Should You Get Battery Storage for Your Solar System


Battery storage systems help property owners take full advantage of the power production of their solar system. Without a battery storage system, the power would fade as soon as the sun set. Beyond that primary role, the question about battery storage systems become more complicated. This guide helps you ask the questions that apply to your solar needs and provides some resources that help you answer those questions. 

Two Personas - Those that have and those that might. 

There are two types of readers who should use this guide. They are the people who already have a solar system and those who are researching whether or not solar is a good fit for their home or business. 

Those That Have: If you already have a solar system installed on your home or business, then you have a battery storage system in place. The questions that you should ask are:

There are many reasons why the energy demands of a home or business with an existing solar system might change. A good example is a home that adds a swimming pool. A solar pool heater makes owning a pool more economical. For a business, adding new HVAC systems might increase the energy demands for an existing solar system. 

Those that Might: If you are in the process of determining whether or not solar is a good option for you, then some of the questions that you should consider are:

There are a lot of companies with solar panels for sale. However, it is not just the solar panels that you buy that makes a solar system efficient. Considerations include the efficiency of each type of solar power inverter - turns DC energy to AC energy - and the storage capacity of the battery system. There are two primary types of battery systems. Those Lithium-Ion and Lead-Acid. 

How Much Energy Storage Does Your Property Need?

Before you ask, "how many solar panels do I need," figure out how much energy you need right now and in the foreseeable future. Even across the most popular solar brands, there are differences in solar panel cost, solar panel efficiency, and installation. By knowing your energy need you can make a more informed decision about: which system fits your needs, the number of solar panels you will need, which type of solar panels work best for you, and how much the actual cost is for your project. 

Tip: You might not need more solar panels. Instead, you might require more battery storage. If your solar system installer matched your battery storage to your energy needs, your solar system might produce more energy than it stores.  You might just need an additional solar battery. This is a great consideration for both those with existing systems and those people reaching solar for their homes or businesses. Another consideration is that if your system is more than five years old, then the batteries in the energy storage system might require maintenance or even replacement. While replacing batteries is expensive, it is also an opportunity because technology improves your options for solar batteries. 

The reason this tip is important is that in 2017 the average cost for solar panel and installation ranged from $2.87 and $3.85 per watt. [1] If you don't need additional panels, then your cost might drop for a new install or for an add-on installation. Keep in mind that solar tax credit program ranges from $6.800 to $3,400 on average per installation. You can stretch those incentives by paying close attention to:

Another question to ask yourself is whether a solar generator will solve your energy needs. Solar generators are power generators, but instead of using gas or diesel as a fuel, they use a solar panel. If your list of solar energy pros and cons involves finding a solution for when traditional electricity is not available, then a solar generator might meet your needs. Again, the answer to that question is how much energy do you need?

Solar Energy Facts

1. Soft Costs Keep Solar Energy System Costs High -According to the Office of Energy Efficiency & Renewable Energy 64 percent of the cost of a residential solar system (including installation) is made up of soft costs. That means that 36 percent of the total cost that you pay is for the solar system and the rest goes into fees such as:

While the cost of the physical parts of a solar energy system become more affordable, the soft costs are holding steady.[2

2. One Million Homes in the US have Solar Energy Systems

3. The Average Cost of a Solar System is $16,800 - Before tax credits reduce the cost for a 5kW system. [1]

4. Solar Panels are not the only way to go solar. Thin films [3] make it possible for solar collectors to double as usable products such as roof shingles. 

Biggest Solar Companies

Solar City ranks in the top slot for residential solar companies. They have been around since 2006, employ about 14K people, and their solar installations produce 2,184,00 megawatts. 

Vivint Solar out of Utah ranks as the second largest residential solar company. They began in 2011 and currently employ about 4K people. Their solar installations produce 459 megawatts of energy - half of those installations occured in 2015. The company is growing quickly.

While Solar City and Vivint are large companies, small companies like Solar Plexus offer consumers services that rival that of bigger companies. Solar Plexus is Montana-based and began installing solar systems in 1994. They specialize in renewable energies that include solar, but also hydro and wind too. That is important in case solar is not the answer for your alternative energy needs. 

Typical Costs for Battery Solutions

There are a few types of batteries available. The two most common are lithium-ion and lead-acid batteries.

Lithium-Ion — In fact, Tesla offers a Powerwall battery system that starts at $3,000 and is small and scalable. It offers around 92 percent efficiency and manages 350-450 volts while weighing just 100 kg. They have an assumed cost of $300 per kWh with the expectation that fewer replacements over the systems lifecycle are needed. [4]

Lead Acid — Lead Acid batteries are much more affordable and start around $425. While each battery is small, a battery room is needed. They hold 1,660 kWh. They have an assumed cost per kWh of $255. [4]

Is Solar Worth It?

In 2016, the average U.S household spent around $1,400 for a year's worth of electricity and used around 11K kWh of energy. To find out if a solar energy system is worth it to for your property determine the following.

If you'd like a generalized cheat sheet by state, then the 2017 Solar Panel Savings Estimated by State Table is a great resource. For example, in California, the average cost of a five kW solar energy system or one of the 5 KW solar panel kits is around $13,370. The average electricity rate in CA is $0.1822/kWh, and the estimated 20-year savings is $28,360. [5]For most households, with the property owner owning the solar system, solar becomes very much worth the cost. 

Further Education:

[1] How much do solar panels cost in the U.S.? - EnergySage

[2] Soft Costs 101: The Key to Achieving Cheaper Solar Energy - Office of Energy Efficiency & Renewable Energy

[3] Small Solar Electric Systems -

[4] Economic Analysis Case Studies of Battery Energy Storage with SAM - National Renewable Energy Laboratory. 

[5] How Much Do Solar Panels Save? - EnergySage


[1] How much do solar panels cost in the U.S.? - EnergySage

[2] Soft Costs 101: The Key to Achieving Cheaper Solar Energy - Office of Energy Efficiency & Renewable Energy

[3] Small Solar Electric Systems -

[4] Economic Analysis Case Studies of Battery Energy Storage with SAM - National Renewable Energy Laboratory. 

[5] How Much Do Solar Panels Save? - EnergySage