There are two main types of solar power systems. The most common is called grid inter-tie. This means you power your home using solar energy during the day, but you’re still on the grid at night. Since you’re connected to the grid, if you create any surplus power, you actually feed it back into the system.

Since you’re not generating your own power at night, you won’t be making money off your solar power by feeding the grid. However, you can power yourself by day and any excess power you generate helps you save money on the power you use at night.

A grid inter–tie system can cut down on your total electrical bill while also ensuring you have daytime power available during a disaster, brownout, or emergency situation. If you want to go off the grid for full energy independence, you’ll need more than the solar cells. You’ll need a rechargeable battery array.

Without a battery array, you can’t store any electrical energy. You don’t want your entire house to go dark when the sun goes down, so in addition to the solar cells you’re going to need some chargeable batteries. Getting the power in and out of those batteries requires a little extra equipment.