nekomatic wrote: ↑
Thu Sep 29, 2022 10:48 am
This is your periodic reminder that if you want to spend some money on being green, getting solar panels or investing in renewable energy schemes will almost certainly abate more carbon per £, and probably give you a better RoI, than buying an electric car. IANAFI etc.
Some back of envelope.
Typical EV does about 3 miles per kWh, probably usually a bit more, but call it that for electricity losses in charging. So you are talking about 2700 kWh per year consumption for 8000 miles. The av carbon intensity of UK electricity grid is now down to 180 gCO2/kWh. So you use just short of 500kg of CO2 in your electric car.
Assuming you aren't getting an SUV or something stupid, you might get 12miles per litre from a modern car. So about call it 667 litres of fuel. At 2.4kgCO2/litre that's about 1600 kg of CO2 for your car.
So you are saving perhaps of the order of 1100kg of CO2 per year by having a BEV, at current grid intensity. DId a quick literature search, and recent articles suggests an EV typically emits about 1/3 of the CO2 per km of a liquid fuelled car, so I'm around the right order. I ought to make a deduction for manufacturing emissions, which are larger if your battery is Asian.
If you have a 4.5kW array of solar on your house, which I think is about average then at UK average 11% capacity factor you will get generate about 4300 kWh of electricity. So that displaces about 800 kg of CO2 at the current carbon intensity of the grid. My supplier is quoting about £8,000 for a standard installation like that, but it won't be standard in my case.
So if you can buy a satisfactory BEV for about £8000 more than a conventional car, it isn't obvious to me that a solar array is a much better investment, it's somewhere thereabouts, in terms of carbon abatement per £. Though if you only pay £8000 more than an equivalent combustion car, you are probably only getting one of those many BEVs on the market which only has a range of 200km, which is a joke. Or something small. And then if your alternative is a 2nd hand car, the difference increases.