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Last week we established that the so called green car is a myth; cars are inherently harmful to the environment. Despite this, most of us would like to carry on using our cars because; let’s face it, they are really convenient. Those of us lacking the environmental zeal to give up the mixed blessing of the automobile are left to seek an alternative to the current expensive black stuff that has us hooked. What are the options for a recovering oilaholic? Well this week I’m going take a rather critical look at the five most talked about options to see, blind optimism aside, whether our love of cars has any hope to continue. The main factors we will look at are efficiency, impact, viability and availability. In this post we’ll look at the two big Biofuels before covering hydrogen, compressed air and battery power later in the week.

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Biodiesel
At least initially, Biodiesel seems like a pretty good option to replace traditional oil. Biodiesel uses fats or vegetable oils and other ingredients to create a replacement for conventional oil derived diesel (petrodiesel). According to Wikipedia, this replacement functions in much the same way as petrodiesel but can substantially reduce green house emissions (other than nitrogen oxide), especially when a mix of the two fuels is used. The fuel is biodegradable, non-toxic to humans and can be used in conventional diesel engines. The fuel can even be recycled from used vegetable oil that would otherwise be discarded from restaurants, though if adopted widely demand would far exceed supply.
Biodiesel is not without its critics however, even within environmental spheres. The ease at which Biodiesel can be produced at home has been greatly exaggerated, with significant safety and cost issues to be done well. The production of palm oil crops for the fuel has already resulted in widespread deforestation in the Philippians and Indonesia, threatening natural wildlife and resulting in more CO2 from the burning of the rainforests. As it is based on crops, Biodiesel production can have a significant impact on food prices which is a significant humanitarian issue. Several University studies have concluded that the energy and pollution payback from crop-produced is poor and the process is not sustainable. While the end product of Biodiesel is quite environmentally friendly, the actual process of producing large scale quantities may actually be more damaging than the fuel they are trying to replace. Unless there is a major breakthrough in production (possibly with algae?), I’m afraid that sustainable Biodiesel will be limited to small scale production dependant on the availability of waste vegetable oil, and won’t be a major player in the green movement.
Ethanol
Ethanol, like Biodiesel, is a plant derived alternative to oil derived fuel. Ethanol burns with 20% less CO2 than unleaded gasoline (petrol) and is particulate-free. The CO2 that it does emit was only recently in the atmosphere anyway so it can’t do much more harm. The fuel is renewable and offsets nasty oil usage. Most modern cars can run on a mix of up to 10% ethanol without any modification and vehicles can be produced to run on pure ethanol.
But like its cousin Biodiesel, Ethanol is not the green messiah it’s cracked up to be. According to the Economist article, Ethanol, schmethanol;“the amount of heat you get from burning a litre of ethanol is a third less than that from a litre of petrol. What is more, it absorbs water from the atmosphere. Unless it is mixed with some other fuel, such as petrol, the result is corrosion that can wreck an engine's seals in a couple of years.” Ethanol generally reduces the fuel economy of cars compared to normal gasoline. Ethanol production uses a lot of potential food, water and land as well as having distribution issues. It too is causing deforestation, this time in the Amazon. The clearing of forests has been said to build up a carbon debt which may take up to 420 years to make up with the CO2 reduction of ethanol usage.. Some have suggested the energy payback is too small for it to be sustainable (at least with corn). Some scientists have predicted an increase in respiratory health problems due to ethanol usage. As with Biodiesel, the wider cost of ethanol, especially in the light of other alternatives seems to limit its potential as the widespread replacement of oil based fuel.
I’m not sure how successful Biofuels will be in the future, they are certainly controversial. Large scale, I personally don’t think the ends justify the means when the humanitarian and wider environmental costs are taken into account. Future production breakthroughs may yield higher energy and emission paybacks but an energy source that competes with food production for land, water and fertiliser is only going to stretch an already overpopulated planet where there are plenty of people going hungry. This is not to say that Biofuels do not serve any benefit. I see a limited but nevertheless important role in the reuse of excess or waste matter to produce electricity with oil, food or even manure (via methane) that would otherwise go to waste. This is commonly referred to as biomass but the principle is the same as with Biofuels. Later in the week I will cover three options for turning electricity into motion for the cars of the future (and today).
 
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