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Grid Tie Systems

Just what is a grid-tied PV system?
It is a photovoltaic (PV) system that interacts with the utility. It can be designed with or without batteries and utilizes a relatively new breed of inverters that can actually send any excess power produced by your solar array, back to the utility grid, spinning your power meter backwards and selling your excess power to the utility.
 
If you are concerned at all about utility rates going up and would like to do something to reduce your monthly electric bill, then a grid-tie solar system may be just the thing for you.  The solar modules can be mounted on your roof or out in the yard where they sit quietly generating power from the sun that you can either use directly or sell back to the utility company.

If your utility company will allow you to connect your PV system to their grid, the next question to ask is if they will buy the energy back at the retail or wholesale rate. Ideally you want the utility company to buy back any excess electricity that you produce at the same retail rate that you buy electricity from them at. This is called "net metering" and is the simplest way to setup a grid-tie PV system. In such a system you only typical grid tie diagramhave one utility Kw meter and it is allowed to spin in either direction depending on if you are buying or selling energy. Ideally you want the utility company to buy any excess electricity that you produce, at the same retail rate per Kw that you by electricity from them.

The off-grid system pictured here is a typical grid tie system using one inverter to control the solar array. The disadvantage of this type of system is that you must size the inverter to the solar array or vise versa.

Remember, a "net metering" law for your state doesn’t necessarily apply to rural electric cooperatives so give your utility company a call before going any further.

What it Takes to Install a Grid-tie PV System
Check With the Utility Company
The first thing you should do is contact your utility company to see if they will allow you to connect a solar system to their electrical grid.  While there is a national law that requires investor owned utility companies to allow interconnection of a solar or wind power system, rural electric cooperatives are exempt from this law.
 
Buy Back Rate?
If your utility company will allow you to connect your PV system to their grid, the next question to ask is if they will buy the energy back at the retail or wholesale rate.  Ideally you want the utility company to buy back any excess electricity that you produce at the same retail rate that you buy electricity from them.
 
Net Metering or Not?
This arrangement is called "net metering" and is the simplest way to setup a grid-tie PV system.  In such a system you only have one utility kWh meter (kilowatt-hours) and it is allowed to spin in either direction depending on if you are buying or selling energy.  In a non-net-metered system, the utility company will require that you install a second kWh meter.  It records any excess energy that you sell back to them.  They will only pay you the wholesale rate which is usually only a few cents per kWh.
 
Check Your State Regulations On-Line
To find out if your state offers "net metering" or any other incentives for installing a renewable energy system, click on the following link (www.dsireusa.org).  Remember, a "net metering" law for your state doesn’t necessarily apply to rural electric cooperatives so give your utility company a call before going any further.

Grid Tie Without Battery Backup

grid tie without battery

Grid Tie With Battery Backup

grid tie with battery back up