Scribblings for October 2005

Posted 2005-Oct-04 at The Oil Drum:

It doesn't matter how efficient we become - at least not in the short term, because we can't become highly efficient overnight - increased economic growth will require more energy.

Consider my concept, then:  instead of burning gasoline in engines at 17% efficiency, build cars as plug-in hybrids.  Efficiency under engine power goes up by a third, and 80% of their driving is done on grid power; direct fuel consumption falls by 85%.  The remaining energy (about the same 80%, due to losses) is met by burning oil:  70% of it by combined-cycle powerplants at 55% efficiency and 30% by simple-cycle gas turbine powerplants at 40% efficiency.  Total relative oil consumption is:

• 15% of baseline used directly.
• 17.3% in the CC plants.
• 10.2% in the simple-cycle plants.

Total:  42.5% of baseline, or a mileage increase of 135%.  If you get 30% of the additional grid power from non-petroleum sources like coal, wind or solar, this falls to 34.2% and the effective mileage increase rises to 192%.

Things look almost absurdly rosy if you postulate cogenerating furnaces to generate electricity during the heating season.  There are a lot of things we could do that we are not.  Yet.

Embarking on a plan like this would lead directly to economic growth because the money that would have gone to the oil-producing countries would go instead to the battery makers, gas-turbine manufacturers, and other uses inside the industrialized countries (including our own).

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Posted 2005-Oct-04 at Asymmetrical Information in a story about gas guzzlers:

Scary stuff on CNN.

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Landfill gas won't get us far

(not posted elsewhere)

Discussion about the possibility for hydrogen as fuel for airliners (and its prohibitive cost to produce, even from nuclear) led me to ask myself if much of the industry could be powered by landfill gas.

This required an estimate of gas production rates.  I doubt that an investment in infrastructure would be worthwhile if it would be useful for less than 20 years, so I looked at the numbers here and figured that 1.5 liters/kg/year is a reasonable production rate.  As for how much waste is in the landfill, I guesstimated 500,000 metric tons.  This results in a production rate of 750 million liters per year.

At a standard density of roughly 0.7 kg/m³, that much methane would weigh 525 tons.  At a guesstimated 100 tons of methane per jumbo-load (vs. 130 tons of kerosene), the production from a half-million ton landfill would be able to fuel about 5 jumbo jets per year.  In contrast, a 1 GW nuclear plant would be able to fuel several jumbos per day.

Landfill gas is clearly not going to replace more than trivial amounts of fossil fuel.