Saturday, March 17, 2012

Is It a Jungle Gym or an Electric Charging Station?

Public electric vehicle charging stations are starting to pop around Houston and other cities in a noticeable fashion. According to eVgo, nine are currently operational around town (six of which are in parking lots of Walgreens stores).

Recently, while driving on Bissonnet toward Buffalo Speedway, for the first time, I saw someone actually charging their car. Most people wouldn’t have noticed the light blue Nissan Leaf pulling into the charging station at HEB, but given my interest in oil use and electric vehicles, this was exciting: I turned into the HEB parking lot and stopped to talk to the vehicle owner, who was there with his two preschool-age boys.

Suddenly, I heard a crash. The older of the two boys, who was about four, pulled the electric plug of the charging station out of its holder (the equivalent of a nozzle at a gasoline station) and fell down, taking the plug with him. The plug did not break, but it suggested to me that these stations might take more abuse than a traditional gasoline pump. Most parents would absolutely forbid their little kids from touching a gasoline nozzle considering the dangerous chemicals in gasoline. Yet the electric plug seems safer and much more attractive and inviting to play with than a gasoline nozzle.*

My other surprise came when I was back near my hometown of Bethesda, Maryland and saw an electric vehicle charging station with a large solar panel on top. This is great marketing to consumers who want to feel green, although it is extremely misleading. The solar panel cannot contribute much electricity. According to the website, the station produces an average of 7.5 kWh/day of electricity. As a comparison, the battery of a Nissan Leaf is 24 kWh, so the solar panel produces enough electricity to power one car every three days. Also, this electricity is extremely expensive, probably least three times as expensive as grid electricity and possibly more. According to, whose figures correspond with many other sites, the levelized costs of residential solar, which if anything is larger and cheaper than this panel, is 29 cents/kWh in sunny places and 63.8 cents/kWh in cloudy areas, and Maryland is not a particularly sunny state, getting something like half the annual solar radiation of Southern California or Arizona. In comparison, Maryland’s average residential price for electricity is around 13 cents/kWh. Then again, for consumers similar to those who are willing to pay about $1,800 for a Prius solar panel that powers a fan to keep the inside of a parked Prius cool, maybe that extra cost is a perfectly acceptable tradeoff.**

*At least it should be safe in California, which has the following regulations: The safety features required by the state of California for EV charging stations include a connection interlock that prevents electrocution by stopping the flow of electricity when it is not charging a vehicle. There are also ground-fault circuit interrupters to prevent against electrocution. An automatic deenergization device cuts of electricity if there is a strain on the system (such as exposed wires). Finally, there is a ventilation interlock system to prevent the buildup of harmful gases.

** On the Toyota Prius website, I was able to get some information on vehicle packages, at least for my ZIP code 77098. On the Prius III, the Navigation package is worth $1,930 vs. $3,730 for the solar package, and on the Prius IV, the Navigation package is $2,380 compared with $4,180 for the solar package. The only difference ($1,800) between the two are the solar panels.

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