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For those with the money to spend, electric cars are hitting the mainstream. But the anomaly remains that if you’re using electricity, you’re still contributing to carbon emissions. So even electric cars won’t be a completely ‘clean’ option until the grid decarbonised – that is, when the UK’s electricity comes mainly from large-scale, low-carbon sources.

While the debate continues about the best way to generate all this low-carbon energy, there are some solutions available for the non-petrol-heads.

The most obvious is to do as DJ Mark Goodier and charge the car with the power of the sun. But of course those solar panels don’t come for free – unless you take up a ‘rent a roof’ offer and allow the installer to take the cash from the Feed-in Tariff. This could work, and might also lower your electricity bill.

But it won’t solve the whole problem. There’s more to greenhouse gas emissions than just CO2; generating electricity from fossil fuels causes nitrogen oxide emissions, which can result in ground-level ozone – and when this reacts with sunlight, you’ve got smog. Maybe even solar panels aren’t always your best friends.

But where there’s a problem, there is usually an intrepid researcher trying to fix it. In this case it’s those clever folk at Massachusetts Institute of Technology (MIT); and, as with many scientific discoveries, the big Eureka! brings with it a sense of ‘why didn’t we think of that before?’

Cutting the smog comes down – as so many things do – to simple timing. Specifically, the fact that charging your electric car by twilight is better than charging it by daylight. (And charging it in the dark hours is even better.)

Despite typically longer recharge times at night, when power stations are working under-capacity – which means more time for nitrogen oxide levels to rise while your car charges – much of the gas emitted at night will have dissipated by daybreak.

So there is a way to reduce emissions even while charging your car on the grid. And this brings us briefly to the subject of smart technology. All this new technology that will  co-ordinate our household energy use within the encouraging you to time your wash to auto-start at night, when a greater share of the voltage comes from off-peak low-carbon sources.

Tammy Thompson of MIT sums up the implications:

As more of the fleet switches over to electric vehicles and larger demand is placed on the electricity grid, it will become more important that we design and implement policy that will encourage charging behaviours that are positive both for air quality and grid reliability.

In plain English, she means that more and more people can adopt energy-efficient products (not just cars) – but to see the benefits, they also have to adopt the behaviour.

As the Energy Saving Trust water guru, Andrew, always says: it’s all about kit and what you do with it.