Solar EV charging station feeds grid

Posted by Pete Danko, EarthTechling


A frequent criticism of electric vehicles (EVs) is that they're really powered by coal, since that's such a significant source of electricity.



Leaving aside the claim's validity (or lack thereof), you can't use it against cars taking advantage of the new six-vehicle charging station unveiled at the Electric Power Research Institute (EPRI) in Knoxville, Tenn.

A joint effort with the Tennessee Valley Authority (TVA), this grid-connected "Smart Modal Area Recharge Terminal" uses solar panels and batteries to make and store electricity for vehicle charging, and also has the capability of sending power back to the grid.



It's a prototype, with another such station being built at the Oak Ridge National Laboratory about 10 miles away.

After several months of testing, the plan is to have 125 charging spaces built in Knoxville, Chattanooga, Nashville and possibly other sites for use by researchers.

Now, it is important to note at this point these EV charging stations aren't powerful enough to do all of their charging off the solar power system, which have a generating capacity of 2 kilowatts (kW) and battery storage of 5 kilowatt hours (kWh). 



As a point of reference, the 2011 Nissan Leaf has a 24 kWh-capacity battery and can charge at up to 3.3 kW per hour.

But the Tennessee station's solar component does take a bite out of what the grid needs to provide - and, in a small way, helps boost grid stability.

EPRI and TVA will be watching closely to see how people use the system. 

"The data collected from these stations will help us to understand station performance, customer charging preferences and grid impact," said Mark McGranaghan, EPRI vice president of power delivery and utilization.

Pete Danko, EarthTechling