I must admit that the prospect of a $7,500 car that can run for 200-300km on $3 worth of compressed air sounds pretty amazing. Of course, the compressed air would just be a storage mechanism for energy generated in other ways. The advantage over hydrogen and fuel cell systems of biodiesel could lie in lower infrastructure costs. Installing compressors in homes and service stations already connected to the electrical grid is a lot cheaper than developing a whole new hydrogen infrastructure, leaving more money to direct towards genuinely renewable sources of energy. The compressors could also be powered directly by wind or water turbines, as well as solar power systems. As for biodiesel, once you factor in the energy required to grow the crops and process them, as well as the inefficiency of internal combustion engines and the continued reality of toxic emissions, it doesn’t seem like a hugely alluring prospect to anyone but corn farmers.
While it is unlikely that one technology will allow us to overcome fossil fuel dependence, it does seem sensible to think that something like this could be part of the mix. Especially if the energy being used to compress the air is coming from a renewable, non-greenhouse-gas-emitting source, these cars could make a big difference in the developing world. They could also help tackle urban air pollution, such as the kind plaguing Beijing.
PS. I got today’s photo of the day in Oriel College, as part of my initiative to photograph each college at least once. While there, I discovered a sizable conference on climate change ongoing, about which I had heard nothing. This goes to show just how many people are working on the issue, both here at Oxford and more generally.