Demystifying the terms “Grid-Tied” and “Battery Backup” by tania

Our name is One Block Off the Grid but we don’t work block by block and we don’t take homes off the grid.  It’s a more of a metaphor, so let me at least explain why we don’t take homes off the grid, what it means to have a grid-tied solar installation, and what are the benefits.

A grid-tied system is an electricity-generating system that is linked to the normal utility system of a household.  In other words, it’s simply an extension of your existing utility supply.  Being hooked into the grid allows for net metering which means:

If your solar panels are producing more electrical power than you’re using:

1. That solar-generated energy will be sent back into the  grid and can be used by neighbors others on the grid.

2. The utility company gives you credits for that extra energy: your electric meter will spin backwards, and your monthly electricity bill will be lowered. (We’ll talk about this a bit more when we cover net metering below.)

On the flip side, if you need more electricity than is being generated by your solar system (say at nightime):

1. Electricity will be drawn from the utility grid for you to use, just as it is traditionally done.

2. Your electricity meter runs forward.

Because of net metering, grid-tied system owners receive the full value of the electricity produced by their system.  It measures the net difference between the electricity you take from the utility grid and the electricity you feed to it with your own system.  Net metering is a consumer-based renewable energy incentive, and policies vary by state.

So if I have a battery backup system am I still tied to the grid?

Often, there’s confusion around grid-tied systems and battery backup systems; people wonder if they are still tied to the grid if batteries are included in their installation. Solar energy systems with battery backup systems are still tied to the grid.  The advantage of a battery backup system is that  power can remain available if the grid power goes out.  While this can be important in some places, batteries are an additional expense, only last 5-10 years, require maintenance, decrease system efficiency, and result in a more complicated system.  If power outages are a large concern, it is most often more economical and reliable to purchase a generator instead of a battery backup solar energy system.