EV charging infrastructure: Minimising the environmental impact

EVs are a green technology. EV chargers should be too.

 

EVs don’t produce emissions whilst being driven, but they are not emissions-free. Some emissions are generated in order to manufacture them, power them, and produce the infrastructure to charge them.

 

Fortunately, in countries like Britain, where much energy generation comes from renewables, EVs produce far less emissions per km than internal combustion engine (ICE) equivalents. In these markets it then takes 2-4 years to offset battery manufacture emissions, known as ‘payback’. Over time the electricity mix gets cleaner and payback falls, whereas ICE vehicles offer little room for efficiency improvements.

 

Considering the benefits of an EV driving nation, rolling out the enabling charging infrastructure is an environmental no-brainer. But charging infrastructure itself also adds to overall emissions. The greener the infrastructure, therefore, the quicker the payback.

 

So far, this has received little attention. As we ramp up charge points from thousands to millions, we must look at minimising their environmental impact, otherwise we may face backlash against a supposedly green industry.

 

The environmental impact of EV charger materials and manufacture

 

To deliver the environmental promise of EVs, we need a significant deployment of charging points. Zap-Map suggests there are currently over 18,000 public charge points in the UK, including 3,100 rapid chargers (as of April 2020). Millions could be eventually needed.

 

There is no official data on the environmental impact of these chargers (which itself should raise alarm bells), but we can make some educated, high level assumptions.

 

A standard rapid charger from a leading manufacturer is stated to weigh 195kg and made from stainless steel and composite plastics. For illustrative purposes let’s assume one third plastic (65kg) and two thirds stainless steel (130kg).

 

About 5kg of CO₂ is produced to manufacture each kilogram of plastic, and 6.15kg of CO₂ per kilogram of stainless steel¹. So, each charger would produce over 1.12 tonnes of CO₂ ². For comparison, a modern petrol or diesel hatchback produces 1.5 tonnes of CO₂ per year.

 

Some weight will of course be from the electronics and other miscellaneous materials. For simplicity we have included these within our plastic/steel calculation, though we assume their emissions per kg will likely be similar or higher. The limited data means these figures are not definitive , but they give an idea of the potential impact and the scope for improvement.

 

If all 3,100 rapid chargers listed on Zap-Map were manufactured from comparable materials, we’re talking nearly 3,500 tonnes of CO₂ already. The 14,500-odd slow chargers are smaller, but generally made of similar materials. If the numbers deployed of either, or both, grow exponentially – as is planned – that’s a big toll on our planet over the coming two decades, unless we see changes in materials and design.

 

Short lifespan, high waste

 

Waste is also a big challenge for chargers.

 

Many manufacturers claim chargers will last a decade, though it’s a poorly kept secret that many have lifespan of 5-7 years. Members of the Connected Kerb team have seen first-hand the graveyards of defunct charging kit across the UK. This is not only wasteful and damaging to the environment, but it also makes bad economic sense…infrastructure is supposed to last.

 

Making charging infrastructure out of recycled materials

If deploying these chargers was our only option, it would still be worth doing to enable EV uptake. But we can do better. Remember, the less CO₂ produced by charging infrastructure, the quicker the payback.

 

A central tenet of Connected Kerb’s mission is to make charging infrastructure greener.

 

Our charging points are manufactured from recycled tyres and plastic, so instead of mining new materials, we are reducing hard-to-recycle waste from the automotive industry. Our Armadillo is made from three recycled tyres, our Limpet from one. We are working on making our node box (which houses componentry underground) and ducting from recycled plastics, and we seek to use recycled aggregates to install our infrastructure in the ground.

 

The carbon cost of producing most of the materials that go into our chargers is close to zero, since they have already been made.

 

What’s more, we design charging infrastructure to last. The expensive and sensitive charging elements are kept secure, separate from the socket, in a below ground node box, where they are accessible for maintenance but protected from the elements and vandals (much like broadband infrastructure).

 

The below ground infrastructure acts as a foundation, supporting our charging sockets and wireless charging mats. This separation, or modularisation, minimises the physical and visual disruption on streets and also means that, in the event that things do go wrong, individual parts can be easily and quickly replaced, without the need to replace the whole system.

 

These features, scaled up across millions of chargers, add up to significant economic and environmental benefits.

 

Using charging infrastructure to encourage green behaviours

 

This article focuses on the materials and lifespan of today’s chargers, but it is worth briefly noting the comparative impact of rapid verses slow/fast charging on the environment. This is important, since the infrastructure we build today will influence the charging behaviours of tomorrow’s drivers and the associated environmental impact.

 

Firstly, slow/fast chargers require cars to be plugged in for long periods (eg overnight or at work), enabling smart charging that can help minimise strain on the power grid and batteries. This has the benefit of preserving battery lives and therefore battery waste.

 

Secondly, a vast network of vehicles plugged-in to smart chargers for long periods creates a huge amount of flexibility for the grid, enabling intelligent matching of supply and demand. This can facilitate effective use of renewable power (and switch off backup gas generation) where vehicles being charged smartly are able to take power when it’s abundant and cheap.

 

Thirdly, residential on-street and workplace charging opens EV ownership to people without driveways, thereby widening access and speeding the switch from ICEs to EVs. By contrast, as demonstrated in our published analysis of 1500 drivers earlier in 2020, public rapid chargers mostly provide extra options for existing drivers on long journeys, rather than for their habitual, day to day charging needs.

 

Charging should be green too

 

As part of our push to enable EV uptake, we should also make our charging infrastructure as green as possible.

 

This means demanding that chargers are made from recycled and recyclable materials. It means designing chargers to minimise materials and electronics. It means deploying infrastructure to last for decades. It also means designing infrastructure that fosters green charging behaviours.

 

We must not overlook the environmental impact of the infrastructure needed to enable EV uptake. In our understandable rush to enable EVs, the environmental credentials of the chargers themselves have escaped scrutiny, meaning manufacturers have not had much incentive to change. EVs are a green industry which will help to save the planet. Charging infrastructure should share this aspiration.

 

 

 

 

¹ These figures are approximations based on limited publicly available data. Our source for CO₂ emissions of materials was https://www.winnipeg.ca/finance/findata/matmgt/documents/2012/682-2012/682-2012_Appendix_H-WSTP_South_End_Plant_Process_Selection_Report/Appendix%207.pdf. Exact plastic compositions used are not published by manufactures but we have taken 5kg as an approximate figure for polyurethane, which we understand to be used. We contacted several charging companies about their environmental credentials and did not receive a response. We encourage transparency and will happily update this article with more definitive figures if and when the industry feels willing to share.

 

² Plastic (65 x 5 = 325kg) + Steel (130 x 6.15 = 799.5) = 1,124.5kg/1.1245 tonnes