fivemack (fivemack) wrote,

Where's my error?

I've often heard arguments like 'the cost of flying should reflect its externalities', where the clear implication was that this would make it so expensive that people would stop doing it, or so expensive that it would clearly be cheaper to take a train.

On the whole I'm strongly in favour of air travel - at least, I'm strongly in favour of at most one-level-vicarious personal experience of strange far-off places, and air travel is the only realistic way to get anyone there; going over land to Bangkok is significantly more expensive than Thai Air even if time and ludicrous inconvenience are not a constraint, the price of the return plane ticket won't get me a train beyond about Moscow.

Yes, it takes a lot of energy to remove one ton of CO2 from the air: says fifty kilojoules per mole which is 1.2 gigajoules per ton, is optimistic and says a third of that.

A gigajoule is about 300 kilowatt-hours, so about thirty pounds worth of electricity at the price I pay for it as a domestic user on a not-terribly-good-value tariff. Say the cost-of-capital and depreciation for CO2-removal equipment is about the same as the electricity; so the total cost for taking CO2 out of the atmosphere would be sixty pounds a ton.

Even people strongly against CCS no-net-CO2 coal-fired electricity generation argue that the efficiency cost of doing the CCS would be about 30%, the currently-4GW facility at Drax would produce 2.5GW; say this doubles the price of the electricity and we're talking a hundred pounds a ton.

One of Easyjet's A319 planes burns 850 gallons of fuel an hour to transport say 120 people (capacity is around 150); jet fuel produces about a ton of CO2 per hundred gallons burned, so taking your 120 people two hours to Berlin has produced about twenty tons of CO2. Removing which would put £17 a head on the cost of the flight; Easyjet is nothing if not cheese-paring, so it probably wouldn't put £30 a head on the price of the ticket. +30%. The last time I compared the prices, Easyjet to Berlin was £100 return and rail was £400 one way.

A Eurostar train carries 750 people two hours from London to Paris and uses 12.5 megawatts of electricity to do so; 25 megawatt-hours at a kilo of CO2 per kilowatt-hour for UK electricity generation [yes, I know most of the French electricity is fission-produced] is 25 tons, so about the same amount of CO2 as the A319 to get six times as many people about half as far. I don't have the figures for slower trains.

A 747 with its 400 passengers burns about a gallon of fuel a second, say produces 36 tons of CO2 per hour, it's eleven hours to San Francisco so that's 400 tons, £24000 to remove. A hundred pounds per passenger per direction; say £250 on the price of the return ticket. +30% again, maybe a bit worse if you're flying at very off-peak times and can get a cheaper base ticket.

Flights aren't the overwhelming part of the cost of foreign holidays now; making them 30% more expensive doesn't seem likely to stop people travelling, and if doubled electricity bills and somewhat more expensive holidays are the price I have to pay to keep London (and incidentally Bangladesh, for there is only one sea level) above water, I'll pay gladly.
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