What Goes Into Determining EVSE TCO and ROI?

(Joseph Gottlieb, CTO, Tuesday July 13, 2021)

Two of the business concepts we see a lot with our customers when considering various EV charging solutions is Total Cost of Ownership
(TCO) and Return on Investment (ROI). While both are powerful tools for business decision-making, it can be challenging to utilize them correctly in the complex systems and situations that characterize infrastructure spending initiatives like fleet electrification. After all, EVSE is only part of a total solution that includes the vehicles and the revenue/services that they provide. Considering only one part of a complex solution often results in a TCO or ROI that is misleading.

A good example of this problem is performing a tradeoff between AC Level 2 chargers and DC fast chargers. Let’s assume each AC Level 2 charger (19kW of output power) has a price of $6K, versus a $60K cost for a 60kW DC fast charger. Let’s assume that the chargers  will be used to charge 100 refuse trucks, each with 300kWh of battery capacity, a range of 100 miles, and a charging window of 10 hours. The cost for 100 AC level 2 chargers would be $600K, but each AC charger can only supply 190kWh of energy in the 10-hour charging window, resulting in a range of 63 miles. If the routes for the current trucks are 90 miles each, you will need 42 additional electric trucks (and chargers) to cover all of the routes. If each truck costs $500K this increases the total solution cost by $21,252,000. If 60kW DC fast chargers are used, one charger can fully charge two trucks, reducing the number of chargers needed by 50%, and the total cost for DC fast chargers of $3M, with no reduction of range (i.e., no additional trucks required). The DC chargers would also only need 50 trenches vs 142 trenches, which would reduce the cost by $920K ($10K per trench x 92 additional AC chargers). The resulting deltas to the total solution cost would be:

  • AC Level 2 Chargers: 142 chargers ($6K each, $852K total); 142 trucks ($500K each, $71M total); 142 installation trenches ($10K each, $1.42M total) –> $73.27M
  • 60kW DC Fast Chargers: 50 chargers ($60K each, $3M total); 100 trucks ($500K each, $50M total); 50 installation trenches ($10K each, $500K total) –> $53.5M

As you can see, looking at the total solution cost yields a nearly $20M savings for the DC fast chargers vs the AC Level 2 chargers. Another way of looking at it is that spending the additional $2.15M for the DC fast chargers yields a savings of nearly $20M, for an ROI of almost 10X. And this doesn’t even include the crew and maintenance costs for the additional 42 trucks!

And if you are looking for made in the USA high-power DC fast charging systems for those EVs, look to Rhombus Energy Solutions. Our market-leading bi-directional EV charging systems (which are designed from the start for the needs of fleet operators) are designed and built in the USA. Rhombus also excels in the design of high-power smart inverters for next-generation renewable energy and energy storage deployments. Our expertise in energy management system (EMS) software is also embedded in our VectorStat EMS controller and software which is embedded in our EV charging systems and smart inverters. We have built over a thousand V2G-capable high-power, high-reliability chargers and bi-directional smart inverters for a variety of different sizes and classes of EVs. Find out how we can help you by contacting us at news@rhombusenergy.com, or by reading our Vehicle to Grid Solution Brief.