Your Battery Questions Answered

Solar panels + storage = the future of consumer empowered energy.

The Green Energy Revolution is here: According to The Wall Street Journal, global investment in renewables was over double that of fossil fuels in 2016 and the momentum in our energy transformation continues to grow. As solar and wind technologies are reaching new peaks in applicability and efficiency, their last limiting factor is being cured by advancements in energy storage, the final piece of the modern energy puzzle.

After a tumultuous winter on our California Central Coast with several natural disasters causing prolonged power outages, residential and commercial battery inquiries are on the rise. We’ve got your questions covered from how these systems work, to the options available, and even the current incentives in place.

Batteries 101battery solar charge

How exactly do batteries work?

You can compare home energy storage to a backup generator: when the power goes out but your fridge is full of perishables and your phone is at 1%, you want a Plan B in place. Instead of plugging into a disruptively noisy generator that runs on fossil fuels, your sleek and silent battery would kick in. This can be charged by the electricity from your solar panels or from the grid. (Yes, this means that you can install energy storage without solar panels as well.)

When the power comes back on, your battery will recharge for next time. You can choose the amount of battery storage to power your must-have appliances and electronics for a designated amount of time.

Will my solar panels power my home during the day in a power outage without a battery?

If your solar system is tied to the grid (which is usually the case), there is an automatic shutdown in place during an outage. This is a safety measure to prevent electricity from flowing into the grid while workers are fixing the power lines. Unfortunately this means that your home will not be able to utilize the electricity generated by your solar panels while the grid is down.

Your panels will continue to produce power during an outage if they are connected to a battery backup system and an inverter-charger, because the electric circuit will be on a closed loop separate from the grid. During the outage, your battery and panels would work together to supply your home with power, day and night. Hooray! No spoiled food for you.

 

How much battery power do I need?

To determine the size of energy storage you need, you must first consider two things:

battery solar off grid

  • What is the purpose of using batteries? (Most commonly for emergency backup, to avoid paying peak rates from the grid, or to go completely off-grid.)
  • What electronic appliances would be deemed essential in the case of a blackout? Items like cell phones, laptops, refrigerators, internet routers, and a few lights usually make the list, but if your house is more “teched out” than most, you have extra considerations to take, such as electric vehicle gates, alarm systems, and pool covers.

Once you’ve determined the “critical loads” of your battery backup system, you should also consider how many hours per day they need to receive power. We’ll help you do the math to determine exactly how much backup power you need.

 

Isn’t it better to go completely off the grid?

Off-grid independence certainly has its perks: no monthly charges from the utility for using the grid and the ability to host your neighbors for dinner during a blackout. The catch is that you have to have a large enough storage supply to cover several days in case of a storm or other emergency. This gets costly very quickly. A grid-tied solar system with a battery backup will cover all your bases and ultimately be a more profitable investment.

Off-grid applications are best for smaller buildings that have minimal consumption and/or have limited access to the grid.

 

Choosing the Right Battery

What’s the deal with the Powerwall? Is that the best option out there?

The Tesla-SolarCity alliance is a well-oiled marketing machine and they’ve done wonders in bringing attention to energy storage with their Powerwall product. They are however not the first nor only company to produce batteries for residential and commercial applications. If you’d like to learn more about how different battery manufacturers stack up, we can help.

What are batteries made of?

There are many types of batteries on the market now, ranging from sealed or ventilated lead acid, the “old school” rechargeable battery, to variations of the lithium ion battery, which is the type of battery you’ll find in your smartphone and laptop.

It is important to note that not all batteries are created equal.  Some require more maintenance than others, and some chemistries are more harmful to the environment than others. In today’s battery market, you’ll mostly find lithium ion batteries, but there are many chemical configurations of these, varying in both quality and safety:

battery energy storage comparison lithium ion batteries

The Tesla Powerwall and LG Chem batteries have the NMC configuration, where Simpliphi and Sonnen have the safer, more eco-friendly LFP chemistry. As a sustainably minded business, we have decided to exclusively install batteries with lithium iron phosphate.

 

Getting the Most Out of Your Battery Investment

 

Does the ITC include batteries?

solar battery itc energy storage tax credit

The Federal Investment Tax Credit can save consumers up to 30% of the total cost of their solar system, optimizing their investment. Batteries are eligible for the tax credit but with a few stipulations:

-The battery must be charged by a renewable energy source (i.e. solar panels) at least 75% of the time.

-The exact value of the credit depends on how the battery is charged. If the battery is charged by your solar panels 100% of the time, you can utilize the entire 30% tax credit. If not, the credit is proportioned to the renewable energy the battery receives.

 

 

What’s the status of the Self Generation Incentive Program in California?

The Self Generation Incentive Program, or SGIP, is a statewide incentive for energy storage installation, and can dramatically reduce the upfront cost of your battery. As of June 15, 2018, both Southern California Edison (SCE) and Pacific Gas and Electric (PG&E) are at Step 3 Incentive Rates: $350/kWh for residential energy storage less than 10kW. If you install batteries, be assured that Brighten Solar Co’s expert financial team will apply for all available incentives for you to maximize your return on investment. To see the current status of the SGIP, click here.

For further reading about batteries, please download our free white paper: 

Do I need batteries with my solar system?

Learn the basics of installing a solar system with batteries with our white paper download.