Using more renewable energy—for electricity generation and other energy services—and electrifying our transportation system are highlighted as priority areas for the path to reach the CCC’s recommended emissions budgets and the 2050 target. But what may the consequences be for our society’s impacts?
Let’s consider increasing the number of electric vehicles (EVs) on our roads.
If the environmental metric considered is only the total carbon dioxide equivalent (CO2e) emissions—or greenhouse gases—over the lifetime of the vehicle, and the grid is largely based on renewables to charge the vehicles—as is fortunately the case in New Zealand—then EVs are a better option than internal combustion engine vehicles (ICEVs).
This was the conclusion of a paper published in the June 2020 issue of Nature Sustainability, with domestic estimates that EVs are seven to ten times more CO2e efficient than ICEVs over their full lifetime when using 100 percent carboNZero Certified Electricity. And, of course, there are local air pollution benefits with EVs.
However, recent academic research also concludes that, if resource use and other environmental impact metrics, such as freshwater contamination, are considered, then EVs perform worse than ICEVs. Of particular concern are the environmental burdens offshore and upstream from the manufacturing, and with the end-of-life phase, of the vehicles.
EVs, generally, have more complicated value chains, with a heavier reliance on key mineral resources. Lithium, manganese, copper, nickel, and cobalt, required in different quantities depending on the specific characteristics of the batteries, result in the higher environmental impacts compared with ICEVs.
Additional social, ethical, and legal aspects are also associated with the resource use. Cobalt, especially, remains problematic to the battery, and EV, industry, with human rights issues associated with its mining, which mainly occurs in the Democratic Republic of Congo (DRC). This is, of course, not entirely new to us, since our modern lives, with ever increasing consumer electronics, are entirely dependent on questionable ethical mineral resources, such as coltan, also mainly mined in the DRC.
The batteries also have to be replaced about every ten years, again depending on the specific batteries. Unlike with the usual consumer electronics, these retired batteries typically will still have between 70 and 80 percent of their initial capacity. Once they have lost up to 30 percent of their initial capacity, they don’t satisfy the range and performance requirements for an EV, but they still have sufficient capacity for less-demanding applications; for example, they can be used for stationary applications to fulfil on- and off-grid storage requirements. This is referred to as their ‘second-life’.
However, it does mean we need the necessary capacity to repurpose the batteries for those applications. Also, there comes a time when their capacities are simply inadequate, and they need to be recycled to recover the materials; in theory, to supply back to the manufacturing phase—what is referred to as the circular economy.
New Zealand has yet to enact specific legislation to address these issues, and while our domestic uptake of EVs increases gradually, to address our CCC budgets, we won’t, in all likelihood, have the economies of scale in the near term to effectively handle the batteries, other than to export them to large, centralised recycling centres.
This is just one example of why we require a system-wide perspective. Yes, we need to do our part with the climate change challenge, but society needs to realise we rarely have a total life cycle perspective—in particular with the resource extraction requirements and the end-of-life phases of current and alternative technologies—when we transition to a new state.
While we undertake the necessary actions to meet our targets, we need to put in place more transparent supply chains—to ensure ethical and sustainability best practices—and improve the sustainability of the end-of-life phases.
By Professor Alan Brent, Chair in Sustainable Energy Systems, School of Engineering and Computer Science