Carbon Emissions EV vs Efficient Petrol or Diesel
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From: Ben Tomkinson
Dear Climate Change Commission,
I have been looking into the total carbon footprint of EVs over a ten year period (the average lifespan of the batteries is 8-10 years) for an average, medium sized EV. I have calculated the total emissions, factoring in the mining and production emissions, and then what on average the total carbon emissions it would emit over a 10 year period, travelling 50,000km per year, and have compared my findings to the following
1- A petrol powered Suzuki swift which has a fuel efficiency of 4.6l/100km
2- A Renault traffic diesel van which has an efficiency of 6.2l/100km
I have found using the figures given, the petrol car would consume 46 litres of fuel per 1000km, while the diesel car would consume 62 litres. Assuming an average carbon content of 2.3 kg CO2 per litre of petrol and 2.6 kg CO2 per litre of diesel, the petrol car would emit approximately 1060 kg of CO2 per 1000 km, while the diesel car would emit around 1612 kg.
Now for the EV, If the power grid supplying the electricity for the electric vehicle was 80% hydro and 20% coal, the carbon intensity of the electricity would be somewhere between that of hydroelectricity and coal-generated electricity. According to the International Energy Agency, the global average carbon intensity of electricity generation in 2020 was 475 grams of CO2 per kWh.
Assuming the same medium-sized electric vehicle with a battery capacity of 60 kWh and driving 1000 km, it would require approximately 200 kWh of electricity. If 80% of the electricity was from hydro and 20% was from coal, the carbon intensity of the electricity would be approximately 124 grams of CO2 per kWh (0.8 x 80% + 1 x 20% = 0.84 kg CO2 / 6.8 kWh = 124 g CO2 per kWh).
Therefore, the emissions associated with recharging the vehicle would be approximately 24.8 kg of CO2 per 1000 km driven, or between 248 and 304 tonnes of CO2 emissions over 10 years, when combined with the battery production emissions of between 9 and 12 tonnes of CO2.
Even with an 80% hydroelectric grid, the electric vehicle would still emit more CO2 than the petrol and diesel cars, due to the emissions associated with battery production.
My question based on my findings are,
1- Why are efficient vehicles such as the above mentioned not included in the clean car rebate given their total emissions are less than that of an EV?
2- Why are we not promoting the use of such efficient petrol or diesel cars over the use of less efficient EVs that have an overall larger carbon footprint, and the fact that we also need to factor in how to dispose of these batteries?
I look forward to hearing your response.
Climate Change Commission
Kia ora Ben,
The purpose of this email is to acknowledge receipt of your email requesting information relating to electric vehicles. The request was received 23 March 2023 and the latest you can expect to hear from us is 24 April 2022. This request has been given the reference number 2023-006. Please use this reference if making any enquiries about this request.
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Climate Change Commission
Tēnā koe Ben
I refer to your email below, requesting the following information under
the Official Information Act 1982 (the Act):
“My question based on my findings are,
Why are efficient vehicles such as the above mentioned not included in the
clean car rebate given their total emissions are less than that of an EV?
Why are we not promoting the use of such efficient petrol or diesel cars
over the use of less efficient EVs that have an overall larger carbon
footprint, and the fact that we also need to factor in how to dispose of
The details of your request fall within the responsibilities of the
Minister of Transport. While it would have been necessary under section 14
of the Act to transfer your request, as the information you have requested
is more closely connected to and held by another agency, we are aware that
you have already requested the same information from the Minister of
Transport. For this reason, we have not considered it necessary to
transfer your request as the Minister of Transport has confirmed receipt
of your request already.
You may also be interested in the following report on the emissions of
Electric Vehicles in the Aotearoa New Zealand context:
o Life Cycle Assessment of Electric Vehicles | EECA
In addition, you may find this Transpower dashboard interesting to
explore, available at: em6. This dashboard captures Aotearoa New
Zealand's carbon impacts from electricity and level of renewables.
We hope providing this extra information has been helpful, however, under
section 28(3) of the Act you have the right to seek an investigation and
review of this letter by the Office of the Ombudsman. The relevant details
can be found on their website at: www.ombudsman.parliament.nz
Please note that the Commission has a policy of proactive release of
responses to requests made under the Act to help others have access to
more information. As a result, this letter will shortly be published on
our website with your name and contact details redacted to protect your
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