Wednesday, 17 January 2007

Planes, Trains and Automobiles, Part 2

Last time we discussed the climate change impact of airplane travel. Bottom line: a couple of flights can easily wipe out all your other efforts to live a low-carbon lifestyle, so fly only when you absolutely need to and be sure to offset your flight's climate impact.

Now for trains.

Ground-based public transport is low-carbon because the emissions from the train or bus can be spread over a large number of passengers. A packed train does not consume much more energy than an empty one, so the more people you can cram into each train, the lower the emissions per passenger mile. Similarly, high-speed rail is not significantly more polluting than slower trains, so Government support for faster trains to replace short-haul flights can make a big difference. And with any luck you can walk or bike to the station - which is after all the cleanest and healthiest way to travel.

A moderately full train emits only 6.5 kg 65 grams of CO2 per passenger mile - about the same as three people in a hybrid car. But this is only a average figure. Actual emissions will also vary depending on the type of train and the operating company. For an electric train, the emissions depend on where the operator sources electricity. A train powered by electricity from renewable energy sources is essentially zero-carbon; while emissions from coal-fired electricity will be quite a bit higher. The same applies to diesel trains. Diesel trains can consume a huge amount of fuel, with higher than average per-passenger CO2 emissions. In fact, a half-empty diesel train may emit more CO2 per passenger mile than a small hybrid car. Richard Branson wants to tackle this problem by running the Virgin Trains fleet with a mix of biodiesel and regular diesel fuel. While biodiesel produced in the UK isn't carbon-free, it's still an improvement over business as usual.

As you pay your fare and squeeze into your train carriage on the way to work tomorrow morning, take a moment to smile at all the other passengers joining you on the way to a low-carbon economy. You might even enjoy the trip.

(Carbon Clear Homepage)