A grid-tied solar system, also called "tied to grid", is a semi-independent electrical generation or grid energy storage system which links to the main grid from your home to feed excess energy back to the local main electrical grid. Or you can use it all yourself, paying zero dollars to your utility company.
If and when not enough electricity is generated (you used more than you produced with your solar system), electricity drawn from the main grid and your utility can make up the difference and that is what you pay at the end of the month.
Here is a simplified version of a grid-tie solar system attached to a residence.
In a nutshell, when you install a solar electric system, you are no longer just a user of electric energy from the grid provided by your utility. Now, you are also a producer of energy that, by law, has to be allowed to connect to the main electric grid as a user/producer. If your utility allows "net metering" (Austin Energy does), then any excess energy produced by your solar array and not used by you goes back to the grid. Austin Energy will pay you money for the energy produced and given back to the grid and that is called net metering.
The solar installation performed on your home has to follow all laws and regulations and has to pass an inspection by the city and by your utility. All connections to the main grid are to be performed by a licensed electrician.
Also, in many cases a new utility meter is required to be installed.
Just as in aillustration, here is a sample block diagram of a 3 kiloWatt residential solar array installation.
Click here to see what the sample of a small residential solar installation looks like. This is a block diagram of the installation.
Together with the technical diagram, all measurements and all calculations, this is submitted to the city and to the energy provider for approval.
So, instead of just spending and using energy - now YOU make it. It's a good feeling.