Can an electric car drive a greener mile?

Can an electric car drive a greener mile?

Last year, after driving our children home from a school strike for climate event in our old diesel, we stopped thinking about an electric car as something we’d do in the future. But, like carbon offsetting a flight, we were expecting to pay more to lower our carbon footprint…

Choosing between a small (but growing) number of EVs wasn’t straightforward. But the driving experience and everything about ‘going electric’ was exciting and full of possibility. We were hooked immediately – our carbon footprint was lower and we were paying less to drive each mile.

Selecting an electric car is a different experience from choosing a conventional car. EVs bring a whole new set of considerations and options. Take, for instance, battery size: go too small and you could worry that you’d be spending too long to stop and charge; but too large and there’s probably a much higher price tag and unnecessary weight. Running costs and carbon footprint might also be much more important to an EV buyer, but these can vary widely even for the same model, depending on when and where you drive it and charge it.

Remote living and range

When we started looking for our first green car, we assumed that living in a rural spot with few charging points would rule out a full electric. A hybrid seemed like a sensible choice. However, the hybrids we looked at only offered a 30 mile electric range. It didn’t take long for us to realise this meant a significant number of miles would be fuelled by petrol – and, as the battery weight makes every petrol mile less efficient, the mpg would be lower on top of that. Definitely less bang for our buck, climate-wise.

Calculations of total ownership costs show they don’t manage to deliver on financial savings either. With both a petrol engine and a motor, maintenance costs are higher, and the proportion of cheaper electric miles is limited.

If you are looking at full electric vehicles (BEVs), range is probably your biggest EV concern. Yet, as ranges of new EV models get larger each year, it is possible many of us will end up driving a far heavier (and more expensive) car than our journeys might warrant. The average car trip in the UK is only 8.4 miles, and only 4% of all UK journeys are over 200 miles. This matters to your carbon footprint as, in general, the larger the battery pack and the more luxurious (and heavy) the model, the longer the time to pay back the car’s embodied carbon.

Paying more to go clean?

Before our EV arrived, we were still thinking like diesel drivers, and hadn’t even considered how much easier it would be to “fill-up” at home. Maybe this is because much of the talk around EVs focuses on improving the public charging networks, which doesn’t reflect the reality that over 90% of charging is done at home.

Yes, our energy bill did increase to start with, but this charging also brings a further opportunity to make the kind of changes that might have led you to choose an EV in the first place.

Because EVs are often fuelled overnight at your home, electric cars are naturally using energy when demand is otherwise low. Low demand usually means lower wholesale grid prices. EV drivers can choose between a growing number of tariffs with cheaper overnight hours. By switching to off-peak charging, our cars become greener and each mile is cheaper.

Delaying our charging until the other side of the evening peak means less carbon-intensive electricity generation. As well as overnight pricing to delay charging, with a dynamic tariff EVs can also plug in to mop up any surplus on the grid – a sunny weekend or a windy night – and in doing so they further support renewable generation.

Save with smart ToU tariffs

We got quite excited when we discovered these ‘smart’ electricity tariffs with cheaper off-peak charging. There is nothing greener (or cheaper) than charging your car using electricity created by a surplus of renewable energy on the grid. We actually pay less for home energy now than we did before getting an EV.

You won’t find these tariffs on the usual comparison sites, and they aren’t always well promoted by the utilities that offer them. They are often bundled with other services (such as membership of roadside charging networks) and each operates slightly different off-peak hours. This all means that choosing the best Time of Use (ToU) tariffs can feel like guess work. Yet even small differences in unit rates and timings mean our bills could be up to £400 per year higher if you don’t get a good fit for your charging and home use patterns.

Good news for home solar

Better still, you’re able to call on solar power. Of course it feels good to fill your tank with clean overnight electrons, but daytime solar lowers the running cost for each mile. EV ownership can dramatically improve the payback from solar panels if they can use energy over the day, or sometimes even if they store it in a home battery for use later.

With an EV, the payback can be as little as 7 to 8 years – a big improvement on the lengthy 20+ years calculated for a new, unsubsidised system to pay back in the UK.

EVs support a greener grid

EVs can empower the individual to become more self-sufficient – through solar and home batteries. They also offer the consumer the ability to become actively involved in the transition to a green and cleaner future – through shifting demand off peak. And their impact won’t stop there. With Vehicle-to-Grid (V2G), EV batteries offer a ‘reservoir’ for energy. They could be revolutionary to the way electricity is managed on the national grid. With a network of plugged-in EVs that can deliver back power at peak times, the promise of a fully renewable grid glimmers on the horizon.

A greener grid supports greener EVs

It works both ways. As more and more of us switch to an EV, the grid can get greener – and the emissions associated with all plugin cars will fall further. As the electricity mix gets cleaner, the carbon payback of your EV and its battery gets shorter. The environmental credentials of your electric vehicle will grow stronger even after it leaves the factory. In just four years’ time, the changing grid mix means lifetime emissions of a Nissan Leaf will fall to less than 30% of an efficient ICE car.

Future cars and future homes

It wasn’t part of the plan that we saved money too. But with an EV that fitted our driving, combined with a tariff switch to match our use patterns, the lower costs per mile and lower home energy costs were startling.

We are driving close to the UK average 7,800 miles in a small family car and charging overnight, which we calculated would be saving us around £1,000 per year in running costs compared to a petrol car doing an average 12p/mile.

An EV offers much more than an enhanced driving experience. Changing our car meant changing our relationship with energy too. But like us, many people start driving an EV before they realise the potential for making it cleaner and cheaper. With the right fit of EV and renewable energy you can maximise both carbon and financial savings. Maybe the 12 million UK drivers keen to switch to an electric car might start driving their future car a little sooner if they had at their fingertips figures for how affordable an EV is right now.

About the author

Laura Thomson co-founded Power My EV with renewables engineer husband Mat after buying an electric car in 2019. A quick, free online assessment matches the way you use a car to an EV and calculates the best home energy to power it cheaper and cleaner.

Laura Thomson

Written by

Laura Thomson

September 16, 2020