Wind Power Farm

The grid is (getting) greener & so are EVs

Posted by Roseanne: Jan 22, 2020 5 min read

Our Head of Insights, James McKemey, explores the relationship between BEVs and the UK’s grid carbon intensity. How does a Toyota Yaris hybridisation really compare with a full BEV?

A lot of people have a lot of opinions on how green EVs are and scepticism abounds when there is still fossil fuel generation on the system.

But, here at Pod Point, we like to do the sums, and there is now an abundance of really good, easily accessible data available online from which to construct definitive answers.

How green does your garden grid grow?

Firstly, take a look at the Grid Carbon Intensity tool from National Grid Electricity System Operator (ESO).

This allows you to export monthly grid carbon intensity data, and there is now complete data available for the last two calendar years. Being extraordinarily fun at parties, I have plotted all of this data into Google Sheets and concluded the following:

Average UK grid carbon intensity:

  • 2018 - 247.99 g/kWh.
  • 2019 - 212.71 g/kWh.

That's a 14% reduction in a single year! This is broadly due to continued significant reduction in coal-fired generation and significant continued increase in renewable generation, particularly wind power.

The ESO have helpfully made this graphic that shows this is a long term trend that, with turbine installations continuing, sees no sign of stopping.

This means that electrifying stuff (like cars) is a really good idea!

As the grid greens each year, so do our electric cars. Without their drivers having to do anything at all.

Take that data and stick it up compare it to your tailpipe

Total Emissions Comparison

To put this into car context, let’s compare BEV emissions to an efficient alternative. And while you can do wonderful things by charging via your green tariffs, or via your own micro-generation, we’ll concern ourselves with those just plugging into the average UK mains.

I’m going to use a fair theoretical “typical” BEV with an average efficiency of 300Wh/mile. This is equivalent to something like a frugal new Tesla Model S, or more sporty Model 3, perhaps the new Polestar 2, but definitely not a highly efficient small BEV.

Our efficient alternative here is a new Toyota Yaris 1.5L hybrid, a very small and efficient hybrid internal combustion engine car.

Car  Emissions g(CO2)/km 
300 Wh/mile BEV 39.9
Toyota Yaris 1.5L Hybrid 87 (NEDC*)

So fairly average efficiency BEV’s are now about twice as carbon-efficient as the most eco-friendly internal combustion engine vehicles… Even if you obey the convention of pretending petrol just appears in cars’ tanks and there is no carbon footprint associated with its extraction, processing, refinement, shipping and pumping. And if you believe that, you may be in the market for a bridge.

Emissions Reduction Comparison

Now let’s see what the reduction in carbon intensity has done for the BEV when compared to using hybridisation as an attempt to make cars greener.

By undertaking the highly complex engineering project of hybridising the Yaris, Toyota have taken its emissions from 113g/km (1.5L petrol) to 87g/km (1.5L petrol-hybrid) according to the NEDC*. This is a 26g/km (23%) total reduction in its carbon intensity.

By using the ESO data, in less than 5 years our 300Wh/mile average UK BEVs have saved >26g/km (~50%) by... er... Doing. Nothing. At. All.

We note that the accuracy of the Not Even Damn Close New European Driving Cycle (NEDC) assessment methodology has been rather discredited, but these are the figures we have available. *

But, what about the whatabattery?

Okay, there are likely to be additional emissions in the generation supply chain, but we can be confident they are lower than those in energy-intensive petrol production (and we didn’t count those either). And of course, BEVs must be manufactured, and indeed there is, today, a higher carbon footprint for the manufacture of a BEV than for a conventional ICE car (though there’s progress here, e.g. VW have announced carbon-neutral production of their upcoming ID range!). Like the emissions involved in the petrol supply chain, these are hard to assess, however, the boys and girls at MIT have had a pop. I strongly recommend using their whole life cost tracker here:

For example, you can put in 212.71g/km (or 210 as the nearest approximation on the slider) as your grid average in the "Customise" tab and you'll get to something like the graph below - pretty darn good eh? Flexing the manufacturing carbon emissions up and down makes some difference to the whole life emissions, but doesn’t make any impact on the BEVs’ supremacy.

There really is no contest here. And it’ll be even more stark next year. And the year after. And the year after… etc. The internal combustion engine, even in relatively frugal hybrid form, has lost the race in the UK. It is simply not worth continuing to develop it. It’s time we all move as fast as possible to EVs. The good news is they are FAR BETTER CARS AS WELL!

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