Originally published on CleanTechnica
With several affordable vehicles on the horizon that will be capable of 200 miles or more of all-electric range, the last major problem for EVs and EV manufacturers to truly solve is super fast public charging, or what we have dubbed Level 4 charging.
Image courtesy Redditor Dakujem
Tesla is currently the only automaker to offer reasonable long-distance charging with its Superchargers running at ~135 kW, but that infrastructure is about to be pounded into the ground by hundreds of thousands of Tesla Model 3 owners unless something changes.
In the Model 3 unveiling last week, Elon Musk shared that Supercharging would be included with the Model 3 but stopped short of claiming that it would include free Supercharging, as has been the case with the Model S and X. This is a divergence from previous statements that Supercharging would be free for the Model 3.
Tragedy of the Commons
Looking at Supercharging, one of the key challenges is that it’s free. When humans can get something for free, even when it’s just a few bucks worth of power, we act irrationally and selfishly, which is a behavior captured in a theory call the “tragedy of the commons.” Per Wikipedia, the tragedy of the commons is:
“an economic theory of a situation within a shared-resource system where individual users acting independently and rationally according to their own self-interest behave contrary to the common good of all users by depleting that resource.”
Stories of wealthy Tesla drivers using Superchargers every day as their main charging solutions are on the forums and are evidence of this behavior. Spending 30 minutes every day to sit around to save $3 in electricity at home is not a logical behavior for someone driving a $100,000 car, and results in charging stations being unavailable for long-distance drivers.
Tesla has already reached out to frequent … excessive … abusive … and even some infrequent Supercharging users, asking them to take it easy … and this is just with the Model S putting load on the Supercharging network. Imagine when we have 2 more years of full production volume of the S and the X weighing down on it… Tesla Superchargers could be in for a world of hurt in no time, as defined by long lines and general unreliability of the Supercharging network.
Supercharging in Redondo Beach | Image Credit: Kyle Field
Fixing Supercharging doesn’t mean that all of a sudden everyone has to pay for Supercharging. Stepping back from the problem to look at why Supercharging exists in the first place helps us to understand what levers can be pulled to improve the system.
Tesla developed and deployed Supercharging to fill a functionality gap for EVs and to enable long-distance travel. That’s the base use case and in these early days of Level 4 infrastructure deployment, the key reason for Level 4 chargers. This is not saying that Superchargers are not great for a quick topup or for filling up after a long day of driving around town … but that’s not what Tesla built them for.
As Supercharging networks continue to grow, there will be a natural evolution of the system to support additional use cases, but in the meantime, there is an opportunity to leverage system controls to optimize system availability. Long-distance travel and fast charging become much more relevant considerations as EVs with more than 200 miles range become the norm — as long-distance travel with sub-100 mile range EVs is painful in most scenarios anyway.
The Radius Model
Finding the sweet spot in keeping the system functional while also assuring availability is a delicate balance but is not unsolvable. Implementing a system wherein charging closer to home is not free provides an incentive for EV owners to charge at home and lightens the load on the distributed public charging network that otherwise becomes clogged by the tragedy of the commons effect we typically see with free charging.
Great availability, low utilization | Image Credit: Kyle Field
For local charging within 50 miles of home, it is critical to bill for EV charging, as this is where 90%+ of all driving takes place. When local charging is not regulated, EV drivers gravitate towards utilizing public charging stations instead of home charging, which consumes charging spaces that could otherwise be useful for long-distance travelers. A healthy price point for local charging would be to use peak electricity rates.
For mid-range charging at ranges of 50–100 miles from home, an EV driver can still round-trip a destination on a single charge, so public charging at these distances is not absolutely required. Charging pass-through rates for power at mid-range charging stations strikes a balance that allows EV drivers to charge remotely without a penalty but clearly removes the incentive to “convenience charge.”
For long-range charging over 100 miles from the home, Level 4 charging can remain free as this is the intended use-case.
Implementing a radius model to govern charging ensures that chargers are available for the base use case while also giving EV drivers the freedom to utilize public super fast charging stations if needed, with minimal penalty. For EV drivers without home chargers, workplace chargers provide the best balance between cost, availability, and charging time.
As the Level 4 charging network catches up with EV sales growth, models can be adjusted to strike the right balance between cost, availability, and charging time. Currently, the balance is tenuous at best, but with Tesla being the only EV manufacturer to truly invest in a Level 4 charging network and ensure integration with its fleet of EVs, the balance is sure to deteriorate as Model 3 comes online.
Tesla Model 3 on the test track | Image Credit: Kyle Field
At the Model 3 unveiling last week, Tesla shared plans to double the Supercharging network by the end of 2017, and a parallel effort to improve the destination charging program with a planned four-fold increase in the same timing.
Building and managing Level 4 public charging is a key step to ensuring robust EV charging that meets the needs of EV drivers, but with Model 3 on the horizon, it is at a critical junction as EV adoption moves from the Early Adopters to the Early Majority and the volume of EVs on the road ramps up significantly. Left unmanaged, the volume of vehicles would quickly overwhelm the current and planned super fast charging network and render it effectively unusable.