Grid-tie systems are 95% efficient and a net-metering program can bring you around $2,500 a year in some states. But will solar panels save you from a power outage in a grid-tie system? No, they won't. There are two reasons for this:
1. Grid safety
. When you produce more energy than you need, the inverter sends the surplus to the grid. When the grid goes down and electricians start fixing it, there must be no current in the power lines. This is why all inverters connected to the grid are designed to turn off automatically, so that workers can bring the power back safely.
2. Safety of your appliances
. During the day the power output of your array changes depending on the amount of sunlight the modules absorb. Normally, all the excess goes into the grid. If this uneven flow of energy from solar panels goes directly into the electrical system of the house, your appliances might break because the flow of electricity isn't consistent.
A while ago new grid-tie SMA inverters appeared
on the market with a feature of Secure Power Supply (SPS). These inverters can power the house with solar energy even during power outages. You don't need energy storage to use them.Thus, the general rule is that grid-tie solar systems don't function during a power outage, unless an inverter offers SPS. So the question stays: how to use solar panels during power outages? Is there a way?