How Sustainable Are Public Phone Charging Solutions?

In pursuit of sustainability, we’ve embarked on a profound journey to determine the environmental footprint of our business operations and the life cycle of our charging solutions. Collaborating with expert third parties, we’ve analysed and dissected the carbon emissions of our entire operation. The result? We have already taken significant strides toward achieving our goal of NetZero emissions by 2030.  Contact us for our latest report which shows over a 30% reduction compared with 2019 on a constant revenue basis.

For a long time, we’ve championed the belief that alternative solutions simply can’t match the sustainability performance of ChargeBox. It’s this unwavering conviction that propelled us to dig deeper into the sustainability (or otherwise) of rented power banks. 

While the term “sustainability” is scattered across the websites of providers offering such solutions, you’ll also notice a distinct lack of details with more in-depth reading. The mere presence of a “sustainability officer” doesn’t inherently drive meaningful change. So, we’ve decided to pull back the curtain and reveal our research and findings for a comprehensive understanding.

Remember first of all, that power banks have a limited lifecycle. Given the amount of valuable materials in them together with the effort to mine, refine and produce battery packs, we wanted to see what the lifecycle emissions of a power bank solution would be. 

We have included references to scientific literature and other sources of data for our calculations and to show full transparency but are happy to share our calculations or even amend them, if better data can be provided. 

What we found truly shocked us! Our data and calculations are shown below but first, let’s summarise what we have used as relative comparisons before looking at the results. 

Comparing ChargeBox Charging Stations With Power Bank Charging Stations

Our own charging stations with 6 lockers can charge well in excess of 100 devices a day – and frequently do. So, we have compared a large 40-power bank charging solution with our ChargeBox FAST6. Here’s what we included for this analysis as well as what we didn’t include:

• We have included the embedded carbon in the respective machines – a recent model ChargeBox FAST6 6-locker USB Fast charge station and a 40 power bank charging machine (which we have estimated). We have assumed a 5 year operating life for both solutions (most ChargeBox stations go on considerably longer).¹
• We have included the emissions from expected electricity consumption during that 5 year lifetime if operated in the UK using our typical emissions per unit of electricity. Here we have assumed similar electricity usage, though power banks introduce an extra level of loss that we have assumed conservatively at 10%.²
• We have not included emissions involved in installation and service activities for both solutions, though these are expected to be similar.
• For the power bank solution, we added in the embedded carbon to produce each Lithium-Ion battery based on a scientific paper with such metrics. We did not include embedded carbon in casing and cables, or for transportation from Asia.³
• We estimated the number of power banks that would be required over the 5 year lifecycle based on expected failure rates as well as losses due to other factors such as customers keeping the devices.⁴
• We did NOT factor in end-of-life recycling and re-use.⁵
• We ran our numbers both with an equivalent number of charges provided over 5 years, as well as using a much lower number for the power bank rental solutions which is our expectation of real usage.⁶

Power Banks Produce 26 Times More Carbon Emissions Than ChargeBox

If a power bank rental solution provides the same number of charges as a ChargeBox over a 5 year cycle, then we calculated the emissions of that solution to be over 33 tonnes of CO2 compared with just 1.2 tonnes for ChargeBox.  This is both in total and per charge (since the charges given are equal). 

In the case that the power bank solution provides just 1/5 the number of charges of a ChargeBox (which of course means just 1/5 the number of satisfied users), then the power bank CO2 emissions drops to around 8 tonnes – still 6 times more than ChargeBox with just 20% of the service given. 

Usage Scenario	Same Usage	Power Bank 1/5 of ChargeBox Usage
ChargeBox emissions (tonnes of CO2)	1.2	1.2
Power Bank rental emissions (tonnes of CO2)	33	8
Comparison	ChargeBox emits 26 times less carbon	ChargeBox emits 6 times less carbon but charges 5 times more devices
Carbon per charge	Power Banks 26 times more	Power Banks 31 times more

We also varied our assumptions to see if battery loss/failure rates were much lower than what we believe to be the case. Even here, power banks solutions emit 12 times the emissions per charge given in the scenario of a 1/5th usage (over 3 tonnes total) ; and 7 times for equivalent usage (over 9 tonnes).

We will happily re-work our model if credible alternatives are presented to us for any of our assumptions. Climate calculations are very difficult to do accurately and we would always caution about differences of as much as 50%. But when the differences represent at least an order of magnitude, there is little doubt that such solutions are not comparable on a sustainability basis.

Is 33 tonnes of CO2 emissions a lot? 

It’s equivalent to:

• 39 seats on a flight from London to New York
• 6 years of a single person’s carbon emissions across all their activities (average UK person)

Remember also (if you read the footnotes) we have not factored in extra embedded carbon from machine manufacture in China, and freight emissions for both machines and batteries. Both of these would result in additional emissions for power bank solutions but do not apply to UK-manufactured ChargeBox. 

Of course, you might argue that both solutions are worse than charging at home.  In the case of the power banks, it almost certainly is, but with ChargeBox it would be similar to charging at home.  While we are at the mercy of our hosts in terms of how they procure their energy, we encourage all to use 100% renewable – as we do in our own operations. 

If you’d like to know more about a sustainable way to keep your visitors, guests, students and patients’ devices charged, drop us a line – we’d love to hear from you.

Thanks for reading!

 Chargebox

¹ We have used our own embedded carbon as a reasonable estimate of embedded carbon in the power bank charging machine. The reasoning is that it is a similar size metal box, with similar types of electronics, screens and other components. We have NOT allowed for the fact this is produced – most likely – in China which has carbon emissions relating to electricity in production at more than 2x the UK where ChargeBox is manufactured (and even here, our metal fabricator uses extensive solar energy installed on its buildings which was not factored into our calculations). We have also NOT allowed for emissions due to shipment of the units from China to the UK.

² We have calculated both the base level electricity to keep each machine functioning and the electricity used to charge either the power banks (power bank solution) or devices directly (ChargeBox) during a 5 year lifetime in the UK and then used the UK’s electricity emissions number (which was 181g.CO2/KWh in 2020 and is probably a bit lower now). The electricity for both will be similar per use, though the power banks introduce an additional efficiency loss and we included a figure of 10% in our calculations. The amount of electricity consumed by either solution was not hugely material or different. With the scenario for 20% usage of power banks compared with ChargeBox that would translate into lower electricity emissions – but obviously producing less charged devices.

³ We added in the embedded carbon we calculated is in every power bank based on a scientific paper outlining such a figure for any type of Li-ion battery. This did not include extras such as cases or cables. The paper estimated the embedded energy required to make a battery, and we then used the figure for China’s electricity emissions per kWh as stated here

⁴ We varied our assumptions on these figures to see the impact, but in every scenario, there was still a significant impact. Our base level estimates were taken from the experience of one of our international partners who also operates a power bank rental solution

⁵ With ChargeBox we responsibly recycle all metalwork and after re-test, we will re-use some electronic components and wiring. Power bank rental companies may or may not recycle their failed batteries, but for those that are lost or kept by customers, there is likely a significant carbon cost. It is our expectation many of these end up in drawers and eventually landfill. 

⁶ Most ChargeBox usage is free so is at very high levels; most power bank usage is charged for, so usage is lower. We ran numbers for both equal levels of high use, and 20% use for power bank solutions – so just 1/5th the number of devices charged. We used 50 uses/day for ChargeBox – a typical value. We then compared 50 uses/day for the power bank rental as well as the scenario of just 10 uses/day. We have used values from both scenarios and also shown an equivalent number of emissions per charge.