top of page

Q&A with Fortress Power

Early in 2018, Fortress Power released two energy storage systems in the United States – a 10 kilowatt-hour (kWh) and a 15 kWh model. Their foray into an increasingly packed residential storage system market is with a different type of chemistry – lithium ferrite phosphate – than many other options available on the market. EnergySage sat down for a Q&A with Fortress Power to learn more about the company, why customers should consider energy storage, and how Fortress Power batteries differ from other brands in the market. (Interview has been edited for brevity and clarity.) Find out what solar + storage costs in your area in 2023

An overview of Fortress Power

[ES] Tell us about the history of Fortress Power. What’s the background of the company and how have you grown so far?

[FP] Fortress Power was founded in 2016 by a group of solar veterans. Many of our employees have designed and installed solar PV and battery energy storage for over 10 years. In 2016 our president, Barry Moore, was contacted by a municipal entity to design off-grid solar-plus-storage systems to power railway gears and control lights. Their problem? Existing enclosures were too small to fit large lead-acid batteries. Our team built the municipal entity a customized battery bank from Lithium Iron Phosphate battery cells from Asia, safely designing a solution that fit their space and energy needs. From there, we established our headquarters in Southampton, PA, with a mission to provide clean, affordable and secure energy to millions of homes and businesses. We have over 20 employees in our 30,000 square foot facility, which is powered by a 100-kilowatt rooftop solar array and backed up by our own Fortress Batteries. Our products are engineered and designed here in the U.S and assembled in Asia since that region possesses the world’s most lithium manufacturing capacity.

[ES] What are your primary products for homeowners? How do they compare with other energy storage solutions on the market?

[FP] Currently, we design 10- and 15-kilowatt-hour Lithium Iron (Ferro) Phosphate batteries for the residential and small commercial markets here in North America. The batteries, named the LFP-10 and LFP-15, are compact and modular, and the total storage from Fortress Power batteries is scalable to 120 kilowatt-hours by stacking up to eight units in parallel. Our smart Battery Management System allows for fast-charging and a large discharge current to allow you to turn on electricity-intensive appliances when the grid is down.

Unlike batteries from competitors that contain easily ignitable cobalt, Fortress Power uses a safe Lithium Iron (Ferro) Phosphate technology. Additionally, our Lithium Iron Phosphate batteries deliver more than twice as many cycles as a Tesla Lithium Ion battery does, as calculated based upon total guaranteed energy output. What’s more, Lithium Iron Phosphate batteries have a wider operating temperature range (-4 to 140 F) to keep your home powered in extreme weather events.

Our battery packs are affordable and comparative to our competitors on an all-in basis.* Where our LFP-10 and LFP-15 kilowatt-hour batteries shine is in a cost per cycle comparison, given that Fortress Power batteries last for more cycles than competitors. In fact, our batteries are warrantied for 10 years and a guarantee of 6,000 cycles.

The future of the solar + storage industry

[ES] Why do/should customers be considering storage plus solar?

[FP] First, many homeowners are not aware that a traditional solar PV system shuts down when the grid goes off. An energy storage system can allow the solar system to continue operating during any power outages.

What’s more, energy storage can also help residential solar customers maximize the benefit of their solar production. In some states, utilities and state regulations don’t allow for the export of solar production onto the grid. In those situations, an energy storage system can store the solar power produced during the day for use later in the day.

Another reason to consider energy storage is to help save money on your monthly electricity bill. If you are on a certain type of utility electricity rate, such as a time-of-use rate, energy storage can store power from either the grid or your solar panels during off-peak periods to then supply your home during peak periods when purchasing from the grid would be more expensive.

[ES] What questions are customers not yet considering that they should be when making a decision about a home energy storage solution?

[FP] A key component of the energy storage purchasing decision that is not yet widely discussed by potential customers is that energy storage systems should be sized to power a household’s essential loads – household appliances such as refrigerators, lights, water, and sump pumps, or computers and phones – and not the entire house during the power outages. Many customers we talk to want to know how long the battery bank will last in the event of the outage, how many circuits can be powered by the battery, and how much the system costs up front. But we don’t often hear questions about the impact of purchasing energy storage systems with different types of battery chemistry. Homeowners researching storage systems can check the battery chemistry with the manufacturer first before they make a purchase to ensure they understand the power, lifetime degradation and safety implications of different chemistries.

[ES] Where do you see the energy storage industry moving in the next year and a half? What could impact that growth?

[FP] We see the energy storage market growing at an unprecedented pace for the industry over the next 6 to 18 months. We expect costs will continue to drop, as well as to see more “plug-and-play” solutions become available. Battery manufacturers will necessarily look to more cost competitive and more user-friendly products to differentiate themselves.

From our interactions with customers, we see several roadblocks for greater adoption of storage: high costs, not enough skilled installers of storage and a lack of user-friendly storage-proposal tools or calculators. Nevertheless, we predict the customer rationale for purchasing energy storage solutions will strengthen as we see stronger and more frequent storms, rising electricity costs in many parts of the country, increased adoption of time-of-use rates, and more and more state and federal incentives to purchase storage.

Fortress Power looking forward

[ES] What’s next for Fortress Power?

[FP] We plan to launch an innovative, new product – called the eVault LFP-15 kilowatt-hour – in December. We’ve designed this new product to provide an even higher level of transparency to our customers. The battery comes with an LCD monitor that shows the battery’s state of charge, voltage, temperature, and cycles. The new eVault will harness our Battery Management System to continue to allow customers to connect 8 batteries in parallel, achieving a total storage capacity of 120 kilowatt-hours. Also, this software allows each battery to supply 8.2 kilowatts of discharge power and up to 20 kilowatts of surge power, a big step above the market standard.

storage content


bottom of page