One of the key challenges for organisations when electrifying their fleets is to install an adequate charging network to support their new vehicles. This charging happens at depot sites, where vehicles park out-of-use, mostly overnight. This approach, however, only works well if the depot has a power supply capacity that matches the needs of an electric fleet. Whilst it is usually possible to install a few charge points to support a couple of electric vehicles, most depots need a large power supply upgrade before meeting the demands of a large electric fleet. This is very costly, and there has not seemed to be a good alternative, until now.
Over the last year, we have been working with our partners at Imperial College London to identify ways of limiting the need for depot-based charging for fleets, thus reducing the requirement for large depot upgrades. Apart from load balancing and smart allocation of vehicles - which we have talked about previously - we wanted to explore whether vehicles could be charged off-depot on a consistent basis.
In our case study, we have worked with the Royal Borough of Greenwich’s 550 vehicle fleet, which are used to service council housing, maintain parks, collect waste and oversee improvement works.
We analysed a year’s worth of telematics data from the fleet, with detailed information about the stop and start times and locations of vehicles. The data has allowed us to identify the duration and location of stops the vehicles made in order to see whether any patterns emerged. We hypothesised that if we are able to find locations where vehicles stop regularly for long periods, we would be able to install EV charge points that can be used to top-up the batteries of these vehicles. If these stops were long and frequent enough, the vehicles might never require charging at a depot, thus reducing pressures on the depot’s electricity supply.
From our survey work with the drivers, we understood that as a minimum, stops of over 30 minutes should be considered, making it worthwhile for a driver to spend time plugging in a charger. Commonly available chargers of 22kWh are able to provide ~10kWh in half an hour, which is about 25% of a full charge on commonly used electric vehicles today, like the Nissan eNV200. That level of extra charge is sufficient for about 40miles (65kms), which is slightly over the average range of what many council vehicles drive in a day in Greenwich.
Considering these details, we have plotted all stops of over 30 minutes on a map, aggregating stop locations to small hexagons. The heatmap below shows the number of stops within a year that have been made within those hexagons.
For those familiar with Greenwich, you can see the borough’s boundary appearing. The additional stops in the surrounding areas are linked to take-home vehicles (where a driver would take a vehicle home) or trips associated with other activities.
We have further narrowed down the analysis to look at areas where vehicles stopped at least 500 times over the year, meaning approximately two stops per working day. There were 62 such locations in Greenwich, all of which could be potential sites for off-site charging points. When analysing these sites in detail, they were linked to social housing blocks, park and cemetery entrances, hardware stores and council offices. As one might expect, this presents a clear opportunity to look at using charging points in those locations to support the fleet’s requirements. Outside of council’s working hours, or through smart booking systems, these chargers could also be used by the residents to charge their own vehicles, maximising their utilisation and hence usefulness to the community.
We are continuing to work on refining the methodology of this approach to make it relevant to any local authority fleet in the country. We strongly believe that providing a wider network of chargers that fleets can use will make electrification a more reliable and resilient option for fleets, massively reducing depot upgrade costs and also providing a valuable charging asset for residents.
And, if you have been wondering what was the most visited spot in Greenwich by the council’s fleet over the last year, it was a small car park near housing estates and a food store in the heart of the borough. The people keeping The Royal Borough of Greenwich working need to have lunch, after all. Unsurprisingly, there is already an EV charging point there…
If you’re interested in finding out more, you can reach DG Cities’ Head of Delivery, Balazs Csuvar, at balazs.csuvar@dgcities.com.
