Two things make a post

[andrewducker]

1) If you care about the Digital Economy Bill then you should be wandering to http://www.theyworkforthebpi.com/ and then writing a letter/email to your MP letting them know that you will/won't be voting for them (delete as applicable).  Other voting issues may be more important to you, of course.

2) If your nearest recycling centre is non-local, how far is it worth driving?  I assume that someone smart has worked out a mile/plastic bottle ratio at some point, but I'm not turning anything up at the moment.

Comments

[lizw.livejournal.com]

This Green Lantern article says that recycling plastic bottles saves 55.9 GJ/ton compared to producing new bottles. There are similar figures for different kinds of recycled materials in this PDF (which also explains how to use the energy savings figure to estimate the greenhouse gas saving, if you'd rather look at it that way). You then need an energy use figure for your car to make a comparison - David Mackay says that an average family car will use 80kWh per 100 km. That page also gives a formula you can use to convert from J to kWh. Happy calculating!

[andrewducker]

My maths is clearly going wrong somewhere...

55.9 GJ/Ton = 55.9 MJ/Kg
There are 3.9MJ/kWh
So that's 14.3 kWh/kg

80 kWh/100km = 0.8 kWh/km

Dividing 14.3/0.8 means that it's worth travelling 18km to deliver a kilo of plastic for recycling.

That makes a lot more sense than my previous calculation.

[sigmonster.livejournal.com]

It looks like the 55.9 GJ/Ton figure is from a US article, which means it's most likely a short ton instead of metric tonne. However that's only about a 12% overstatement.

However, I see no real reason why the energy content of an equal mass of petrol has anything to do with the costs of extraction, fractionation, polymerisation and forming plastic. You don't refer to dietary calories to find the carbon costs of a steak, after all.

The main source of error seems to me that you're neglecting transport between the local drop-off point and the depot - that's going to take up some of the savings, too! It's likely to be more efficient per kg than your car is but also be travelling lots further.

[lizw.livejournal.com]

The main source of error seems to me that you're neglecting transport between the local drop-off point and the depot - that's going to take up some of the savings, too!

Green Lantern say that cost is unlikely to outweigh the cost of transporting raw materials for unrecycled products.

[drdoug.livejournal.com]

Ah, you updated just as I was about to post - I think you may have had an iffy figure for converting MJ in to kWh originally.

I think it's 3.6 rather than the 3.9 given at the moment - think of a one-kilowatt fire (=1000J/s) burning for 60s x 60min - but it gives you 19km as the answer which is as near as makes no odds).

[pete stevens (from livejournal.com)]

It's 3.6MJ/kWh (as there are 3600 seconds per hour).

http://www.channel4.com/food/features/wine-plastic-versus-bottle_p_1.html
http://g0mrf.com/rocketdemo.htm

A 75cl plastic bottle has a mass of about 54g, 50cl about 30g. That means you'd need 20-30 plastic bottles to get your kilo to take for recycling. That's certainly more than I manage in a week. Don't forget you have to drive back again (so 9km total).

For a single coke bottle, you get .58km, or a round trip of about 300m. That's a bit further than a typical tescos car park, but not much.

[pete stevens (from livejournal.com)]

For comparison, powering a mobile phone charge for a full year takes about 3.1MJ. Recycling two 500ml coke bottles saves 3.3MJ. You can offset your entire carbon emissions from not bothering to turn off your mobile phone charger by recycling two extra coke bottles, or reducing your driving by 1.2km - routinely parking at the end of the supermarket car park near the exit rather than the store would easily cover it.

[momentsmusicaux.livejournal.com]

> If your nearest recycling centre is non-local, how far is it worth driving?

Sounds like the sort of thing MySociety might create -- tell it how much stuff you have to recycle and it'll calculate which centres it's worthwhile going to. Suggest it to them :)

[pennski.livejournal.com]

Rough rule of thumb - if you have to drive there specially, it's probably not worth it. If you can combine it with some other reason to drive there, it is.

[missedith01.livejournal.com]

Yup. I can walk to mine but sometimes drive the bottles there but only if it's on the way to somewhere else that has to be driven to or I'm driving there for another purpose (it's at a local supermarket and sometimes I drive there altho it's in walking distance if there's a lot to buy).

[houseboatonstyx.livejournal.com]

We got a kit for making your own soda drinks which uses the same bottles over and over and it's great.

[luckylove.livejournal.com]

There's no point in writing to my/our? MP. He's fucking off into retirement.

[drplokta]

You don't want to recycle plastic. All of the oil is going to be extracted -- it may take 50 years or 100 years, but we'll get it all. If it goes into plastic which ends up in landfill, then the carbon is locked up for hundreds or thousands of years. If it's used for something else, then it ends up as CO2 in the atmosphere. So you want as much oil as possible to be used for making plastic, to sequester its carbon.

[randomchris.livejournal.com]

Plastic which ends up in landfill - annoying but acceptable. Plastic which ends up screwing up the world's oceans - not acceptable, indeed rather less acceptable than the equivalent amount of CO2. So it is worth recycling IMO.

[houseboatonstyx.livejournal.com]

Worth checking. Of course at some point they'll retrieve the plastic from landfill and ocean to make more whatever.

I'm a little sceptical about intact plastic trash piles swishing around in the ocean doing more damage than molecules loose in the air. Those piles should be easy to dredge up and recycle, whenever it becomes profitable.

[momentsmusicaux.livejournal.com]

Or we could get a clue and actually NOT extract all the existing locked carbon?

[cheekbones3.livejournal.com]

lol

[henriksdal.livejournal.com]

Remind me to explain how plastics have made us all doomed and there's nothing we can do about it when I get home. Or just google the mid pacific gyre, and what makes up 95% of the stomach contents of every single pelagic feeding organism.

[andrewducker]

Oh, yes, I know the gyre. I believe they've found an equivalent in the Atlantic as well now.

dooooom we're all doooomed

[henriksdal.livejournal.com]

I've linked to this before - take this and apply it to all species (I mean everything) that feeds in the top layer of the oceans/seas. If a dead fulmar washes up on a North Sea beach the Seabird Society will do a public autopsy at North Berwick's seabird centre because they know for a fact it's stomach will be full of plastic.

There's also a good lecture on TED about plastics in the seas.

[matgb]

Plastic gets collected from our door every week by the recylcing van. Ergo no driving required.

[andrewducker]

Ours goes into the recycling bin at the end of the street - Edinburgh's really good that way.