Dave's Free Press: Journal

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Fri, 24 Oct 2008

Ocado delivers ... The Times?

The nice man from Ocado just delivered my groceries. I order stuff slightly more than once a month. Included in my delivery was a copy of The Times.

This is most puzzling.

It was today's newspaper, delivered just before 9pm - so if I actually wanted to read the thing (and I don't - what, get the news on paper? How 20th century!) I'd have already bought a copy at the station 12 hours earlier, read it, and discarded it. So they're obviously not delivering it so that I can enjoy reading it. And then, Ocado do like to trumpet their green credentials. Exactly how delivering a mass of useless paper which is only going to get thrown away is green is beyond me.

Posted at 21:15 by David Cantrell
keywords: environment | media
Permalink | 3 Comments
Fri, 27 Jun 2008

How to Save The Planet, in one easy step

Hippies would have you believe that you can Save the Planet and your wallet by unplugging your devices instead of leaving them on stand-by. They are wrong. If we assume that each of twenty devices in my flat is wasting 2W for the 23 hours a day that they're not in use (all of which are pessimistic estimates), then that's wasting 3.3 mega-Joules a day. That sounds like quite a lot. It is, however, just under 1kWh (the unit in which electricity is metered) so costs about 10p a day, or £3 a month.

Here's a much better way of saving energy, emitting less "carbon" (carbon is in fact Just Fine, it's carbon dioxide that will destroy the planet), and coincidentally saving quite a bit more money.

Drive slower.

I recently took a round trip of about 500 miles, most of it on motorways and other fast free-flowing roads. By driving at 60mph instead of 85, I got 45 miles per gallon instead of my normal 33-ish. That means I burned 4 gallons less fuel, or 18 litres, or £24.50. Given that the energy density of diesel is about 38MJ/l, I saved 684MJ or 192 kWh. That is, in one weekend I Saved the Planet as much as I would in nearly eight months of unplugging the hifi, phone charger, etc.

And never mind how much my back thanks me for not having to do all that bending over to plug and unplug things.

Anyway, now let's see what happens if we apply my wisdom to the whole country. Let's conservatively assume that there are 1,000,000 cars, each doing 10,000 miles a year, and that they all normally do a quite good 50mpg. That means they burn 200,000,000 gallons of fuel, or about a billion litres. If everyone slows down by the same amount I did, that billion litres becomes 700 million litres, saving 300 million litres of petrol (which is cheaper than the diesel I use), or 354 million quid. That's also a saving of 12,000,000,000,000,000 joules of energy. Which is about the annual output of the Enfield power station.

What's really interesting about this is that Enfield is a very small power station, about a twelfth of the size of Drax. So while driving slower is a fuck of a lot better than unplugging your phone charger, it's also still not very effective at Saving the Planet. You should still do it though, cos it'll annoy the BMW driver behind you.

[updated to ignore engine efficiency - even if your engine is really inefficient you're still turning each litre into 38MJ of energy, just not very usefully]

Posted at 09:24 by David Cantrell
keywords: cars | environment | transport
Permalink | 2 Comments
Sun, 6 Aug 2006

Congestion vs environment

According to The Observer, MPs are surprised that "while a national road-charging scheme to charge motorists by the mile is being piloted, its aim is to cut congestion, not to discriminate between a higher-emissions Land Rover and an environmentally less damaging Toyota Prius".

You see, that's because road usage is not the best way of determining how much environmental damage a vehicle does. The total pollutant output is, over the lifetime of the vehicle, pretty much proportional to the amount of fuel put in to it. Consequently, while road charging may be a great way to ease congestion (as has been proven in London), if you want to reduce environmental damage, you need to encourage the use of more fuel-efficient vehicles instead. The way to do that is to charge more for fuel and perhaps to subsidise the purchase of efficient vehicles such as the Prius. It is an entirely different problem from congestion, and so is best solved in entirely different ways.

Posted at 22:58 by David Cantrell
keywords: environment | politics | transport
Permalink | 0 Comments

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