Challenging our assumptions about commercial EV’s: Will they make the grade?

Why this information matters

One of the most talked about barriers in switching from ICE vehicles to EV vans and trucks is range anxiety. People are looking for evidence that an EV can do the job as well as or better than an ICE vehicle. They are legitimately concerned about the loss of time and productivity while a vehicle recharges, or the risk that vehicles will limp back to base with little battery charge left.
SwitchMyFleet has been engineered so that EVs return to base with comfortable levels of spare battery – no matter where they go. Problem solved … but wait. Is it?

What goes up must come down

Stating the obvious, New Zealand is a hilly country. If most commercial EVs are used within cities, or travelling from cities to satellite towns and back, fleet operators will be wondering what the impact terrain has on battery usage, which might make them question the suitability of EVs for the job. There are 3 factors that must be considered:

Figure 1 - Balancing the 3 journey components

We’ve done some research into this, applying the physics of moving vehicles, geospatial data, and route optimisation algorithms, and the results might very well surprise you – and give you the confidence to transition to EVs sooner rather than later.

We analysed two types of vehicles to test our hypothesis: 1. a light truck (4 ton vehicle mass; 3 ton payload) and 2. a medium truck (8 ton vehicle mass and 6 ton payload). This story is about the results of the light truck (a suitable choice for our scenario).

There will be a future story about the medium truck (hint: the results are similar).

A comparison of how EVs perform on a flat, fast road versus a winding, hilly road

We tested a scenario where a Christchurch-based business delivers goods to Akaroa (our winding, hilly road) and Ashburton (our flat, fast road) – about 160kms for both return journeys.

Figures 2 & 3 - Long sections of the two routes

The criteria

For deliveries to satellite towns from major centres, we thought that fleet owners or owner-drivers might consider a 4-ton light truck with a 3-ton payload and for the battery size, we chose 150 kWh.

Our vehicles will follow optimised routes that consider time, distance, average road speeds, and road types.

Our hypotheses

Christchurch to Ashburton return

Our hypothesis here was that the EV would not require a recharge en route because the route is relatively flat, and the road speed is relatively constant. We assumed that the energy used would be considerably less than the Christchurch to Akaroa journey because the route along SH1 is a flatter (albeit faster) road.

Figure 4 – Christchurch – Ashburton route (81 km one way)

Christchurch to Akaroa return

We hypothesised that the number of hills and the steep gradient of those hills on State Highway 75 between Christchurch and Akaroa would mean that the driver would need to recharge the EV in Akaroa in order to make it back to base in Christchurch. Due to the number of steep hills and the small distances between them, the EV would not have sufficient “bandwidth” to regenerate much energy through braking.

Figure 5 – Christchurch – Akaroa route (81 km one way)

Our findings

The EV model forecasts that the energy demand is the same for both journeys. This is despite the EV having to climb to 470m – twice – on the Akaroa journey.

The graphs below illustrate the cumulative energy consumption for each return journey of the same distance - one with a significant hill. You can see that in the Christchurch to Akaroa return journey, the EV recovers enough energy going downhill to effectively “flatten” any impact of the hill.

Figure 6 – Christchurch – Akaroa journey energy consumption through the route

Figure 7 – Christchurch – Ashburton journey energy consumption through the route