I recently bought an electric lawn mower. I’m not one to gush (or really care) about lawn equipment (or my lawn, for that matter), but I must say my electric lawn mower is amazing. I feel like it has changed my life. And apparently I am not alone. I read an ACEEE study recently that highlighted how electric lawn equipment is a gateway technology for further home electrification. Of course, my evaluator brain immediately jumped to wondering about how utility programs claim any savings related to the additional electrification.
Why Electric Lawn Mowers Are Awesome
According to the EPA’s 2020 National Emissions Inventory (NEI) data, lawn and garden equipment emit more than 30 million tons of CO2 per year in the US. They are also responsible for more than 68,000 tons of nitrogen oxides, nearly 22,000 tons of fine particulates (PM 2.5), and 350,000 tons of volatile organic compounds. In addition to the global warming impacts of the CO2, lawn equipment spews a lot of nasty stuff into the air right around where people live, leading to asthma and other health issues.[1] Swapping gas-powered equipment with electric equipment drastically cuts those emissions.
First person perspective of mowing with an electric lawn mower
Similar to electrifying cooking equipment, swapping out gas-powered lawn equipment with electric versions have many other non-energy impacts beyond health impacts. In the month I have had an electric lawn mower, I have noticed several benefits:
- First, the electric version is much quieter than the gas-powered version. For some reason, my kids have a strong need to wait until I am doing something loud like mowing the lawn to ask me questions, which results in many stops and starts as I answer them. The electric lawn mower is so much quieter that I can answer them while still mowing.[2]
- Second, it is notably lighter. Although it is self-propelled, I rarely need to engage that feature. These two attributes together mean that my 12-year old now is able to easily and safely mow the lawn instead of me.
- Third, there are no more trips to the gas station to fill up a gas can which leaves the inside of my car stinking for a day, giving me a headache.[3]
- Another benefit is that because the mower does not have a gas engine, I no longer need to worry about a gummed up carburetor after a winter of storage and the related expense.
- It has headlights (?)
I’m sure there are more non-energy benefits yet to be realized, but so far the switch has been a no-brainer. The only drawback of the switch is that now that my son has taken over mowing duties, I no longer get to spend an hour or so every weekend listening to music or an audiobook while mowing.
Electric Lawn Equipment as a Gateway Technology
According to the ACEEE study, people with electric lawn equipment were much more likely than others to want to electrify other end uses. Specifically, they were 84% more likely to want to electrify their cooking, 33% more likely to want to electrify their home heating, and 32% more likely to want to electrify their water heating than someone without electric lawn equipment. The study speculates that the increased propensity to electrify other end uses comes from positive hands-on experiences demonstrating the benefits and reducing some perceived barriers of electrification.
If these people install these additional appliances, would utilities/program administrators be able to claim any additional savings?[4] The answer is yes, but they might be missing out on the full extent of net savings if the net impact evaluation is not well thought through.
Savings Attribution
There are two ways a program administrator could claim savings from the additional electric equipment. First, would be as spillover coming from a program that incentivizes the electrification of lawn equipment. Because the upfront cost of electric lawn equipment can be higher than gas-powered alternatives, many utilities offer incentives to help defray the cost. The program could claim as spillover any energy savings measures (electrification or otherwise) installed outside of the program but as a result of the program’s influence. However, these spillover savings may not be quantified because lawn equipment rebate programs tend to be small and therefore not evaluated with the same rigor as larger programs (i.e., the evaluation likely will not include spillover research). Given the types of equipment that could be installed following participating in the lawn equipment rebate program, the amount of spillover savings could be large and worth researching.
A program administrator may instead claim the savings from the additional installed equipment through a program that targets that equipment (e.g., a residential HVAC program offering incentives for a heat pump), assuming the customer participated in the program. These programs will likely have net-to-gross research as part of their evaluations, but for these programs the main concern is the treatment of free ridership for the additional electrification measures. When conducting free ridership surveys, evaluators should be aware that participants’ experience with the electric lawn equipment is a potential driver to participating in other programs and that the respondent may not realize this. The respondent may not attribute much program influence in their decision to install the equipment because it may not be an obvious logical connection between their positive experience with a lawn mower and their decision to install a heat pump or induction cooktop. This could result in a relatively high level of free ridership. If the evaluator does not structure the free ridership questions appropriately to account for this, then the program’s net savings may be lower than they should be.
[1] Note that many articles about this topic include statistics stating that a push mower emits as much hourly pollution as 11 cars and similar talking points. I saw these stats everyone and had a hard time tracking down the original EPA source. It turns out that these statistics are from at least 2007 and are likely outdated due to changes in standards for both lawn equipment and cars. The general point still stands, though.
[2] It is probably not a stretch to think that the lower noise also reduces long term hearing damage as well.
[3] Millions of gallons of gasoline are also spilled every year filling up lawn equipment.
[4] Assuming it is allowable under the local regulatory framework.