If you’re thinking about installing a solar system to have power in a blackout, here are some facts to consider. There are many advantages to installing a grid-connected solar energy system. But, having full power to your home or business during a blackout is not one of them. You will need to take special steps for solar to work for you in a blackout.
In the event of a power outage, basic habits like charging a cell phone become essential. Most homeowners have no source of backup power when the grid goes down. Even homes with solar may lose power in the event of a grid outage if their system does not include some form of energy storage.
Solar rules and regulations vary widely from state to state. Are you located outside of Ohio? If so, check out a local installer near you to get more localized information. Find a solar installer near you here.
Does solar work in a power outage?
There are two reasons that ordinary grid-tied solar will not work during a grid failure. The first is a technical reason and the second is a safety and regulatory issue.
First and foremost is the technical reason.
The electronics that control a solar system constantly adjust voltage and current to keep the panels operating efficiently as the sunlight changes. To do this, the system produces quantities of power that aren’t dependent on how much your house is actually using in a given moment. In a grid-connected system, any excess power is put back onto the grid for others to use, and your utility credits you on your bill for that power.
Solar power output varies directly with sunlight levels. So, even if you disregard the need for efficiency, connecting this variable resource directly to your home’s electrical system would cause your lights to blink, damage your refrigerator, and wreak havoc on your computers and television.
The second reason that solar shuts down during a blackout is safety.
During a power outage, the power utility sends out repair crews to find and fix the points of failure. Linemen and women will be jeopardized if there is a local power generator (like a solar array) leaking power onto the grid lines. Therefore, utility rules mandate that in the event of a power outage, solar arrays must automatically shut down. Solar systems have detectors that sense whether power is coming across the grid, and whenever grid power is down, they automatically shut down too, to protect utility workers.
There are arguments for and against battery storage for PV solar systems. The biggest “for” argument is that battery backup will power your home or business during a blackout. The biggest “against” of battery storage is the cost, which can double the cost of your clean energy system. Batteries also compromise the “clean energy” aspect of solar—they are toxic and very costly to discard when no longer useful. Batteries have a relatively short life, compared to other solar system components; they are also very heavy and bulky, and require a lot of maintenance to perform at their best.
You are a good candidate for a backup battery system if you:
- Want to know that you will have seamless energy when the grid is down
- Experience frequent power outages
- Experience extreme weather conditions
- Have critical appliances at your home
Tesla Powerwall: Home Battery Storage
Powerwall is a home battery system that turns your home’s solar panels into an all-day resource. Daily it increases your self-consumption of solar. In the event of an outage, it offers reliable home backup power. With Powerwall, more of your home’s electricity use will come from solar, which enhances solar functionality, reduces energy costs and provides peace of mind to homeowners.
Powerwall allows you to store 14 kWh of energy and use that energy to run your home with solar during the night and back up your home in the event of a power outage.
The technology withing Powerwall is able to detect a grid outage, disconnect from the grid and bring power back to your home in a fraction of a second. That is over 100x faster than typical standby generators, and fast enough to keep your appliances running without interruption. You will not have to reset your clocks or your alarm. Powerwall can provide backup to your entire home. However, depending on the type of appliances at your home, we may recommend an essential load backup instead of whole home backup. Read more about Tesla here.
Right Sizing Your Backup System:
Whole Home Backup
If you’re interested in whole home backup, our Solar Designers can analyze your homes electric use patterns and the recommended number of Powerwall’s needed to keep all loads running. In some cases, an upgrade to your electrical panel may be needed and we will advise you if this is the case. You can add more Powerwall’s to keep your house operational longer during an outage.
Essential Load Backup
If your electrical situation doesn’t require whole home backup, we can backup select essential loads. Since lights and outlets require less energy, a single Powerwall will typically be enough.
New inverters offer some solar power in a blackout
We have been using SMA inverters for a long time—they are great products with high reliability.
Now, new technology developed for SMA’s Sunny Boy 3000TL-US/4000TL-US/5000TL-US models offers a partial solution to the grid power failure problem. These new inverters feature a secure power supply (SPS) that can connect to an external socket outlet. They provide up to 1,500W of daytime power when the sun is shining and the array is generating sufficient power in the event of a grid outage. This gives customers confidence that a small supply of electricity will be available, even when the grid is out and other solar PV systems are down. The bottom line is, with new technology, grid-connected solar can deliver a limited amount of electricity to your home or business during a power outage. This is a new development.
These new inverters address both of the technical and safety issues by creating a small, independent circuit entirely disconnected from the grid. The inverter controls the solar panel electrical output as an alternative to sending out variable power levels.
SMA inverters represent a compromise between solar owner’s desires for backup power and reluctance to make the upfront investment in a battery backup solution.
Is solar worth the money?
The ability to generate clean solar power during a blackout is an advantage of going solar.
- In the long run, solar power is economical. Solar panels and installation involve high initial expenses, but this cost is soon offset by savings on energy bills.
- Solar can increase the value of your home.
- With a grid connection and net-metering rules, your solar power system shares clean energy with the grid.
- Federal tax credits can offset 30% of your investment.
- Solar energy systems are safe, reliable, and durable—the panels are warranted for 25 years.
Your fuel is free once your initial investment in solar is paid off. With fossil fuel costs & utility rates predicted to rise, solar is good way to lock in long-term savings now.