Working out the greenhouse gas (GHG) emissions of a truck ought to be pretty easy, right? If you know how much diesel it used, you know how much carbon it emitted. So far so good – but what if you want to know the carbon emissions per unit of product delivered? It gets a little trickier, but that’s not the real mind-bender…
Let’s say you go to the pub (by the end of this post, you’ll probably want to). You buy your beer and crisps, and then start to wonder what the associated GHGs are. (OK, you don’t, but humour me here.) The giant brewer BigBrew might have made your pint, and as of next April they’d be required by law to report their GHG emissions. But if a third party haulage company, let’s call them A2B, was contracted to deliver the beer to the pub, the truck’s emissions would probably not be reported by BigBrew. And what about your crisps? CrispCo, the manufacturer, would have reported their emissions, but A2B might have delivered those crisps to the pub too.
This is the first issue when deciding on how to report company emissions – where do you draw the line? In general, the global standard says that if you’re a business, you report emissions just on the stuff that’s directly ‘yours’. These are called ‘scope 1’ emissions (except electricity you buy, but we’ll leave that for now). How do you decide what’s ‘yours’, well, generally by whether you have ‘financial control’ of that thing – e.g. a building, a factory, or a vehicle. Financial control usually means you own or lease it, and you profit from its operation.
Lots of big companies don’t own the trucks that transport their goods – they outsource freight to other people. So it’s these hauliers that own the trucks, and profit from them, and the emissions from those trucks are the hauliers’ to report as scope 1.
So far so good, but what if the haulier isn’t really free to do anything that could reduce their emissions? In some cases, contractors provide vehicles and drivers, but the client specifies the vehicles, and decides what they’ll carry and what route they’ll take. In this case, it is possible to decide that the client has ‘operational control’ of the vehicles, and should count the emissions as theirs.
Of course, if I want to know the emissions associated with my pint of beer, I need to include transport in that. Let’s say BigBrew report the emissions from making the beer as their scope 1, and A2B claims the delivery truck’s emissions as their scope 1. In order to calculate the total emissions for the single pint of their product in my hand, BigBrew might ask A2B to give them a report on the emissions created by delivering each barrel of their beer. These emissions are described as BigBrew’s ‘scope 3’, i.e. emissions that are from another company’s operations, but which are ultimately associated with their product.
This could give A2B a bit of a headache. If they’ve got trucks which just deliver BigBrew’s beer, then no problem, they just calculate all the fuel/emissions from those trucks, and divide it by the number of barrels they delivered. However, they may well deliver beer from different companies, to a range of pubs, on the same truck. They could come up with a good estimate by allocating some of the truck’s emissions on the basis of the weight of beer delivered, and some on the basis of the distance travelled, or the number of stops made.
Now, I think you’d better pour yourself a stiff drink for the next bit. What if the truck isn’t just delivering beer? The amount of beer you can get on a truck is limited by weight. So you divide up emissions by the weight of each customer’s product. But what if you’re also delivering crisps? If you fill a truck with crisps, the load will be limited by volume. And if you have a mix of crisps and beer … don’t think too hard about it.
Two years ago I was the lead author on guidance for the freight industry on how to report its GHG emissions. I was one of a team of consultants working for the Department for Transport, with an industry steering group, to draft guidance to supplement the government’s general guidance to all companies, itself based on the Greenhouse Gas Protocol. That guidance is available on Defra’s website, and on my site here.
Working with Nick Gazzard of CILT, and Jaques Leonardi of Westminster University, we came up with simple(ish) mathematical answers to most of these problems. And we put them into a spreadsheet tool that’s also available on the Defra website.
But if you’re a haulier unlucky enough to be delivering crisps and beer on the same truck, for two different customers, I’m afraid we didn’t come up with a solution. I’m afraid that mathematically, you pretty quickly disappear down the rabbit-hole – and the only way to really solve the problem is to measure each truck’s emissions in the lab at different weights, and calculate it’s co-efficient of drag, and then model each individual stage of each truck’s journey.
Nobody’s suggesting hauliers should go that far. You just need to make a reasonable guess …
or maybe persuade pubs to stop selling crisps?