Tuesday, 27 January 2009

"Greener" Cars

Peter Mandelson yesterday unveiled a package to support the UK automotive industry. It was stressed that this was to support the industry in its changeover to "greener" cars such as plug-in hybrid and electric cars.

Plug-in cars have great potential for reducing greenhouse gas emissions. However, there remains the question of how the electricity to power them is produced. Certainly with our current infrastructure, while the cars themselves are not producing problem emissions as long as they are running on the battery, the power stations which supply the charge for the battery are, often burning fossil fuels such as coal and gas to produce electricity. With the expected growth in renewables, this may cease to be a problem. If a "smart-grid" is used, it is even possible that plug-in cars could act as storage batteries for solar and wind-generated electricity, selling power back to the grid at times when demand is excessive or the turbines are not turning.

However, a major issue which must be addressed if electric cars are to be a truly viable resource is the battery material. Car manufacturers plan to replace the NiMH (Nickel Metal Hydride) batteries in their electric cars with Li-Ion (Lithium ion) batteries in the near future. While they can be recharged many more times than NiMH batteries, Li-Ion batteries are far from perfect, as anyone who has ever owned a laptop computer for more than a year can testify. Although re-chargeable, they hold an ever-decreasing charge over their lifetime until they are beyond practical use and must be disposed of and replaced.

It takes 1 million tonnes of lithium metal to make 5.3 million tonnes of lithium carbonate, which is what goes into Li-Ion batteries. Data from the US Geological Service (bit.ly/2LcRUd : based on a 1976 National Research Council report) says that global resources of lithium are about 14m tonnes, although Keith Evans (who worked on the original 1976 report) gives an abundance of 29.79m tonnes (http://www.worldlithium.com/AN_ABUNDANCE_OF_LITHIUM_-_Part_2.html). Even the more optimistic estimate doesn’t seem like nearly enough to keep our electric cars on the road for any length of time, especially as Li-Ion batteries are also used in other machines.

In 2007 global lithium carbonate demand was 93,000 tons, up 7.4% year on year, and China's battery output reached 33.4 billion, with an export volume of 25.168 billion: (source http://www.researchinchina.com/Htmls/Report/2008/5619.html). The Times reported on November 6 2008 that Japanese car manufacturers and electronics firms were adding lithium extraction and mining operations to their portfolios, indicating that they foresee increasing demand. Assuming that the US Geological Service’s figures are correct, this gives us less than 70 years worth of lithium, unless there is an improvement in mining and extraction methods in the meanwhile. But even then, this hardly constitutes as reliable a resource as, say, wood, which can be re grown more or less indefinitely.

There are several actions we might take to reduce emissions without over-exploiting our limited natural resources.



  • To avoid overexploitation of lithium, there could be greater investment in alternative transport: to move freight, we might, for example, use high speed electric trains powered by renewably generated electricity instead of trucks.

  • We could consider prioritising the needs of cyclists and pedestrians over those of drivers in our urban planning: this would encourage more people to leave their cars at home.

  • Taxation could be used to shift costs, reflecting the true inherent costs of petrol, for example, (while reducing income tax). This would increase the cost of car use which would encourage the use of alternative means of transport.

  • Mining and processing operations should be carried out with respect for the environment, the workers and the local population: this would almost certainly raise the costs of production and therefore the cost to the consumer, encouraging more careful use of our resources as well as raising the standard of living of the miners to an almost acceptable level.

Car manufacturers appear to view the Li-Ion car as a stop-gap while they attempt to develop completely different technology, probably hydrogen fuel cells. As a potentially cleaner fuel than fossils, this is a laudable aim. However, plans should be made to ensure that the Li-Ion car, which will inevitably become redundant, can be fully recycled and will not be the cause of yet more pollution at the end of its life.

No comments:

Post a Comment