Charger Deployment Study



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Sunday February 26, 2017 Charger Deployment Study I just came across a study done at the University of Ohio by Xiaomin Xia, Ramteen Sioshansia, and Vincenzo Maranob that attempted to model and optimize the deployment of charging infrastructure and while it wasn't perfect they did come to conclusions similar to what I have been preaching for a while now.


The study developed a model to simulate and optimize the placement of charger infrastructure to determine where to place EV chargers to maximize their use by none fleet owners of electric vehicles. 
Like any such study the results will often depend on the assumptions going into the model and in this case their assumption was to base the model on an EV with 73 miles of range which corresponds to the Nissan Leaf.  Since this study was done around Columbus, OH this is a pretty good selection since the most available EVs there are the Nissan Leaf and Chevy Volt.  However, the situation is changing as manufacturers are now beginning to release their second generation of EVs which typically have a range of around 120 miles, while the Chevy Volt and the Tesla models all have a range of over 200 miles.  Having said that, there is a large number of low priced low mileage used EVs on the market at the moment which fit into the studies assumptions nicely.


One of the places where I thought that the study was lacking is that they only considered level 1 and level 2 charging but made the assumption that DC fast charging was not relevant to charging being installed in residential areas.  I think this was an oversight for of the study as I believe that fast charging is going to have an increasingly important role as the rate of EV adoption continues to climb. 


The study also looked at the impact at a variety of funding levels from $0.5 million to  $3.5 million to provide public charging for an area of about 2,320 square miles that is home to 1.7 million people who collectively own 1.1 million vehicles.  They looked at installation of charging locations in three different types of location, workplace charging, University campuses, and shopping centers.  The area was divided into 17 travel regions but assumptions for average miles travelled for each of these regions were not specified in the paper. 


Other thing I took issue with was the cost they assigned to the install the chargers, and the 1% desired EV penetration rate they used in the study.  The study assumed that it would cost $425 to install a level 1 charger and $925 to install a level 2 charger with the assumption that any required equipment like transformers were already available.  From what I have seen this is grossly underestimating these costs particularly for the level 2 charge which can be as much as $6,000 per unit to install.  The cost for level 1 is closer assuming that places can just utilize already existing 110V outlets but running additional outlets is still likely to be more expensive the $425.  The target of 1% penetration is probably OK for Columbus, OH but here on the west side of Los Angeles we are already above that level. 

I still think that many of the results they got are quite valid though.  In their modeling they found that it was most cost effective to install level 1 charging at workplaces when funds were at the lower level of the scale.  This is something I have been saying for a long time.  At my office I don't need a $2 an hour level 2 charger that is going to top my car up in less than 2 hours and then leave me hogging the charger for the rest of the day.  Of course I would move my car after the charge was complete but most people don't.  Access to a 110V plug at their parking space is all that most EV drivers need.  In fact Level 1 charging is good for any location where people stay for a long time such as long term parking at airports of railway stations. 


The study also found something else that we already knew, about 96% of drivers would be able to meet their daily driving needs by charging at home.  This is one of the interesting things about the EV market.  One of the things that discourage people from driving electric is the lack of EV infrastructure yet once they buy an EV they find that for the most part, they just need to charge at home, and need to use public chargers very rarely.  Of course there is still a significant proportion of people who live in places like apartments where they don't have the ability to charge at home and public charging infrastructure is key to EV adoption for this segment of the population.


In the Study, as funding levels increased the indication was that adding level 2 charging at places where people stay for shorter periods of time became more beneficial.  In the model this allowed enough charging capacity to meet the charging needs of most of the remaining drivers who drive into the area where chargers are installed.  At the $3.5 million funding level only 1% of drivers cannot make their daily travel needs.


Anyone who has been following my blog will know that this study confirms what I have been saying for years.  However, even though it was published recently it is already out of date.  I would like to see this study being redone but using a criteria that better matches what the driver of 2018 is going to see.  That includes a mixture of plug-in vehicles that includes a mix of vehicles with ranges like the ones we have in this study, cars that have an average range of 120 miles, and cars that have a range of 200 miles.  The study also needs to take into account the availability of DC fast charging.  target penetration should be reviewed at both 2% and 5% levels.


Now just let me get on my soap box a little.  One of the biggest issues with charging infrastructure is that while the chargers are there it doesn't mean they are available.  One of the issues often brought up when it comes to funding public charging is that chargers often sit unused.  In this area where EV adoption is some of the highest in the nation I often see chargers being blocked mostly by EVs using the charger as a convenient parking space.  At other times the charger is blocked by someone who parks there for a long time after charging is complete.  It is rare to see chargers being blocked by ICE cars anymore but it still happens once in a while.  Along with charging infrastructure being installed there is a strong need to establish rules for using the chargers and to enforce there rules.


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