Wednesday, February 20, 2013

Green Backup Power

After Hurricane Sandy, having a backup source of power for your home has become more important to some people.  Using a gas generator is one option, and they are very economical to buy, but not necessarily to run.  After Sandy, it was tough to find gasoline.  Another option is to have a permanently installed natural gas generator, but this isn't a good option in an all-electric home.

If a lengthy power outage ever hits Denver, those of us with large PV systems will be kicking ourselves for not installing an easy way to go off grid.  You see, all the PV systems you see on private houses currently DO NOT WORK if the grid is down.  The average refrigerator has $200-$300 worth of food in it.   I'm allergic to most candles, and they are a great way to burn your house down, so backup electricity would be nice.

I'm sure that the big power purchase agreement providers, SunRun and Solar City, are working on this, and I'll post the answer here when I get it.

EDIT 3/18/13:  The inverter company, SMA, will be releasing a new inverter that has this functionality.  It will have "an emergency power supply to provide daytime power in case of a grid outage".
This is expected in 2013, so be sure to request it for your house.
The ultimate system will use your electric vehicle or plug in hybrid for electrical storage and backup power.
R. Carter Scott plans to do this, and I'm sure he'll report more about it.


  1. Kevin:

    I've come up with a fairly cheap solution.*

    I had my electrician install a straight blade receptacle and an interlock switch on my sub panel. I can connect my Prius to a pure sine wave inverter and I connect the inverter to the receptacle and I can run most of the items in my house (no 220 items or microwave).

    Based on my calculations, with a full tank of gas, I can have power for just over 4 days.

    Ironically, the power in my town is very reliable, but it's nice to know that I have a good plan "B".

    * It's only cheap if you already have a Prius!

    Mark Freeman

    P.S. You can come check it out next time you are in the area.

  2. Thanks for the update, Mark. Sounds like a simple solution.
    Would you also be able recharge a plug-in Prius with solar? Finding gas can be a problem during a crisis.