• #EV tariffs
  • Aug 04, 2021

Charging an EV at home is usually the moment that you stop and notice the energy you use every day. It’s not just because your home use (and bills) go up by around 50%. The big change is that, all of a sudden, you have the chance to interact with your energy, to use it or even avoid using it in line with your environmental passions and cost-saving instincts. Suddenly, energy isn’t so boring anymore.

That’s right, a simple tariff switch can have a secret super power as you maximise the positive carbon impact. And this is what probably led you to want an EV in the first place. The big difference for people looking to switch energy in 2022 will be the arrival of ‘smart’ or ‘managed’ charging to the growing array of EV-friendly tariffs.

The key to supporting green energy is creating flexible demand.

If you’ve long been signed up to a ‘green’ tariff, is there anything more you can do? Well, yes there is. The challenge for green power is that our routines are surprisingly similar - we get up, travel and cook at the same time. We create predictable peaks and troughs in demand. Renewable power, like wind and sun, doesn’t turn up at the right moments to supply these routine demands. The power you actually use on a green tariff may be from fossil sources, which your supplier matches with green energy used somewhere else at another time.

The key to supporting green energy is creating flexible demand. Here’s where EVs are a brilliant help, acting as power stores on wheels. Charging is a relatively moveable demand, as your car is often stationary for many hours at a time, especially overnight. Being smart about when we charge our EVs can help spread the demand across each 24-hour period, reducing the need for high peak power generation.

EV tariffs were the first answer to this. They gave us fixed overnight windows with cheaper energy. As the number of EVs increases, EV tariffs are no longer the complete answer. A fixed off-peak window does not always coincide with the cheapest and greenest energy. Now is time for a smart fix.

Step in smart charging, also called intelligent or managed charging. Electric cars connected to the grid with smart charging support green energy sources - the car pauses or shifts its charging to mimic the capacity of the grid. It will still be ready when you need it. Without smart or managed charging, EVs could become a burden on the grid, requiring carbon-intensive generation or expensive upgrades to the physical supply network.

Carbon cost of EV charging
You can squash cost and carbon by shifting your charging from average grid to greener off-peak. Figures for an EV driving 7,400 miles per year

What is managed charging?

Managed charging – also called intelligent or smart charging — allows a utility or third-party to remotely control vehicle charging by turning it up, down, or even off to better correspond to the needs of the grid.

How does managed charging work?

Your utility will connect either directly to your car (Tesla does this well) or, more likely, to your charging equipment through an app. You set the time you need your car to be ready, and the minimum charge you’ll need. Then, based on the supply of green energy, they’ll charge your car when it’s cheapest for you, and greenest for the grid across all the hours you’re plugged in.

Why is managed smart charging better than an EV tariff?

The popularity of the EV tariff Octopus Go, with an off-peak window of 12.30-04.30am, actually created its own mini-peak as thousands of EVs all switched on to start their charging at exactly 12.30am. This kind of new night peak is far from ideal, and the whole point of off-peak charging is to shift demand outside of a peak and bring it into line with low congestion moments on the grid.

In response to this Octopus staggered the start times of its off-peak tariff with a new tariff called Go Faster. And as the number of EV tariffs increases, the off-peak windows will become more diverse.

What's the best tariff for me?

Compare EV tariffs

But, as well as moving more demand overnight, there is also the need for small demand ‘shimmies’. These may be seconds or minutes when there is pressure on the grid. All that is needed is a short pause in your charging, to add to the demand response. This is the kind of flexibility that managed charging can provide.

It’s worth adding that the other answer to static EV tariffs is dynamic pricing, like Octopus Energy’s Agile tariff, that uses a sort of day-ahead 'congestion charging'. These tariffs mean buying energy like we now buy air tickets - we expect to pay more on a popular date compared to a date when the place is half empty. At times when we are all using the grid prices go up, and when there's lots of energy, prices will fall.

How much will I pay for smart charging?

Ovo are preparing to launch Drive Anytime this Autumn. This tariff means you’ll pay only 6p/kWh to power your car whenever you want, It’s currently the only “type of use” energy plan in the UK that offers electric vehicle (EV) owners a separate rate for their car and home, the positive news is you can charge your car whatever time of day you wish, but the downside is you’ll keep paying your current rates for your home energy. It suits any household where routines are completely fluid and flexibility really is king.

