The Robotaxi Rollout #1: The Basics and How They Might Surprise You

With new autonomous driving vehicle services rolling out around the world, these robotaxis are seen as the pinnacle of autonomous mobility and serve as an inspiring example of where the future of transportation could be headed. And while the focus on this cutting-edge technology has been on the vehicles, the user experience, and the roller-coaster path to maturity, there’s a speedbump in the road that not everyone is seeing: how do fleets of driver-less vehicles charge themselves?

Crijn Bouman, CEO and Co-founder

Obviously a robotaxi has no driver. That’s the whole point. But in the case of charging, that presents a big challenge. Robotaxi fleet owners will typically build a charging hub staffed with human operators to keep vehicles charged and ready to roll. While that sounds simple, the reality is much more complex – and costly.

Most robotaxi services operate 24/7, and a single robotaxi typically charges 2-3 times per day in such operation. A typical charge will give them the ability to drive 150-250 miles, so in total a vehicle can theoretically cover between 300-750 miles in a day.

To build a competitive service, a significant number of vehicles is required. Cities like San Francisco have over 40,000 Uber/Lyft/taxi drivers, so to build a service of any meaningful scale, as many as 10,000 robotaxis could be required for each large metropolitan area. So, a whole fleet would need 20,000 – 30,000 charging sessions per day, requiring 40,000 – 60,000 plug in and plug outs between each robotaxi and charging station each day! That’s a lot of work to keep those vehicles in operation!

So how many people are needed to operate a 24/7 charging service at a charging hub and how many vehicles can they charge?

First let’s look at the minimum crew requirements. To operate 24/7 at any hub, regardless of the number of chargers installed, even for a single charger, we would need 8-16 people to run the show. Here’s why:

On weekdays:

3 shifts of 8 hour per day = 3 people
Back-up for gaps in schedule (lunch and bathroom break or absence) = 1 person
Total: 4 people @ 40hrs/week

On weekends:

3 shifts of 8 hour per day = 3 people
Back-up = 1 person
Total: 4 people @ 16hrs/week

So, we need 8 people per hub, even if we only have a small amount of chargers installed. And that is conservative, as we assume we can share the back-up person over all 3 shifts or have somebody doing something else filling in the gaps in the schedule, in each individual shift. Each hub will have to be equipped with things like breakrooms and restrooms to accommodate the on-site staff. Plus, due to safety and security, it might not always be possible to have a single person working alone, potentially doubling the number of on-site staff required per hub.

Now, if the minimum crew is 8 people, let’s have a look at how many vehicles a crew could serve.

Plugging in the vehicle and confirming charging has begun will take around 30 seconds, with unplugging takes slightly less time (press stop, unplug cable). And since staff won’t always be at a charger, we also must consider the amount of time a vehicle is sitting parked and waiting for someone to plug in the charger and the time it takes for the staff to notice when a vehicle is adequately charged, Which is typically communicated through some system in the robotaxi operator IT environment.

Assuming each hub will have around 30 parking bays and that it takes roughly 30 seconds for staff to become aware of the upcoming task walk over and plug in or unplug a vehicle, we then have:

Plugging in: 30 seconds + 30 seconds = 60 seconds
Plugging out: 20 seconds + 30 seconds = 50 seconds

If the whole charging cycle takes 110 seconds per vehicle, a single staff member operating at peak efficiency can support around 32 vehicles (3,600 sec./110 sec.) per hour at best.

The ride planning system can ensure that the charging stations operate at the maximum efficiency, but we are also dealing with uncontrollable factors: vehicles may be delayed in traffic, parking correctly consumes time, operators may be on breaks, or busy with another vehicle, or simply not paying attention. These factors cause inefficiency and reduce the ability of the staff, bringing us down to about 70% of the theoretical maximum capacity, or about 22 vehicles per hour and 528 vehicles in 24 hours. And if a single robotaxi needs to charge at minimum twice per day, this means that a single hub could support 264 vehicles.

If 10,000 robotaxis are required in a major metropolitan area, and a single hub can only support 264 vehicles, this means we would need 38 hubs to support those vehicles. If each hub has a have a minimum staff of 8 (which we said earlier was conservative), that’s 304 total staff required just for basic charging! And that’s just the on-site team. There’s also management, HR and administrative roles, facility support and the added costs of each hub – breakrooms, bathrooms, security, etc. All of this adds up to millions of dollars, and that’s just for a single city. An ambitious robotaxi company will look to expand to new locations, further increasing those costs into the tens of millions. Additionally, the job of being “bossed around” by a fleet management system to perform the task of plugging-in and out vehicles all day, may not be the dream career for many people, so hiring a crew of 300, and motivating and maintaining them is a major challenge in itself.

With all this in mind, it’s clear that manual charging in a scaled robotaxi operation makes no sense from a business perspective. So, if these vehicles can drive themselves, why can’t they charge themselves too? A robotic system can work 24 hours a day and handle the mundane task of charging all without the need for breaks, supervision, training, or the need for on-site facilities like breakrooms or bathrooms.

At Rocsys, we believe that the best charging experience is the one you don’t have. Through a combination of soft robotics, advanced AI, and cutting-edge computer vision technology, we have developed a robotic solution that integrates with any industry standard charger to make the entire charging process completely hands-free. This allows anyone with a fleet of electric vehicles to unlock greater efficiency in a cost-effective way. And for self-driving vehicles like robotaxis, hands-free charging closes the automation loop, creating a truly autonomous operation, and unlocking the full potential of their vehicles.

If autonomous electric vehicles are going to succeed, charging remains a major bottleneck that needs to be addressed. As we continue this series, we will look at the different strategies robotaxi companies can take to roll out this network of charging stations to minimize down time and efficiently meet the demands of a major metropolitan city.

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