One of the primary goals for most homeowners interested in solar power is the desire to have a renewable source of energy without being tied to the cost fluctuations and monthly bills of your local utility company. Unfortunately, many people have a misconception that in order to do that, they need to go “off the grid” and get a battery installed with the system to store solar power.
For most people, the option to have a grid-tied solar system will achieve the goals of generating your own power and ditching the utility company, but without the huge expense of battery storage. Here’s a quick overview of what that means and whether it’s the right choice for you.
HOW SOLAR SYSTEMS WORK
Residential solar systems work by capturing energy from the sun and storing that energy to power everything in your home. Since solar systems can only generate power when the sun is shining, that means the system isn’t working when the sun goes down or when there is excessive cloud cover. Since you use energy when the sun isn’t shining, every solar system needs to have a way to store energy when it’s available for use when it’s needed.
An off-grid system stores its excess energy in battery banks that are installed as part of your solar system. Battery banks are more expensive, though, so the only reasons that you absolutely need to get one are if you don’t have access to power lines (it’s mandatory in this situation), or you want to have backup power in case of a power outage at your local utility. It’s important to note that batteries also come with some energy loss; the typical lead-acid batteries used in off-grid systems are only about 80-90% efficient (you’ll automatically lose 10-20% of the energy you generate), and that efficiency declines over time.
The more common, and more cost-effective, option for most people is to get a grid-tied solar system. These are connected to your local utility power grid and as your system generates energy it “deposits” that energy into the grid. You get a credit for any deposited energy and can use those “credits” whenever you need them—a process called net settlement of energy. If you don’t use all the solar energy that your panels generate, your local energy company may even be willing to pay you for the excess.
A grid-tied system has no added installation costs, saves you the expense of installing a battery bank for storage—which can account for anywhere from 30% to 40% of the total cost of installing a new solar system—and provides you with an added layer of security in the event your solar equipment ever stops working.