ECOtality charging points

ECOtality charging points

Studying the latest presentation from the EV Roadmap 6 conference held recently in Portland, Oregon 30–31 July, we find all sorts of interesting and important facts on how plug-in vehicle drivers are using the public charging infrastructure within the US.

ECOtality - the company that leads the DOE funded EV Project - to date installed couple thousand commercial AC Level 2 charging terminals and approximately 80-90 DC fast chargers (CHAdeMO).

Here is the map published in June (note that other documents suggest there are no over 3,000 AC charging points installed in US under the EV Project):


The most important slide is on utilization of non-residential infrastructure (commercial AC and DC), which shows us something rather interesting:

Utilization of non-residential infrastructure in EV Project

Utilization of non-residential infrastructure in EV Project

We see that there are 10,000 DC fast charging sessions per month, which works out to an average of 111 sessions a month per unit (so there must be 90 or so DC units here installed), or almost 4 sessions a day!

In Portland, Oregon - where conference was held - we see a slightly smaller number of sessions per unit (this indicates that approximately 16 chargers are in the area).

The highest utilization of DC chargers is in San Francisco where 20 units are used around 200 times a month on average.

On the flip side, we have Level 2.

ECOtality says there are 30,000 charge events for AC L2 commercial charging points per month. This is three times more than DC, but the number of sessions a month per terminal is just 7, about 16 times lower than the quick-charge DC average! The result for Portland is even worst at 18 times lower.

Additionally, 30,000 divided by 7  shows us that over 4,000 Level 2 chargers have been installed under the EV Project.

Now, when we know these numbers, we can go straight ahead and say that DC is used 4 times a day on average . In comparison, the AC points are used on average 7 times a month and 0.23 a day (once per 4-5 days). This is precipice.

This data confirms that slow public AC charging isn't very popular. And the reason is the charging time. If EV drivers need to recharge in public to finish a journey, they typically need it done quickly. Of course, AC slow chargers are a welcome addition, but the numbers don't lie.

Of interest too are these other slides on usage time of day and session length, from which we see that about 25% of DC charge sessions are 10 minutes or less and 44% are 15 minutes or less:

Session length

Session length


Source: The EV Project