The allure of uncorny ethanol

Iogen 1

 

Henry Ford had it right: ethanol is a better fuel to use for cars and trucks than gasoline.

It has an octane rating that’s 15 per cent higher, which means you don’t have to use additives to prevent knocking or to improve combustion.

It has a lower vapour pressure than gasoline, which is a great advantage because 40 per cent of car emissions is caused by evaporation.

And its makeup is far less complex than gasoline, so it is much easier to fine tune an engine to utilize every last drop of energy — which helps offset the advantage gasoline has in containing 50 per cent more energy than ethanol.

What Ford had no inkling of, back in the 1920s, was that gasoline is brutal to the environment, and ethanol is not — assuming the ethanol is made from cellulose, in other words, from grasses such as timothy or switchgrass, or from agricultural waste such as wheat, oat, or barley straw, or from corn stover (stalks and cobs stripped of corn).

Ethanol lost out to gasoline because, in the 1920s, Prohibition was in effect, and U.S. authorities were worried that ethanol manufactured for cars might end up in martini glasses instead of in gas tanks. Also, since the ethanol would have been made from corn, there was concern that corn growers might co-opt land needed for growing grain.

Even today, however, switching cars to ethanol made from corn kernels has its problems. When you do a life cycle analysis of corn-based ethanol — and add to engine emissions the greenhouse gas emissions that result from manufacturing and delivering the pesticides and chemical fertilizers that corn growers use, plus the emissions from farm machinery, plus the emissions related to manufacturing the ethanol — the total greenhouse gas load is substantial.

But ethanol from grasses and agricultural waste is a totally different proposition. Its life-cycle addition of greenhouse gases to the atmosphere can be astonishingly low — as minute as 15.4 grams per litre of equivalent carbon dioxide (CO2), compared to 3,135.5 grams per litre of equivalent CO2 for gasoline. In other words, 204-times lower than gasoline.

That’s the target set by Iogen Corp. of Ottawa, and its partner PetroCanada. The two will open Canada’s first ethanol-from-cellulose plant in August at a cost of $25 million. It will produce 4 million litres of ethanol a year. Iogen’s expertise in tailoring enzymes for industrial processes will go into manufacturing the ethanol; PetroCan’s expertise in marketing will go into selling it.

Here’s how the life-cycle analysis of the ethanol’s greenhouse gas impact is calculated, and I’ll use switchgrass as an example of the feedstock. Switchgrass is a perennial, so every year it takes enough carbon dioxide out of the air to build its stalks.

Making ethanol is a process of transferring carbon from the stalks to the ethanol. When the ethanol is burned, the carbon is emitted primarily as CO2. It will be the same amount as was in the stalks. So when the switchgrass grows again, it will take out of the air the same quantity of CO2 as was emitted. The net addition of CO2 to the atmosphere will be zero.

In the manufacturing process, Iogen will remove lignin from the stalks and burn it to create electricity. Lignin is the material that makes the stalks stiff, able to stand up and resist the wind.

Once again the net addition of CO2 to the atmosphere will be zero, because the new crop of switchgrass will absorb the same amount of CO2 as was stored in the lignin.

Like hay, switchgrass requires low maintenance, so the farmer’s net addition of CO2 will be low, especially if his equipment runs on ethanol. And if PetroCan’s delivery trucks run on ethanol, there’ll be zero addition there, also.

And I’ve saved the best until last. What happens if there’s a spill? As one American writer put it: « If a second Exxon Valdez filled with ethanol ran aground off Alaska, it would (only) produce a lot of evaporation and some drunk seals.’’

 

NEXT WEEK: Flexible fuel cars

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