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Electric car versus hybrid – which emits less CO2?

I’ve ordered a Hyundai Ioniq Electric and whenever I bring it up or someone asks about it, the issue of Australia’s electricity grid being so full of coal rears its ugly head. The theory is that by driving an EV all I’m doing is replacing CO2 emissions from fuel, with CO2 emissions from electricity generated by coal. I want to know if this is true in Australia in 2018, so I’ve done some basic investigation to answer the question: does driving an EV result in lower CO2 emissions than a hybrid car like a Prius?

Well-to-wheel emissions

A vehicle’s CO2 emissions are more than what comes out of the tailpipe. For a hybrid, there’s the extraction, refining and distribution of petrol. That’s called “well-to-tank” emissions (i.e: an oil well to a car’s petrol tank). When combined with the emissions from the tailpipe as the petrol is combusted to make the car move, they’re called “well-to-wheel” emissions – an overview of all the CO2 emitted by the hybrid, excluding its production.

For the purposes of this comparison, I am not considering the CO2 used in the manufacture of an EV or an ICE, as various studies have shown that the vast majority of emissions from cars are a result of their use, not their manufacture. That’s not to say low CO2 manufacturing isn’t important, it’s just that over the lifetime of the car, it’s a small portion of its CO2 emissions.

The Green Vehicle Guide

The Green Vehicle Guide (GVG) takes well-to-wheel emissions into consideration with the Lifecycle Emissions from Fuel Production value in their database. This makes it easy to compare the “well-to-wheel” CO2 emissions between an EV and a Hybrid.

The GVG generates the Lifecycle Emissions from Fuel Production via data contained in the National Greenhouse Accounts Factors. This document is produced by the Department of the Environment and contains info how much CO2 is emitted by dozens of different activities including electricity generation, oil production, oil transport, oil refining and oil storage. It’s not perfect, but it’s the best we have here in Australia.

The GVG takes the values in the NGAF, mushes it all together and comes up with 2436g of CO2 per L as the “well-to-tank” figure for fuel in Australia. For CO2 generated by electricity, the GVG uses a figure of 0.9kg per kWh, also compiled from the NGAF – an average of Australia’s CO2 from electricity. The GVG publishes a spreadsheet containing the current algorithm for this at the bottom of their FAQ.

CO2 emitted per kilometer

You can visit the Green Vehicle Guide yourself and check out the cars you’re interested in, but here’s a sample of cars I chose. Toyota’s Hybrids, some small & large EVs, and some small & large ICE.

  • 2016 Toyota Prius Hybrid – 84g/km
  • 2018 Toyota Corolla Hybrid – 101g/km
  • 2018 Lexus ES 300h – 122g/km
  • 2018 BMW i3 94Ah – 122g/km
  • 2017 Renault Zoe – 120g/km
  • Tesla Model S 75kWh – 166g/km
  • 2018 VW Golf – 146g/km
  • 2017 Hyundai i30 2.0L – 212g/km
  • 2018 BMW 530i – 167g/km

It’s not a pretty sight is it? The small EVs emit less CO2 than their ICE counterparts, but the Prius and Corolla Hybrids emit far less than the EVs. When you get to the big cars, the Lexus emits less than a Model S, and the BMW 530i emits practically the same.

Why does an EV emit more CO2 than a hybrid?

If like me, you’re scratching your head and thinking how in the hell does a car using petrol emit more CO2 than a car using electricity, the answer is our grid is pathetic, and by our grid, I really mean VIC, NSW and QLD. Check out the beautiful electricityMap, where you can see in real time where our electricity comes from and how much CO2 it emits. The east coast states are all above 600g of CO2 per kWh. It’s a pathetic state of affairs. TAS & SA however, do a much better job of controlling CO2 from electricity.

Driving an EV with a 150W per KM efficiency (i.e: the Hyundai Ioniq), look at the massive difference between the east coast states and the rest of Australia using calculations from the Green Vehicle Guide’s spreadsheet CO2 per KM calculations per state:

  • NSW – 138g
  • VIC – 174g
  • QLD – 138g
  • SA – 92g
  • WA – 113g
  • TAS – 33g
  • NT – 108g

Even when using real time data from electricityMap (which is arguably more generous than the National Greenhouse Accounts Factors) instead of the Green Vehicle Guide, the Prius still has an edge:

  • NSW – 101g
  • VIC – 92g
  • QLD – 107g
  • SA – 35g
  • TAS – 3.3g

Realistically, the only states where you can be sure your EV emits fewer CO2 when charged from the grid than a Prius, is SA or TAS.

