Start Your Engines! Green Vehicles Make the Running

28 May 2008

Start Your Engines! Green Vehicles Make the Running

Which came first - the petrol internal combustion engined car or one powered by electricity? If you thought the former, you would be wrong: Robert Anderson of Scotland made his first electric vehicle around 1834. It wasn't until 1885 that Karl Benz created the first petrol-powered car. In 1900 when Rudolph Diesel exhibited his innovative motor vehicle, it ran on peanut oil: he had envisioned it being powered by biofuels created locally from nuts or seeds.

There's no overwhelming reason why we have 800 million internal combustion engined (ICE) vehicles propelled by fossil fuels on the road . A combination of technological factors, the cheapness of oil from the USA during the early part of the 20 th century, and the sheer convenience of petrol and oil (liquid, easily transportable, lots of energy per kg) made them the fuels of choice for the 20th Century. From battleship to Boeing to bubble car, oil made them all possible.

And virtually everyone had no idea that they were producing environment-wrecking greenhouse gases.

We know better now. Many other vehicle designs are coming onto the market. Hybrids, Electric Vehicles, Hydrogen fuel-cell cars, and a plethora of other sources of energy to move from here to there have been proposed.

The spectrum is wide: from practical cars to wild and woolly “concept” vehicles.

The more conventional options are petrol or diesel hybrids, with electric motors to provide regenerative braking and low-speed electric motoring around town; the more advanced plug-in hybrids, which are a development of the former, which use more electric power rather than fossil fuels. Fully electric vehicles are perfectly possible as local runabouts, but currently cannot compete on speed or range (45 mph and 150 miles).

LPG cars, using pressurised Liquid Propane Gas, have slightly lower emissions than equivalent petrol vehicles, because of the smaller amount of GHGs in the fuel. Although fuel costs are lower too, this could change because of the volatility of world hydrocarbon fuel prices.

Hydrogen cars look like being an expensive dead-end. The complexity, the problems of making fuel from water, and the difficulties of retrofitting an entire infrastructure designed for petrol and diesel, make this an unlikely option for the future. In addition hydrogen isn't a fuel, but a fuel carrier. More electricity would have to be generated to create hydrogen from water. This would have pollution impacts if it was not made from renewable sources. Mazda are going to sell a petrol/hydrogen dual fuel car this year, the RX8-RE but this looks mostly like it will drive on conventional fuel.

More exotic transporters exist. Cars driven by compressed air have been proposed. These also suffer from technical problems like the hydrogen car. Although it seems an attractive option, and some are projected to go on the market in the next few years, it seems unlikely to be able to be “scaled up” to be anything more than a curiousity.

Solar powered cars have been invented, using photovoltaic panels on the roof, but these are more like exotic concept cars then practical vehicles – they usually only have one person, the driver, and no luggage space, being used for racing each other.

If we ignore the impractical or far-off from market vehicles, what are the current options? We have to remember that we are looking at full-lifecycle emissions, which includes the environmental and energy cost of manufacturing the car, its fuel, and the disposal or recycling of it after its useful life is over. All of this has costs, in terms of energy and carbon, as well as money.

The high price of oil has made hybrids increasingly popular. Manufacturers are struggling to keep up with demand. There is a six to eight month waiting list for the bestselling Toyota Prius for example, which has just passed the one million global sales mark.

The G-Wiz electric car has become popular: GoinGreen launched the G-Wiz in the London in May 2004. There are estimated to be around 900 of these on the roads. The 2008 Model G-Wiz i is the most advanced version of this iconic EV and provides improved safety, vision and comfort. It has range of up to 48 miles per charge, a powertrain designed to be upgradeable to high performance lithium-ion batteries, nippy acceleration and maneuverability, and a certified top speed of 50 mph. A major part of its appeal must be its tiny size making it much easier to park in crowded cities. The Electric Vehicle Association of Canada calculates that driving an EV improves CO2 emissions by between 55% and 99.9%.

There is an option for filling your car with biodiesel. If it's made from used vegetable oil, then you can call yourself a full greeny. If instead it comes from jatropha or palm oil from plantations that were originally tropical forest, then the net outcome is not very green, and that's before we have factored in people starving because their foodstuffs are bing converted into biodiesel to obtain subsidies. Biodiesel blends can be used in many “ordinary” diesels, or the vehicle can be specially converted. You can make your own in your own garage in a Heath Robinson kind of a way or you can purchase a biodiesel maker. Green Fuels is a company that provides equipment, on a domestic or commercial scale, to convert used cooking oil, oil seed crops such as rapeseed, or unused vegetable oil to biodiesel which is biodegradeable, non-toxic and carbon neutral and because it has 80% lower emissions than mineral diesel, it dramatically reduces pollution.

Photo: Antony Thompson/TWM

Similarly, bioethanol can be used to power cars. This has been particularly successful in Brazil, where there is lots of sugarcane feedstock, but is not perhaps so useful for the UK.

Vehicles can be powered by gas, either natural gas, or liquid propane gas (LPG). Though it is perfectly possible to power vehicles in this way, the inconvenience of storing and using a gas over liquids like petrol or diesel have made it less popular. Neither of the two main problems: greenhouse gas emissions, and finite fuel stocks, are solved by this method of transport power.

Finally, one other green method of power has hardly been explored: gasified wood burning vehicles. It sounds like something out of “SteamPunk” science fiction (science fiction set in a brass-and-rivets Victorian world), but actually has some ecological credentials and an unusual history.

During WW2 many countries who were under Nazi rule had no petrol as it was used almost exclusively for the German war machine. In order to keep vehicles going they were converted into what the French called “Gazogenes”: these burned wood or charcoal in a sealed gas vessel and the gas is then used to power a converted ICE engine. These vehicles are slower and more cumbersome than a normal car, so weren't very popular – after the war had ended they were scrapped or converted back to conventional engines, but the advantage of wood gasification is that it does not release any more carbon back to the atmosphere that came out of it already (as the tree grew and absorbed it.) So these are more eco-friendly. Some commentators have suggested that as shortages of oil bite, and as the oil has other, more socially valuable uses, such as pesticides and pharmaceuticals, we should convert cars to new “Gazogene” type sustainable vehicles. I'm not entirely convinced but it is an amusing idea.

What sort of cost savings are possible?

It is always difficult to say exactly how much cheaper motoring can be with various options, but estimates that using a high mpg car would save between 1.2 and 1.5 p per mile, with a hybrid saving 25% more. There are of course vehicle excise licence and congestion charge savings possible as well. EVs are cheaper still: Goingreen claim that the G-Wiz's electricity costs over a year would be equivalent to one fill-up of a regular car's fuel tank. This may not be quite so much a saving as the lifetime of the batteries has to be taken into account: they will be expensive to replace.



The Carbon Managers Ltd - The Green Building - Beckington - Bath - BA11 6TE
Copyright @ 2019