Tuesday, September 25, 2007

A part of the solution

No single thing that we have done has led to our climate change problems. No single thing that we can do will solve them.

One thing that we have to do is use our energy resources more economically. Another is to find energy sources that do not put CO2 into the atmosphere and to reduce the amount of CO2 emitted by other sources. We have two main energy requirements, power for electricity and heat, and fuel or power to run vehicles.

We can supply electricity from sources that put no CO2 into the atmosphere. Nuclear, solar, wind , geothermal and hydroelectric are examples of such energy sources.

But we still need energy for vehicles. Internal combustion engines burning hydrocarbon fuels are a lightweight very flexible means of powering vehicles. But so long as we use petrochemicals , natural gas or the like they are a major part of the problem. There are difficulties using electricity in many vehicles. Overall it would be easiest if we could find alternative fuels.

One suggestion is hydrogen. This can be obtained by using electricity and the electricity can come from non CO2 emitting sources. Still hydrogen has problems with storage and with the embrittlement of metals that it can cause. It would be good if we could find a fuel source that removes as much greenhouse gases from the atmosphere as it adds.

This leads to biofuels. The idea is either to raise a crop that we can convert into fuel or to turn organic waste into fuel. The latter can only provide a small part of our energy need but every bit helps. The first can prove a lot more but there is a catch. Tho provide ethanol from corn or sugar cane or oils from soy beans etc. requires the use of a lot of agricultural land. It requires so much that it could seriously effect food production and with many crops we just don't have enough suitable land.

We need a better alternative and there is one. Grow algae in shallow ponds or plastic bags. It requires more than an order of magnitude less land than other crops used as fuel sources.

I was at a talk on research being done on producing algal biomass as a source of fuel. They are getting near. It is not yet economically viable but with current petroleum prices we are not far off. Work is being done to increase photosynthetic efficiency. An interesting possibility is the direct production of hydrogen by algae. This can occur under anaerobic conditions. Another possibility is that processing of the algal biomass can leave elemental carbon behind. This can be ploughed back into the soil in a very effective form of carbon sequestration.

And of course with such a source of fuel we can reduce our reliance on the Middle East. To the benefit of most of the world.

This of course is not the whole solution to our problems but I think it will be a big part of it.