Are Solar Batteries Worth It?


Enhancing your solar energy system's performance, whether by integrating a battery with a new solar setup or adding one to an existing system, offers a way to optimize your clean energy utilization both during the day and into the night. The combination of solar panels and energy storage allows you to operate in a self-consumption mode, allowing you to store surplus energy generated during the day in the battery. This stored energy can then be utilized to power your home during nighttime hours, reducing your reliance on the conventional utility grid.

The integration of energy storage with solar also holds significant advantages in terms of resilience during power disruptions. The escalating frequency of severe weather events, coupled with aging power grids and heightened wildfire risks, has led to more frequent power outages across the nation, including here in New Mexico. Traditional grid-tied solar systems are designed to disconnect during grid outages to prevent the back-feeding of power, which could pose risks to grid maintenance workers. However, by incorporating energy storage, you can keep your essential appliances powered, drawing upon the stored energy within the battery to maintain electricity supply during such times.

While the benefits of adopting energy storage are evident, you may still have some lingering inquiries before making this investment. Below, we address common questions that individuals considering energy storage alongside their solar systems often have:

1. Are Batteries Cost-Effective?

The average cost for a storage system is just below $1,400 per kWh. Consider the Tesla Powerwall, offering around 13.5 kWh of usable capacity, which translates to an approximate cost of $18,000, installed. Fortunately, as of 2023, you can benefit from the 30% Federal Investment Tax Credit, significantly reducing the price. At this time, New Mexico’s 10% Solar Market Development Tax Credit only applies to home solar system costs (not batteries).

Evaluating whether the added battery expense is worthwhile involves considering factors such as the frequency of power outages, your desire to rely less on the grid and more on clean energy, as well as what you could stand to lose during a prolonged outage. The reassurance of a dependable backup energy source for critical loads can make this investment particularly valuable. As battery prices continue to decline, retrofitting with a battery could be a viable future option if increased security through energy storage becomes a greater priority.

If your utility has time-of-use (TOU) rate structures where the energy can cost significantly more during high-demand periods at night, or if you don’t receive the benefit of net-metering, the economical benefit of solar batteries can be considerable. [Most electrical companies in New Mexico don’t utilize TOU rates and provide net-metering, so the batteries provide a smaller financial incentive, if any.]

2. What's the Lifespan of a Solar Battery?

The longevity of solar batteries hinges on various factors, beginning with the battery type and chemical makeup; Different battery chemistries have distinct lifespans. Lithium-ion batteries, like the Tesla Powerwall, are favored for solar storage due to their extended cycle life and user-friendliness compared to alternatives like lead-acid batteries (which we do not offer).

Cycle life refers to the number of charge-discharge cycles a battery can undergo before its capacity significantly diminishes. Lithium-ion batteries can withstand as many as 3,000 cycles, lasting up to 15 years or more. In contrast, a lead-acid battery can manage up to 1,000 cycles and generally lasts around 5 years or less.

3. Can a Battery Provide Whole-Home Backup?

Generally speaking, whole-home backup will require multiple batteries to accomplish and will depend on your unique power needs. Battery backup inverters may also struggle to sustain larger, high-power-consuming appliances such as Air Conditioning or deeper well pumps. While investing in multiple batteries could theoretically support whole-home energy needs, it could prove costly. Typically, one or two batteries provide enough support to keep essential functions operational, such as lighting, refrigeration, device charging, and routers. A smaller battery system can also be designed to provide emergency backup to critical loads.

4. Where to Install Solar Batteries in Your Home

You’ll want to ensure you have an appropriate/adequate location for a home battery-- a non-living space, indoors, that’s easily accessible (like a garage, basement, or larger utility room). It’s best if this location is near your main service panel. The National Fire Protection Association (NFPA), among other regulatory agencies, provides guidance and requirements for where a home battery is allowed to be placed. Don’t worry, Positive Energy Solar can help identify if you have a feasible area for your solar battery.

5. What Warranty Options Exist for Batteries?

The Tesla Powerwall, offered and installed by us, is covered by a 10-year manufacturer warranty. As a Tesla recommended installer, you’re in good hands and receive a high quality home battery installation by experienced professionals, supported by a 25-year workmanship warranty.

Whether you're contemplating a transition to solar with energy storage or pondering the addition of a battery to your existing setup, don't hesitate to reach out to us. Our team is dedicated to addressing your queries and helping you determine whether energy storage aligns with your needs and objectives.