Posted: Thu 9th Jun 2022
When it comes to greenhouse gas emissions, a large percentage of your business's footprint is in how you and your staff move about.
Emissions are grouped into three 'Scopes'. Driving to and from work comes under Scope 3: emissions that your business doesn't generate itself, but are associated with its activities.
While hybrid working has likely reduced the number of days (and the emissions generated) people are commuting, it's still a significant portion.
But what are the options in reality? In this blog, we explore the measures and metrics of what just getting to work looks like.
To work out what emissions your business travel is generating, you'll need to know a few key figures:
How far do your staff commute? The average distance is around 10 miles.
How many days are they in? Every day someone works from home, transport emissions drop by 20%.
How do they arrive? It's important to break down by car size here, as this can have a huge impact.
To be more accurate, you can also gather information such as days worked per year and so on. It's recommended that you collect data for each member of staff and then combine the figures at the end.
A part-time employee who cycles to work will have a much different footprint to someone who drives every day in a diesel-powered vehicle, even if they're travelling the same distance.
Once you've done that, you'll need to start getting per mile usage stats. Our World In Data has a easy-to-read source that uses 2019 data from the Department for Business, Energy & Industrial Strategy (BEIS) – we use that data in this blog.
However, there's new data being published all the time, so you might find a different source you'd prefer to use for your own calculations.
All data is given in grams of CO2e (carbon dioxide equivalent) per kilometre. To adjust this into miles, we've multiplied all figures by 1.6.
It's worth noting that these figures take into account the whole lifecycle of the fuel and vehicle. That is, the emissions generated from the extraction, transport and refinement of the petrol, and not just the tailpipe emissions.
This gives a much more accurate picture, especially with electric vehicles charged by the grid (which isn't entirely green yet).
With cars, there are two main factors:
Type of fuel
Size of vehicle
Let's compare two petrol vehicles:
Small petrol car (e.g. Volkswagen UP!): 246g per mile / 2.46kg per 10 miles
Large petrol car (e.g. Kia Sportage SUV): 452g per mile / 4.52kg per 10 miles
The two vehicles use the same fuel source, but the heavier, larger vehicle produces nearly double the emissions. If you're car-sharing, this may not be as much of an issue – although the average car occupancy in the UK suggests commuting is mostly a solo affair.
We can now look at two electric vehicles:
Small electric car: 73g per mile / 760g per 10 miles
Large electric car (e.g. SUV): 107g per mile / 1kg per 10 miles
Here, the difference is smaller but still considerable. The smaller difference is explained by the fact that electric motors are incredibly efficient, converting around 85% of the energy they consume into motion.
By comparison, a petrol engine is around 30% efficient. Consequently, if the car is heavier you need much more fuel to move the same amount.
These differences are fairly minor individually, but they become apparent when you look at a yearly carbon footprint.
Let's assume we're commuting 10 miles a day, five days a week, and working 48 weeks of the year. That makes the formula:
(g per mile) x (round trip) x 5 x 48
Example (small petrol car):
246g per mile x 10 miles a day = 2460g
2460 x 5 = 12300g per week
12300 x 48 = 590400g or 590kg
A small electric car charged off grid energy has a footprint that is around 85% smaller than a petrol SUV.
Small petrol car: 590kg
Large petrol car: 1084kg
Small electric car: 175kg
Large electric car: 256kg
It can be hard to put these figures into context, so let's consider how many trees we'd need to plant to offset the amount of emissions.
A mature tree can sequester (capture and store) around 22kg of carbon dioxide every year. However, new sapling trees, such as those you're planting, are likely to only sequester a fraction of this – around 2kg or 3kg per year.
Let's assume 2kg because your emissions are now, and you need to offset what you're producing today – not in 20 years' time once the tree has grown.
Small petrol car: Yearly footprint of 590kg = 295 trees needed to balance
Large petrol car: Yearly footprint of 1084kg = 542 trees needed to balance
Small electric car: Yearly footprint of 175kg = 88 trees needed to balance
Large electric car: Yearly footprint of 256kg = 128 trees needed to balance
Trees are priced at around £6 each in the UK, so you do the maths on how much it could cost!
Cars are pretty energy-intensive as typically only one person uses them. They also require a lot of energy to move around. But what about public transport or bikes? This is where the difference becomes significant.
Bus: 168g per mile | Yearly footprint of 403kg = 200 trees needed to balance
Train/tram: 56g per mile | Yearly footprint of 156kg = 75 trees needed to balance
Electric bike: 3g per mile | Yearly footprint of 7kg = 1 tree needed to balance
As many buses use diesel, they're quite high polluters compared to the alternatives. However, more fleets are becoming electric or hybrid, and so the data here (from 2019) may be out of date.
Trains and trams, on the other hand, demonstrate significant reductions, even when measured against electric cars – just 56g per mile compared to 73g for a small electric car.
Even better is the electric bike. Because they're powered, people can cycle much further on them. There's less strain on the body, and commuters aren't arriving at work with the dreaded cycle sweat. For this reason, we highly recommend that you invest in an employee cycle to work scheme!
Compared to a car, an electric bike is incredible value and boosts employees' productivity and wellbeing, especially during summer. Would you rather be getting some exercise or stuck in a traffic jam? Plus the more people cycling to work, the less traffic there is.
There's a lot of information to take in, but calculating this data for your own business is relatively straightforward and something you can do easily with a spreadsheet.
Begin by gathering up how far everyone comes in each day and how they do it. From there, you'll be able to quickly add in emissions data to build up a footprint. It's a start!
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