Many of the fleet managers we work with at Flipturn use cost per mile as a key performance metric. As you add EVs to your fleet, comparing the cost per mile of operating your EVs with that of your internal combustion engine (ICE) vehicles can help you understand whether you’re getting the expected ROI on your EV investment.

Since electric vehicles are powered by batteries instead of diesel or gasoline, vehicle efficiency is measured in miles per kilowatt-hour (kWh), rather than miles per gallon. So, to get the fuel cost per mile of an EV, we’ll want to calculate:

In this article, we’ll dive into three main factors that affect cost per kWh and kWh per mile, and how you can use Flipturn to identify the best opportunities to drive down each factor.

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Vehicle efficiency (kWh per mile)

Existing telematics systems often report the energy expended by EVs while driving. However, EVs also offer regenerative braking; when a driver lifts their foot off of the gas pedal, the EV automatically slows, feeding the excess energy back into the battery. 

Calculating kWh per mile for EVs requires factoring in regenerative braking and using the net energy total to avoid over-reporting cost per mile. Flipturn Connect uses both energy out and energy fed back into the EV in its reporting features. Our platform also provides visibility into regenerative braking performance across vehicles, helping fleet managers identify ways to improve efficiency, and therefore cost per mile, across an EV fleet.                    

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Utility tariffs (cost per kWh)

There are two factors that affect cost per kWh: utility fees for total energy use, and utility fees for maximum power demand. 

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Time of Use fees for total energy use

“Time of Use” fees are charged based on the total amount of energy delivered to your site, and vary depending on the time of day it is delivered. For example, the cost per kWh of charging between 4pm and 9pm, a common “peak” rate time, could be almost double the the cost per kWh of charging during common “off-peak” hours of 9pm to 10am. 

Flipturn Connect receives real-time data from charging stations on energy delivered within each charging session. We use this data to calculate costs from time of use fees with high accuracy, even if power use is often variable across the duration of the charging session, as shown below:

With this data, Flipturn connect lets fleets see if charging is taking place during peak times, and how much money could be saved by adjusting charging times. Fleet managers can then avoid peak Time of Use fees by charging vehicles during off-peak hours, which can be achieved via Flipturn’s charging management features.

Demand and facilities fees for maximum power demand

Diesel and gasoline are both priced by the gallon; if you buy 100 gallons of diesel, you’ll pay 100 times the price of a single gallon of diesel. With electricity, this often isn’t the case.

Utilities usually charge extra fees based on the absolute maximum amount of power your facility uses from the grid at any point in time over your entire monthly billing period. These fees are called demand or facilities charges on your utility bill. For example, if your site typically uses around 300 kW of electricity, but usage spikes to 600 kW at just a single point in time during that month, your utility will use that 600 kW amount, multiplied by the per-kW demand and facilities tariff, to calculate your bill. 

Beyond cost per mile reporting, Flipturn uses real-time data from charging sessions on power usage to calculate each site’s power demand curve. Fleet managers can use this data to identify charging events that caused power usage spikes, see a list of the worst demand peaks, and identify ways to drive down costs. Additionally, through Flipturn, fleet managers can also set charging restrictions to avoid incurring future demand fees, saving up to thousands per month per charger in utility costs.