EV emissions calculator

When we built our house we tried to build enough infrastructure for our needs: we wanted to be thoughtful consumers. We collect our own rainwater (which covers all our water needs, including irrigation). We have a septic tank which has been pumped out once in 13 years. We avoid putting too many chemicals down the drain to keep the biota in good condition, and, as a result was only half full when it was pumped out after a decade, so wouldn't have actually needed emptying for quite a long time yet. We have a vege garden and compost appropriate waste. There isn't much we can't deal with ourselves.

As well as water and waste, we have photovoltaics (PV) on our roof, and a grid-tie system. What that means is that we use the power of the sun to power our energy use during the day, but - instead of having to buy batteries, we are tied to the national grid. The grid takes our excess generation (the power we are unable to use during the day), and gives us a credit to consume at night. Also during the night - on off-peak rates - we recharge the battery of our EV. 

There has been a bit of grumping in the media of late about just how environmentally unsound EVs are (Lane, 2023). So I decided to go looking to see if I could get a rough idea of what emissions there were. According to the Transport Environment calculator, my 'solar powered' mini emits roughly 46g of carbon per kilometre (2022; halfway down the page here). A petrol car of the same size apparently emits 215g/km (Transport Environment, 2022). Including manufacturing costs, a petrol car emits 4.7 times more carbon per kilometre than my car. 

In an average year, my mini will do around 20,000kms, emitting roughly 920kgs of carbon, as compared to 4.3 tons for a petrol engine. I live in the country, and do not have a public transport option. While this is not no carbon, at least it is a sound reduction. Additionally, where we live in the South Island of New Zealand, electricity generation is from hydroelectric sources only: so an EV is an even more environmentally-sound option.

This calculator is quite a good idea (Transport Environment, 2022). We always hoped that our PV would be enough to power a car, and to further reduce our global footprint. It has taken a lot of time and planning to get to where we are now, including the build of our house with roof PV and solar hot water, wet back, inverters; and the purchase of an eye-wateringly expensive EV. We are now on a saving mission to replace our towing Subaru with an all wheel/4WD drive vehicle. Once a suitable one is released, that is.

We know we are lucky to live as we do. We know we are lucky to have the freedom to make these choices. And, while we may need some more PV to cover the charging of that vehicle, at least we know we are slowly, slowly reducing our impact... without being too evangelical about it.

Sam

References:

Lane, B. (2023, June 7). The die is cast: Petrol and diesel engines are dying. The electric age is inevitable. The Guardian. https://www.theguardian.com/commentisfree/2023/jun/07/petrol-diesel-engines-technology-electric-cars

Transport Environment. (2022, May 30). How clean are electric cars?. https://www.transportenvironment.org/discover/how-clean-are-electric-cars/