Analysis: Just how green are electric vehicles?

The story caused an expected stir in Belgium with arguments about Ernst’s calculations, which were variously adjusted to around 350,000km or, in the case of claims from professors at the Delft University of Technology, the calculation is ‘just’ 80,000km driving before the vehicle breaks even on its larger manufacturing energy footprint. 

It’s not the first time that EV battery manufacturing has been called into question. A year ago, the International Council on Clean Transportation released an in-depth report on the same issue. It summarised 10 different studies into battery manufacturing globally, all of which attempted to calculate the CO2 released. 

The results ranged from 50kg CO2/kWh to 200kg CO2/ kWh and even higher. The ICCT used a central estimate of 175kg and calculated that battery production would add 35g CO2/km to the lifetime efficiency of an electric car, assuming the battery lasted 150,000km (93,200 miles). 

The ICCT report also compared a Nissan Leaf carrying a 30kWh battery with a Peugeot 208 1.6 BlueHDi, and concluded that the Nissan has a relatively modest 30% efficiency advantage in day-to-day use. 

The IVL Swedish Environmental Research Institute came to a similar conclusion in 2017, stating that an EV with a big 100kWh battery – manufactured on a grid that was between 50-70% fossil fuel – has emitted between 15 and 20 tonnes of CO2 before it has turned a wheel. 

The IVL recommended that drivers should not buy an EV with a large battery and that it was important that future battery manufacturing was achieved with as much renewable energy as possible. 

Audi’s newly rebuilt facility near Brussels has gone down this route for its production of the new Audi E-tron. The factory has 37,000 square metres of solar panels, said to provide 95% of its electricity, and it uses biogas to heat the plant. The E-tron’s battery is also built on site, helping to drive down its embedded levels of CO2. 

Clearly, while EVs have a huge advantage in terms of local pollution, the whole manufacturing cycle is surprisingly energy-intensive and the day-to-day energy efficiency is not as impressive as it should be on the typical European grid. 

If building EVs wasn’t financially risky enough for car makers, demands for factories to run mostly on renewables adds significantly to the cost.

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