Green Man's Fuel For Thought

In the US they think that the answer is bio ethanol, made from maize (sweet corn), and this is being marketed heavily, partly to reduce dependence on imported fossil fuels. However it isn't the panacea that some people would like to think. The process of growing the corn involves tillage, which gives CO2 emissions from ploughed soils oxidising, and erosion in the wind or rain. Application of fertilisers, made primarily from gas, a fossil fuel, causes pollution when it runs off into watercourses, making algae grow too much and sometimes when this dies and decays in the stream, it causes fish-kills due to lack of oxygen. The fields do not support much wildlife as the crop is an annual, and a monoculture. They may also have pesticides applied. Due to generous subsidies to grow corn for ethanol, marginal land is being brought into production, further decreasing the areas available for wildlife. Furthermore, the conversion of the cobs into ethanol is power hungry, and the process only generates about 25% more energy than it takes to produce. But subsidies make it economically viable.

A better solution would be to make ethanol from cellulose... wood, fast-growing grasses like miscanthus, hemp, or even mixed natural prairie grass, an ecosystem being lost which has a rich biodiversity, even if sensitively cropped for making cellulose-derived bio ethanol. Even better are vegetable oils, the most efficient way of producing energy for vehicles from crops is 'straight vegetable oil' which is milled and pressed on the farm where it is grown and distributed locally. But we still cannot produce nearly enough plant-based fuel to keep driving the amount we do. The only sustainable solution is to drive less, until a truly sustainable solution is found.

This might include electric cars, IF they are recharged from renewable sources, such as electricity company Good Energy or if you're really keen, your own wind turbine/photovoltaic pannels/micro-hydro system. And how many people have got these? Not many of us! It also probably includes diesel cars running on used, filtered vegetable oil. Bio diesel, which is modified vegetable oil, is more 'carbon intensive' due to the processing, and is therefore less sustainable, but better than using non-renewables. Failing any of this, get a smaller car which uses less fuel per mile, drive efficiently with careful acceleration and braking, tyres pumped up to the correct pressure, windows shut, aircon off, and the bag of tools you don't need to lug around taken out of the boot. All these will help you reduce your driving carbon footprint.

For the latest developments in the science of fuels, and the ever increasing 'green' and sustainability agenda, I read NewScientist magazine. Some of the information for this blog entry was extracted from the 18th August issue. And, yes, although my weekly read has a carbon footprint, I do recycle the magazines by composting them and returning some of their carbon to the soil!

John's 'Green tip of the week' is to pledge to leave the car at home one day a week, and go by public transport, bike, or even walk!