AT&T buys 101 GM cargo vans that are fueled by compressed natural gas.
Over the life of the vans gasoline may well go to $5 or more a gallon, so this may be a very good investment. I'm wondering how they'll be operated. I don't know about the current AT&T fleet, but the communications companies in our area (cable and telco) often have their vans idling for very extended periods (I've seen an hour around here). There is also an issue of dispatch and route planning. The local cable company doesn't do any of that. So a reasonable question is how efficiently is a fleet run independent of the fuel source.
Carbon emissions from natural gas are another issue. Burning natural gas only produces about three quarters the carbon dioxide per joule of energy as gasoline. Sounds like a win, eh? The problem is (a) this isn't a huge reduction if you are interested in carbon emission reduction and (b) it doesn't look at the life cycle analysis of the fuels.
Life cycle analyses are complex - they look at the energy used for mining, processing, transportation of the fuel and combustion. The problem with natural gas is that it is mostly methane - an extremely potent greenhouse gas. Leakage to the environment at any of the stages - by a few percent - can render NG worse than burning gasoline and even worse than burning coal. The devil is into the details. Some analyses suggest that natural leakage of the current NG infrastructure is sufficient to remove its advantage and recent analyses suggest shale coal mining (fracking) may release considerable amounts of methane making NG worse than burning coal. Much more research needs to be done and companies like AT&T have to be very careful about calling their NG vehicles "green" unless they have investigated the lifecycle impact of NG relative to gasoline or diesel fuel. Of course green may not be the point and NG may turn out to be much less expensive in fleets.
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