More Plugs, Less Power? The Surprising Math Behind Better EV Charging
Ultra-fast EV chargers make for great headlines, but they won't survive long if the companies installing them aren't making any money.
-
Installing high-powered EV chargers everywhere doesn't necessarily mean they'll actually be used by drivers.
-
That's what a new white paper from Kempower, a charging hardware and management software provider, found.
-
If charging networks want to make money and keep the lights on, they should focus on offering more choice, not more power, the paper said.
Megawatt charging is very cool, and a sub-10-minute top-up can add hundreds of miles of range to a compatible EV very quickly. But power isn't everything, according to a white paper published by Kempower, a Finnish company that builds EV chargers and provides charging management software to charging networks.
The paper, based on North American charging data extracted from the company's ChargEye analytics platform, argues that operators will make more money if they focus on installing more plugs at their stations, even if these stalls offer less power than competing locations. The number of plugs at a site correlates strongly with utilization, Kempower says—more so than the total installed power.
"Installed power barely moves the needle," the company said. "Charging site utilization climbs steadily as sites add charging points."
Revel-branded Kempower dispensers in San Francisco.
According to the data from Kempower, the more plugs a station has, the higher the utilization rate, which leads to higher revenue and a quicker return on investment. The company said that a station with eight plugs will deliver a utilization rate three times higher than a smaller station with higher-powered stalls.
One of the graphs included in the white paper shows the utilization rate going from roughly 3% for 100-kilowatt stations to a little over 5% for 400-kW stations. Meanwhile, going from a two-plug station to an eight-plug station will increase the utilization rate from roughly 2% to almost 10%. What's more, sites with eight plugs deliver more than double the energy (128,342 kilowatt-hours) compared to four-plug sites on average (61,453 kWh).
Electrify America large-format DC fast charging station in Santa Barbara, California
Per Kempower, the ideal power output for maximizing the utilization rate of a charging station when all the connectors are being used is roughly 100 kW. That's because most, if not all, EVs rarely take advantage of their peak charging power. So, even if a manufacturer advertises a peak rate of 300 kW, a 10-to-80% session might result in an average input of 100 kW to 150 kW.
Now, it's worth noting that Kempower specializes in building EV charging stations with distributed power and dynamic power management, similar to Tesla's approach with its Superchargers. The company, founded in Finland in 2017, argues that going for a distributed power approach makes it easier to scale a charging station later down the line, without having to invest heavily after the first stalls have been energized.
