There are 3 major benefits to having a grid-tied solar electric production system, rather than being totally “off the grid”:
- You don’t have to purchase and maintain a set of batteries (save money!).
- You don’t have to find a place in your house to put all those batteries. (save space!)
- You get the joy of watching your electric meter run backwards (joy!).
“Net Metering” is an energy swapping deal with the electric utiltiy company. They take your extra electricity when you don’t need it, and they give it back to you when you do need it. When your solar PV system is producing more electricity than you are currently using, the extra energy goes onto the utility power grid. The electric utility company then sells it to your neighbors. Then when you are using more energy in your home than the solar PV system produces, the extra energy you need is pulled from the from the grid. The electricity you buy from the electric utility company at that point is free — until you run out of your solar production credits.
You’ll tend to produce extra during the daytime, and draw on your credit at night. Overall you’ll be accumulating credit during the summer, and drawing down your credit through the winter. In Seattle the days are so long during the summer that it produces enough during those few months to power a house through the rest of the year — even if the rest of those months are dark and rainy.
I have personally found the joy of seeing the electric meter run backwards so satisfying, that I have noticeably changed my electric use habits almost overnight. I am much more conscious of my energy use. I am much more likely to turn the lights off when I don’t really need them — when I can see by the light coming through the windows. Our system was designed to meet 90% of the expected annual electrical use of the house. I’m finding myself semi-consciously motivated to have this 90% system cover 100%. It’s a bit irrational, but even when I’m somewhere else I find myself turning lights off!
Experience the joy for yourself! Watch how it looks when the electric meter runs backward. Click below to see a 25-second video: