bitumen are pumped out again into ponds.

The result of the ERL review article shows that the amount of greenhouse gases released to produce the synthetic crude oil is higher than that for conventional oil production.

The results are not surprising. The problem is that to remove the bitumen and then further process it requires energy.

There are other problem also with tar sands. They are high in sulfur and the hot water processing releases highly toxic hydrogen sulfide. This has caused problems previously.
And then there is the threat to wildlife (in addition to the mining itself). Last year in Canada (where most of the commercial tar sand operations exist) 500 ducks landed on one of the ponds described above. All but five died. In addition the incident was found out by a tip-off, not under the companies reporting requirements as required by the Canadian government.

Oil shale is in some ways similar, but worse. Oil shale is a rock which contains a mixture of organic compounds called kerogen (despite its name it does not contain oil). In order to get a petroleum product the rock needs to be crushed and then heated to a very high temperature, which of course requires a large amount of energy. This energy is substantial, it is nearly the energy value of the resulting "shale oil".

Coal liquefaction technology converts coal to a liquid fuel (the specific fuel depends on the process used). Here we must add energy to this conversion. Again it has been shown that the greenhouse gases produced exceed that from direct combustion of the coal. I will say it again, there is no such thing as "clean coal"

Yet these technologies -- tar sands, oil shale, coal liquefaction -- have all been pushed by the energy companies. Yes, some energy companies are looking into hydrogen and other alternative energy sources, yet they are for "unconventional oil" and against measures to reduce global warming (see previous blog).

I believe that the energy companies are really not wanting to get left behind in the race to develop new energy markets. But they do not want anything which will reduce peoples need for energy, since they are in the business of selling energy resources.