• EV tariffs
  • Sep 24, 2021

Many tariffs on the market like to shout about their green credentials, none more so than the suppliers of EV tariffs. All the EV tariffs currently on the market make claims to be ‘100% green’ or 100% renewable. This sounds like the energy sourced must all come from wind, solar, nuclear or other forms of generation classed as renewable by the UK government.

However, moving to a green tariff it doesn’t necessarily mean that your electricity supplier will buy more renewable energy. Instead, they could just divert more of the green energy they source to your green tariff, and boost the amount of fossil fuels in their standard tariffs.

That’s why when choosing a ‘green tariff’, it’s more important to look at the supplier’s green credentials than at the green claims of the tariff alone.

How can I charge my car with green energy?

First up, it’s not technically possible for renewable power to be directed to your home unless you have a direct line – like solar panels on your roof, for example. Apart from that, no matter what tariff you choose, the electricity you use at home is the same as your neighbours.

Doesn’t this mean that you could just opt for any old supplier? Not at all. Your choice of tariff can still influence how fast we expand the amount of renewable generation in the UK.

Is my energy supplier really green?

Amongst EV tariffs there are a variety of ‘shades of green’. Although all EV tariffs make renewable claims, by delving a bit deeper we can see how green they really are.

Some utilities actually own renewable generation, such as solar parks or wind farms. Other suppliers have parent companies which generate or own renewable generation. Still more suppliers buy some or all of the electricity they sell directly from generators, using contracts called Power Purchase Agreements (PPAs). These provide a source of income to renewable generators that helps make them financially viable.

Meanwhile, it is also possible for suppliers buy from the wholesale market and cover this energy with certificates, called REGOs. They buy only what they need to match what their ‘green’ customers have used to renewable electricity already put into the system elsewhere. This means your ‘green’ energy provider might not be buying green energy at all, just the certificates.

According to Which?, it can cost suppliers as little as £1.55 per year to say that your year’s electricity supply is renewable. The problem is that’s not enough to support further investment in more renewable energy.

Who sells the greenest EV tariffs?

Only a small minority of suppliers actually own renewable generation such as solar parks or wind farms. Currently these two suppliers can claim to be the closest to actual green generation:

  • Good Energy sets up contracts with small generators (like farmers with a field of solar panels). Good Energy uses forecasting to predict exactly how much power its generators will be feeding into the grid to make sure it has enough to meet customers’ use.
  • Green Energy UK stands out for its green gas. Unlike others, who offset their gas emissions, green energy UK produces all of the gas it provides to its customers by anaerobic digestion.

What’s the best tariff for me?

Compare EV tariffs

Who else generates green EV energy?

The main utilities active in the EV tariff (time-of-use) marketplace today are Octopus Energy, EDF and Ovo. Here’s how they fair:

  • Octopus Energy supply 100% renewable energy only. A relative newcomer (they launched in 2016), Octopus now supply over 2 million UK homes with an high customer satisfaction. They buy a portion of energy directly from UK green generators, from community generators and over 300 renewable sites managed by Octopus Energy Generation – Europe’s biggest investor in solar energy. Octopus also buy REGO certificates to set against the portion of energy they buy on the open market.
  • EDF’s EV tariffs are backed with 100% zero carbon renewable electricity. EDF’s website states that the GoElectric tariff comes from renewable sources like wind, solar, biomass, tidal and hydroelectric. The fuel mix for EDF overall is 66.6% nuclear and 20% renewables.
  • Ovo took a step closer to the energy they supply with the announcement of two PPAs (power purchase agreements) early in 2021. These are 100% of the power from Barrow Offshore Wind Farm and Crystal Rig Wind Farm in Scotland. All other claims of renewable electricity are matched by REGOs. Ovo’s definitely heading in the right direction with these new PPAs.
Supplier OVO EDF British Gas Scottish Power Octopus Energy National Average
Energy Source % % % % % %
Coal 0.00% 3.50% 0 4 3.90%
Natural gas 48.10% 9.30% 0.00% 50.00% 39.40%
Nuclear 0.00% 66.60% 24.00% 6.00% 16.60%
Renewables 51.90% 20.50% 76.00% 36.00% 100.00% 37.90%
Other fuels 0.00% 0.10% 4.00% 2.20%
CO2 g/kWh 178 70 198
Radioactive g/kWh 0 0.0047 0.0012

What’s wrong with green certificates (REGOs)?

It only costs suppliers a relatively small amount to purchase one REGO. The total cost to a supplier to claim that a domestic electricity tariff is green by backing it with REGOs is around £1.50 per year. The result does nothing to support the creation of new renewable projects.

An investigation by The Times in 2020 found that REGO certificates could be purchased even cheaper than this – at just 30p per megawatt hour of electricity consumed. With the average UK household typically consuming 3.1 MWh of electricity per year, energy suppliers can pay just 93p per customer to claim that a full year of green energy has been used.

The Times investigation showed that 20% of the energy produced from suppliers of REGO certificates are coming from Biofuels and the burning of wood fuel pellets.

What else can I do to support green energy?

September’s gas supply crunch exposed the vulnerability of the energy market to price. For renewables the price is fixed and predictable, the vulnerability is intermittency. But the answer to this (or part of it) could soon be sitting on our driveways – the electric car. Electric cars will allow us to become more flexible consumers, able to mop up excess green energy on the grid and avoid contributing to carbon-intensive demand peaks.

The average carbon intensity of energy that arrives at our sockets from the grid in 2020 was 217g/kWh. By 2035 it is predicted to fall as low as 41g per kWh. This average hides huge variations – both between the seasons and also different times of the day. You can check the electricity info website to see the current levels of grid carbon or download National Grid’s ESO app.

The UK’s typical mix of electricity sources over 24 hours

As a rule, avoid charging your EV in the morning after 7am and between about 4pm and 10pm. Excluding these times when you can will lower the grid carbon of the electrons you are using. On the whole, electricity that comes overnight through the grid is 25% more likely to come from renewable sources.

If you have an EV tariff, you’re probably already limiting your charging to the cheaper, greener small hours to conveniently charge while you sleep. If you want green energy, but can’t always charge overnight a managed tariff may be a great alternative.

To keep our energy getting cleaner in the longer term, keep an eye on the fuel mix of the supplier you’re on and how connected they are to the green energy they supply. Your switch counts!

Read more: What else can I do to increase the efficiency of driving my EV

We can reduce our energy consumption at home too, for the good of the planet as well as our pockets. Improving the insulation in your loft and draught-proofing your home can all help keep your energy bills down.