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Old 12-02-2007, 10:03 AM
Geof Geof is offline
 
Join Date: Jul 2005
Location: Canada
Posts: 11,558
Geof will become famous soon enough

Donna you are certainly a Pollyanna

Okay we all trade in our 20 mpg vehicles for 40 mpg and feel very virtuous.

But now we have created a huge CO2 pulse making those new vehicles so it is going to take more time before emission levels start declining.

All truck traffic is going to be transferred from highways to rail.

A very large proportion of long distance truck freight already goes by rail; that is what is meant by Intermodal. The bulk of the trucks you see on the highways are relatively short haul or final delivery and rail is not suitable for this. In addition according to the business magazines I read most rail systems are working close to capacity.

We should move toward a hydrogen rather than a carbon based economy.

This time I am going to be blunt: The hydrogen economy is nonsense.

Carbon containing fossil fuels are a source of energy which occur naturally. Free hydrogen does not occur naturally, hydrogen is not a source of energy. Hydrogen can be used as a fuel but first it has to be generated using an energy input. And a significant proportion of the input energy is lost during the generation of the hydrogen. One energy source that is used for the direction generation of hydrogen is natural gas but it is idiotic to use natural gas for this application because it can be used for almost all the applications the hydrogen can be used for. And natural gas consumes less energy for compressing and transporting because it is an easier gas to deal with. The other way to generate hydrogen is by electrolysis of water and this needs electricity so you are back to need greatly increased generating capacity. And in many cases it is probably more efficient to use the electrical energy directly.

it is possible to make concrete that incorporates significant amounts of recycled materials, such as slag and fly ash, reducing the amount of Portland cement that is needed. That is the kind of strategy that will help cut CO2 emissions in the future.

Quite correct. You have probably seen the concrete blocks with holes through them used for concrete wall building. In England they are called Cinder Blocks because they were a cheaper alternative to true concrete. Also a weaker alternative, much weaker. I don't think I want tall buildings, Nuclear reactors or big bridges made out of 'Cinder blocks'.

I could continue but I need my morning coffee.
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