Solar energy systems deliver clean, cheap, renewable energy to homeowners. But when storms and earthquakes knock out power for days or even weeks, most systems are designed to shut down to prevent sending power back to the grid in order to protect utility line workers.
In Washington and Oregon, many homeowners turn to generators to provide power during blackouts. But generators are noisy and smelly–and it can be challenging to get fuel in hard weather. And fuel-powered generators have a definite impact on the environment.
Now there is another option: clean, safe, recyclable batteries. These next generation batteries are perfect for residential emergency backup.
Sonnen is a programmable, indoor-ready storage system that is recharged by your home’s solar PV system every day. That means that during a power outage, Sonnen will allow your home to function, even at night.
The system is also expandable if your needs change. It comes with free online/mobile monitoring, and best of all, is eligible for the 30 percent Federal Income Tax Credit, a dollar-for-dollar reduction of the income tax you owe.
We’re still waiting for the Powerwall to become available to installers in the Northwest. While Tesla made headlines when it announced the second generation of its storage system, the company is only beginning to install the units. We continue to monitor the emerging battery market–including the Outback battery offerings–and will update you when different quality options are ready to be installed.
In the meantime, here is a chart comparing Sonnen, Powerwall, and Outback offerings.
Usable energy storage
10 year/10,000 cycles
Up to 4 years
Supports backup generator
No (per Tesla)
Lithium Iron Phosphate (LiFePo)
Nickel Manganese Cobalt (NMC)
UL 9540 safety certification for energy storage**
How far can batteries be discharged?***
No more than 50% discharge recommended or damage can occur
No, but expected in 2017
Includes UL certified Automatic Transfer Switch for grid-down operation****
With optional GS Load Center
*Batteries use different methods for storing energy. Different elements are combined to create the ability to store energy. Each formulation has its advantages and disadvantages. Talk to our design consultants to learn more.
**Indicates whether or not the battery has been certified by the world’s leader in safety science and safety certification.
***Lithium Ion batteries are more tolerant of deep discharges. Deeply discharging lead acid batteries shortens their lifespan greatly.
****To safely allow you to power your home during an outage, we have to make sure power isn’t sent back out onto the grid and potentially harm line workers trying to restore service. An Automatic Transfer Switch automatically senses the grid has gone down and safely isolates your home from the grid and your battery system will provide power instead.
A&R Solar recently installed this Sonnen battery for homeowners in Edmonds, Washington. The couple determined that they want to make sure they have power during any outages. The system will charge during the day to ensure they have power at night.
Read more about why they chose to invest in a Sonnen system, including how they feel about having this security against future blackouts.
Beyond the peace of mind their system gives them about having power during an outage, batteries can also protect your solar investment against potential changes to utility rates. Many states have enacted time of use charges and net metering policy changes, and some industry insiders believe Washington and Oregon could someday follow.
Curious about how a battery storage system might be right for your home? Call us at 206-707-9937 or 503-420-8680, or fill out the form below.
“For the first time, we’re fully covered in the event of a grid power outage. One of the first questions that I asked A&R was how long I could subsist on the battery power. It hadn’t dawned on me that it could be indefinitely, since the solar array continues to charge the batteries each day. That kind of energy freedom and independence is very comforting.”