What if I purchase GreenPower?

What about GreenPower? Most energy retailers let you pay a bit more for your electricity per kWh and claim it is 100% renewable. The government even manages and certifies it. It’s a great program and I think all EV owners should pay that little extra for GreenPower electricity, as that money goes towards your energy retailer purchasing and investing in new sources of renewable energy.

But it will not immediately reduce the amount of CO2 emitted from the power you consume from the grid right now.

The electricity you’re supplied with from the grid is a mixture of fossil fuels and renewables – you cannot choose where your energy comes from via the grid. Adding GreenPower to your bill definitely helps to add renewables to the grid so everyone’s electricity gets a bit cleaner over time, and assauge some guilt, but even if everyone purchased GreenPower right now, that doesn’t magically make the whole grid clean overnight.

An EV purchased now will get cleaner, but a Hybrid will remain dirty!

The grid is getting greener very quickly right? Which would mean soon, an EV to emit less CO2 as more renewable energy is added to the grid, whilst cars with an internal combustion engine will output the same amount of CO2 for their entire lifetimes. That’s 100% correct, but the timeframe for NSW, QLD & VIC to phase out coal is quite slow.

For a Hyundai Ioniq to emit less “well-to-wheel” CO2 than a Prius, the electricity needs to come from a source that emits less than 550g of CO2 per kWh.

Going by electricityMap, which takes into consideration importing of renewables from other states (mainly SA & TAS exporting their excess to QLD, NSW & VIC), this is what each state spits out as of midday on the 3rd of December, 2018:

  • VIC – 617g/kwh
  • NSW – 653g/kwh
  • QLD – 693g/kwh
  • SA – 208g/kwh
  • TAS – 22g/kWh

SA & TAS are already below the 550g/kWh mark. VIC, NSW & QLD need to reduce their coal production by around 10% to 20% to meet the 550g/kWh mark. When will that happen?

It seems likely the magic 550g of CO2 per kWh mark will hit VIC 2020. 2025 seems more likely for QLD & NSW however.

What have we learned?

A Toyota Prius emits less CO2 per KM than an electric car in VIC, NSW & QLD, even when taking into consideration “well-to-wheel” emissions from the production & transport of petrol.

The reason for this is that the grid in QLD, VIC & NSW is so heavily powered by coal. EV owners in TAS & SA will emit less CO2 than any Hyrbid thanks to their clean power grid.

GreenPower helps your retailer purchase and invest more renewables for the grid, lowering CO2 emissions over time, but doesn’t change the CO2 emissions of the electricity you receive now.

The grid is getting cleaner every day. Right now in TAS & SA, an EV is cleanest. By 2020 an EV purchased now will emit less CO2 than a hybrid in VIC and by 2023-2025, it will be cleaner than a Hybrid in all of Australia.

If you have rooftop solar and can power your car during the day using a Zappi charger, this is the best way to ensure your EV is truly zero emissions.

For the full environmental benefit of EVs to be realised in Australia, we need our politicans to stop sucking at the coal teat and move to 100% renewables as soon as possible.

So why own an EV at all?!

Let’s be clear – the problem when it comes to minimising CO2 emissions is our grid, not electric cars themselves. Overseas, where the electricity is cleaner, EVs are far less polluting than a hybrid vehicle. It’s Australia, and NSW, QLD and VIC in particular, where the full environmental potential of an EV cannot be realised.

Does that mean nobody should buy an EV? Not at all! There are other reasons to enjoy an EV like a superior driving experience, low running costs and true zero emissions by charging from domestic rooftop solar. Supporting EVs in Australia needs to go hand in hand with harassing politicians to implement 100% renewable electricity as soon as possible!

Anthony also produces The Sizzle - a daily email newsletter covering all aspects of technology with an Australian point of view.