The carbon costs of transporting food
We regard food miles as one of the most important things in reducing food's environmental impact owing to the amount of carbon involved in transportation. David Cebon is an engineer from the Centre for Sustainable Road Freight here in Cambridge who's working to reduce not necessarily the number of lorries on our roads, but their carbon emissions. Ginny Smith asked David why road freight is bad for the environment...
David - Well, road freight is an essential part of modern living. We can't live without road freight and we have lots of big vehicles, and they use a lot of fuel. But only about 20% of the total road emissions from road, so cars are actually a lot worse than trucks in the end.
Ginny - So, we have to get our food from where it's grown to where we buy it and to our houses. What can we do to try and reduce the amount of emissions that we're producing in that process?
David - The biggest part of emissions in that process comes from the last mile. That means picking it up in your car. The family car is the least efficient freight vehicle known to men. It weighs 1.5 tonnes and it carries 40 kg of freight. About 97% of the energy used to move that car goes in moving the car and about 3% in moving the freight. If you have a big truck, most of the energy goes into moving the freight and much less into moving the truck. So, the truck is much more efficient in fact than the family car. The best thing to do is home delivery.
Ginny - I actually in fact tend to order my food online and then you get a small - it's not exactly a truck, it's a van - delivering it; but I guess it's going on to other people and delivering other stuff as well...?
David - It's doing a whole lot of deliveries around the town and it saves all of those car trips. And all those car trips cause a lot of traffic congestion. Traffic congestion in turn causes a lot of fuel consumption. Everybody on the road uses a lot more fuel when the traffic is congested. So, if you can have a very efficient home delivery, it's definitely a big part of what we can do.
Ginny - Well, good to know that I'm being green, not just lazy! So, is there anything we can do to improve - I know that you've said the trucks aren't as bad as the cars, but what can we do to make them even greener?
David - There's all kinds of things that can happen that you can do to improve the fuel efficiency and the CO2 emissions of the freight system. They're broadly in two categories. One, kind of logistics things that how you arrange the system; and the other, I think, is to do with the vehicles. There's all kinds of possibilities with the vehicles themselves. In general, making the vehicles bigger is almost always better. So, the example of home delivery is one clear one. But if you can imagine that if you've got a delivery to a convenient store in town, if you have to drive two trucks instead of one, it uses a lot more fuel. So, if you can have larger trucks going into city centres, perhaps out of hours so that they don't get mixed up with the bicycles and kids going to school, then that's the kind of thing we can do to really improve that efficiency.
Ginny - That sounds like quite an easy thing to do, just make the trucks a bit bigger and send them in at night. Is that something that's being done?
David - There's been a lot of movement on that issue. The Olympics was a good example. In London, there were a lot more deliveries of freight at night. You bump up against people who don't like to have big trucks driving around towns at night and that's a problem. So, we've got a kind of a social dilemma - either we have more efficient vehicles running out of hours with the inconvenience perhaps of a bit of noise, or we have all the freight vehicles hitting the roads at 7:00am, which is what they do now - just when we're driving the kids to school and going to work - to beat traffic congestion time and park outside convenience stores and stuff. So, that is a sort of a social problem we need to sort out.
Ginny - And you've mentioned a few times that freight isn't actually the worst thing. What is it that's causing the most carbon emissions through the sort of chain of food being grown to getting to our plates?
David - Well, one other big issues, I think, is refrigeration: if you have a bottle of water and you refrigerate it. You bring it from France, and bring it on a boat and a couple of trucks. The worst part of it is if you actually put it in the fridge and leave it in the fridge in the supermarket for a couple of days before it's bought: then it uses a whole lot more energy. I think that the design of fridges in supermarkets is terrible. If you go to a supermarket, for example, at the railway station not too far from here, you see all the workers in thermal clothes because it's so cold in the shop - the fridges are pumping out cold. And there are heaters and fans. There are just piles of energy going into the shop, heat, and cold. What we need is doors on fridges and a bit of sensible policy in supermarkets!
Ginny - Thank you; David Cebon from the Centre for Sustainable Road Freight.