On 24 March 2024 Lee Anderson, the former Labour Councillor, Former Conservative MP and now Reform Member for Ashfield and Eastwood posted on X a video clip in which he said the following:
“Ey up Lee, Member of Parliament for Ashfield and Eastwood. Just cut my lawns with this electric lawn mower, it’s got batteries on look, look at that, it’s net zero at it’s finest. Trouble is, I’ve charged this up earlier on today and probably the electricity’s come from Ratcliffe power station about 10 miles down the road, that runs on gas and sometimes coal. What a load of nonsense that is Net Zero.”
The Grantham Centre Green Watch team thought that this short video raised a lot of interesting points, and offered a good opportunity to address some popular misconceptions that often come up when looking at the role of electrification in decarbonisation.
Well the Erbauer EXT ELM18-Li Cordless 36V Lawnmower that Mr Anderson looks to be using is sold exclusively by B&Q in the UK. Looking at their website, there isn’t any mention of “Net Zero” or “Low Carbon” in the sales literature, so maybe that’s not why people are buying the mowers. A review of Google search terms shows that 10 years ago people were much more interested in petrol mowers, followed by electric, with battery lagging behind in third. Over the last decade interest has levelled out.
Articles on the subject suggest that as battery technology has improved consumers are enjoying the benefits of electric mowing and the freedom of not having their range limited by a cord.
Maybe cost is a factor. Well, if we go back to our DIY retailer they sell a very similar model of mower powered by petrol, for the same price. However, looking at the running cost of the two, we start to see a difference.
The petrol mower does have a wider blade so we’ll make allowance for that, and we’ll imagine that we want to mow for one hour in each case, just to make the maths easier.
The battery model uses a 300W charger, takes an hour to charge, and runs for 25 minutes, which equates to an energy use of 0.72kWh per hour of mowing and this equates to about £0.18 at 2024 average electricity prices.
The petrol model has a 0.9 litre tank and uses fuel at a rate of 1.4 litres an hour, this is 12.6kWh of energy at a cost of £2.01 at typical pump prices.
We did also say that the petrol model has a slightly wider blade, so allowing for that the battery model might be cutting for 10% longer. Upping its cost for the equivalent area to £0.20, we can estimate that the battery model is operating at 10 times less the cost of the petrol model.
So, in a cost -of-living crisis, a battery powered mower might have the edge for most consumers.
Ratcliffe-on-Soar power station is located in Nottinghamshire and is the last remaining operating coal fired power station in the UK. It has an electrical output of 2GWe and is connected to the 400kV electricity transmission network.
The UK has a national transmission network of high voltage power lines, the “national grid”, onto which the majority of large scale power generators are connected. This accounts for around 71% of the electricity used. A smaller quantity of embedded generators are connected to district networks, and the whole system is arranged to balance supply and demand.
Although, through contractual arrangements, consumers can specify the nature of the power they receive – for example 100% renewable tariffs – the reality is that we all receive a mix of electricity from multiple sources. Living 10 miles from a power station gives you no greater claim on that power than a user at the other end of the country.
Websites exist that can tell you the generating mix minute by minute, and many people were quick to share that information with the MP.
The Grantham Centre Green Watch team assume that this final statement is a reference to how much carbon was emitted in mowing Mr Anderson’s lawns.
Luckily for us, the UK Government publishes annual updates of the carbon intensity of the fuels and power sources we typically use to allow informed decisions to be made.
Using this data and the previous calculation of energy used by the two types of mower, we can see that the battery mower’s emissions would have been 0.16kgCO2e for an hour’s use, compared with 2.94kgCO2e for the petrol – 18 times less.
So, whether it’s for convenience, running cost, energy used, or carbon emitted, Mr Anderson’s new mower would seem to be a winner. We will have to wait for the next General Election to see if its owner is as successful.
In compiling this story the Green Watch team were led on many different tangents, not all of which we had the space to cover. But even in a relatively simple assessment like this it’s important to think about the bigger picture such as:
• The difference in embodied carbon between a petrol and battery mower • The expected life of the mower, the maintenance and end-of-life requirements • And finally should we be mowing our lawns so much? What are the biodiversity implications of schemes like No-Mow-May or leaving wider borders to encourage wildflower growth?
We’re sure to be back to pick these topics up in future articles.
Do you have thoughts on this, any other examples of greenwashing or a confusing use of sustainability concepts that you’d like our team to investigate? Get in touch on grantham@sheffield.ac.uk!