When the power goes out, do solar homes keep the lights on? That depends on what type of system you have, and what equipment is installed.
Grid-Tied Solar Systems
If you just have solar panels and an inverter, you likely have a grid-tied system. This is the most common type of installation because it offers the best return on investment. A grid-tied system works by monitoring the voltage put out by the utility company and mirroring that same voltage and frequency, allowing it to seamlessly provide power to your home.
However, during a power outage, there’s no utility voltage for the solar inverter to match. As a result, the inverter stops producing power. This is a safety feature built into the electric code that is designed to protect utility workers, ensuring that solar energy is not sent back through the grid during repairs on downed lines.
Why Have Solar If It Doesn’t Work During an Outage?
While it may seem irritating not to have energy when the sun is shinging and the grid is down, grid-tied solar systems offer significant benefits:
- Environmental Impact: Solar energy is a clean, renewable source of power. Using solar panels reduces your carbon footprint and helps combat climate change. Over its lifetime, a typical residential solar system can offset tons of CO2 emissions.
- Cost-Effectiveness: Grid-tied systems are the most cost-effective option for homeowners. They add value to your home, reduce energy bills, and can pay for themselves many times over through savings and incentives.
Battery Backup for Solar Systems
If maintaining power during a grid outage is important to you, consider adding a solar battery. Solar systems with batteries can keep your home powered by disconnecting from the grid using a controller or transfer switch. These systems can charge your battery and power your home simultaneously during the day. At night or when solar production is low, the battery supplies power to your home.
Modern batteries like the Enphase IQ 5P and Tesla Powerwall 3 are designed to provide ample power to essential circuits in your home during outages. Batteries like the 5P or Powerwall 3 can take over power so quickly that the lights may not even dim, and your TV/ internet will stay powered during the changeover. It’s also a great feeling knowing that your home is being powered by clean energy, when the utility power is down.
It sounds like battery-backup is great, why doesn’t everyone have it?
Cost. While the IRS did change its rules to make it easier to claim the 30% tax credit on solar batteries, solar systems with batteries don’t save any more money than a grid-tied system. The net-metering laws in Virginia are still strong (at the time of writing), so it’s not necessary to self-consume your solar energy, like it is in California or other markets. So if you want backup, that extra cost is all for functionality.
On the plus side, modern batteries are sealed, and have battery management systems built-in, so they don’t need regular maintenance, which is a major advantage over generators. In 2024 we’ve seen a huge uptick in the adoption of solar batteries– We’re your local Charlottesville solar installer, so if you are considering solar, make sure to get a quote from us!
Generators vs. Solar Batteries
When deciding between a generator and solar batteries, consider your goals and situation:
- Solar Batteries: Ideal if you already have or are planning to install solar panels. They are low maintenance and can power essential loads indefinitely when paired with solar panels.
- Generators: Suitable for providing a lot of power for short periods. If you have power-hungry appliances or a large service panel (like a 400A service), a generator might be more practical.
Generators require regular maintenance, fuel, and management, whereas batteries, especially when paired with solar, offer a more seamless and sustainable solution for backup power.
