Wednesday, May 23, 2007

Electric cars, part of a future low energy, low emissions future.

Decarbonising transport is not an easy goal to achieve. Biofuels may be part of the
 solution, but chosen poorly they are part of the problem. The sheer scale of the demand for transport related energy is a huge issue.

No matter which source of energy you look at you have trade offs. As with the whole energy sector it is effeciency that is key. There is some debate over the best technology to be used for transport. Some very well respected energy analysts suggesting that hydrogen via high temperature reforming is a viable solution. This process is far more energy efficient that electolysis at present.

However, hydrogen storage is a tricky issue and transporting hydrogen is non-trivial. One technology that we already have is battery powered cars. Battery design is advancing apace, the price is still high but with sufficient interest, and large scale manufacture, electricity is becoming the energy storage medium of choice.

Whatever that medium of energy storage, total system efficiency is key. The generation of electricity is typically 35-45% at large scale power station, if both electricity and heat are generated as is currently the case across denmark then efficiency of >95% is possible. If better car designs and technologies are used then energy usage compared to average cars can be doubled, trippled or more.

Combining this 95% overall energy efficiency of the energy infrastructure with the doubling or trippling of efficiency of energy usage we have a radically low carbon system whatever the fuel.


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1 Comments:

At 4:49 AM, Blogger Steven said...

Hi,

The goal you have is good, and improving efficency is good too, however, maybe we have to start thinking about limits to growth.

Whatever improvements we make in efficiency, will be lost through countries like China and India trying to have their version of the American Dream - which is big cars, houses, appliances, shopping centres etc etc, which all uses energy.

Now, even without that, have a look at the blackouts happening in California because of too much demand for electricity. The power system is already stretched to its limits. As you correctly point out, transport uses a lot of energy. Now imagine everyone switching from oil, for example because of peak oil to electricity to power their cars, whatever way that is, whether with batteries or with hydrogen. The system would fail.

In Australia, where I am from, coal fired power stations are running out of cooling water. We don't have enough rain, and probably due to climate change. Farmers are doing it very rough, with not enough water for the crops. Nature seems to be already limiting the energy available to us. Its probably its self-regulating nature. I think in the near future we will see nature "shutting down" its services because we have pushed it to the brink. Water will become more scarce. Oil will become more scarce.

The whole mess we've done to planet earth will come back to haunt us. Pay time is comming. So far we've got away with most things, and we've had a free ride, but Gia will take revenge. Just watch. Techno fixes won't help (perhaps minimally). We have to scale back civilisation, and consumption, thats what we have to do. Nature has its limits, and our population has reached overshoot. If you look at the ecological footprint of mankind, we would need several planets to sustain out way of living.

Changing the whole car fleet will take decades. Not everyone can afford it either. With peak oil, people will simply have to drive less, and use public transport more.

Public transport is a lot more efficient than cars - buses, and trains even more. Buses could more easily be fitted with more modern technologies, or different fuels.
Cars also have a much higher social lost (lives lost).

So, we should stop car dreaming. The love affair has to end. Just look at how Japan and Holland use mass transport and bicycles to get around. If you want im sure you can find the BTU used per passenger mile for the different modes.

 

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