If there's one thing that most people agree on when it comes to electric cars, it's that powering them with electricity generated by renewable energy is generally the greenest thing to do.

Solar is a popular choice with those in warmer climates, but even that endless nuclear furnace we call the sun isn't perfect--because it isn't always shining down on our solar panels.

GM's OnStar service and energy company TimberRock are looking at minimizing these disruptions with managed power and energy storage via the electric grid.

The basic premise is that solar power and even power from the grid itself is never constant.

There are peaks and troughs in demand and supply. If there's a peak when supply is low then energy can be wasted; if there's a trough when demand is high then there's a shortage of power.

Solar is particularly susceptible to this. Consider when your solar panels are absorbing the most solar energy--during the day. And when do you charge your electric car? Probably at night, while you sleep. The energy isn't being produced when it's needed.

TimberRock's solar charging canopies get around this by storing energy in a large battery system for whenever it's needed, and carefully metering out the energy needs of its small fleet of Chevrolet Volts. It uses an OnStar system called "Demand Response" to enable TimberRock to start, stop and modulate such a system.

Aggregation software can then apply this energy in the most efficient way. If there's an excess of it on a particularly sunny day and charging the Volt isn't a priority, power can be sent back to the grid to cover for any shortfalls.

The car could then be charged when grid demand is lower--still with clean, green solar energy.

While it would require owners to be happy with external sources being able to pick when their vehicle charges (a system of financial benefits is being suggested for owners willing to participate), it could prove popular with green-minded buyers.

“Down the line, this could really incentivize solar charging for EV drivers” said Paul Pebbles, GM global manager of Smart Grid and EV Services.

“This opens the door for solutions like this to be brought to the public, which could increase the benefits of owning an electric vehicle."

Would you be willing to participate in Demand Response charging to make running an electric car even greener? Leave your thoughts in the comments section below.


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