New to the market, but as a trial or beta version, Intelligent Octopus gives users a low price night rate for their EV and home energy use of 5p/kWh between 11:30pm and 5:30am. Outside of these hours customers’ have a unit rate that varies by region and a daily standing charge, both are similar to the competitive rates it offers on its Go tariff.

Intelligent Octopus may end up scheduling your charging outside this off-peak window, but you’ll pay the same night rate. And if you need to charge more urgently, you can trigger a bump charge through the special app at your normal daytime rate.

So, how much could I save?

Average unit price in the market (among the top ten suppliers) is anything up from 16p per kWh, which is the price you’ll probably be paying in cheaper regions like London. Assuming an EV uses 2,000kWh per year charging at home (that equates to something like 8,000 miles), Ovo estimates that you’ll spend £120 on OVO’s Drive Anytime preferential rate and £320 on a regular tariff – a 63% saving on your charging.

Octopus, meanwhile, estimate a user who is already on an off-peak tariff will save a further £100 by switching to it’s intelligent tariff. This assumes 15,000 miles driven per year with 100% of charging in the Intelligent Octopus window vs. 80% of charging in the Go window, and a day rate of 15.49p/kWh. This also includes savings in underlying household consumption for a longer night window.

What technology will I need for smart charging?

To be eligible to sign up for Ovo’s Drive Anytime, which will be rolling out nationwide this autumn, you must be using an OVO smart charger to charge your EV. Ovo haven’t released details yet, but it could be possible for household’s without a smart meter to benefit from this tariff, as the clever bit comes from the charger itself.

Octopus Intelligent Octopus currently works with Tesla cars or Wallbox Pulsar Plus chargers. They are working to add more chargers. You’ll also need a smart meter. During early access, the app is only available for iPhones with iOS 14 or higher but an Android release is on the cards.

How much will charging lower my carbon footprint per mile?

On average, each kWh of grid carbon has just over 200g associated with it. That means 50g of carbon is produced for every mile you drive. When you charge, the carbon will vary depending on the other demand on the system and the supply from intermittent generation like wind turbines (or solar during the day). The lowest grid carbon registered in 2020 was 42g, possibly lower than we’ll see for some time yet as it reflects how the UK energy demand dried up during lockdown in May. The target for 2030 is 100g per kWh.

If you drive steadily through the year, roughly the average number of miles, you’re likely to do 20 miles per day. The chances are that smart charging can more than half the carbon footprint of an average car. Instead of 370kg of carbon, your car will be responsible for less than 185kg. In reality it could be lower, as you’ll only need to charge up over the best five or six hours carbon-intensity speaking through an entire week.

What if I can't get a smart meter?

Sadly, most of these tariffs require you to have a smart meter. Partly this is policy - utilities have targets to meet in terms of smart meter installations. But although certain apps can bypass the need for a smart meter by measuring car charging in kWh, the system is not foolproof, and all other household use can’t be billed at the lower rate.

There’s lot going on with energy, both these tariffs are currently in beta or trial, but we will be hearing more about managed charging over the next year or two. The lower running costs from EVs are one of their biggest selling points. And of all the lower costs associated with an EV, the biggest saving comes from how it is ‘fuelled’. It's not just money-saving for the switcher - the better we are as consumers at using electricity when demand is otherwise low, the more efficient and low-cost our grid can become for everyone.

Can all our electric cars mean more renewables?

Smart charging is one form of demand side response (DSR). This idea of demand coming to meet supply means more renewable power can be used directly. Excess renewable energy is often diverted into storage and used later, with losses of around 25%. Some times spare energy is simply dumped as it can’t be transmitted or stored. So using more energy makes renewables more attractive investments, which in turn leads to more renewables being installed and providing more of their cheaper power. Cheaper power will in turn make other necessary things happen, like electric heating in our homes becoming cost-effective, enabling a further chunk of carbon to be removed from our lifestyles.

This chain reaction is why we are very excited by the potential for EVs to help spread the word about flexible tariffs that pass on the secret signals contained within the wholesale price of energy.

Sign up for EV and clean energy news