BESS Solutions 101: Everything You Need to Know

The case for urgency

We are facing an unprecedented moment in the energy landscape: electricity demand is rising faster than it has in decades, driven by the explosive growth in datacenters needed for energy-intensive technologies like generative AI and increased manufacturing activity. A recent report by the National Electrical Manufacturers Association (NEMA) projects that U.S. electricity demand will grow by 2% annually, resulting in an overall increase of about 50% by 2050.

To meet this rising demand while addressing the challenges of an aging grid, we need to expand energy supply quickly and sustainably. Clean energy sources like solar will play a major role. It’s fast, cost-effective, and easy-to-deploy. It’s no surprise that solar has been growing rapidly and accounted for 66% of all new electricity-generating capacity added to the U.S. grid in 2024, according to Solar Energy Industries Association (SEIA).

Growth projections for BESS

However, solar alone isn’t enough. Its intermittency makes energy storage essential for delivering power reliably, whenever and wherever it’s needed. This growing demand for energy storage is already being reflected in market trends. The latest U.S. Energy Storage Monitor report by the American Clean Power Association (ACP) and Wood Mackenzie shows that the U.S. energy storage market set a new record in 2024 with 12.3 gigawatts (GW) of installations. NEMA estimates that storage capacity connected to the U.S. grid—meaning the amount of electricity that battery systems can store and later discharge—will grow by 1,100% over the next 15 years. This growth underscores how central BESS will be in accelerating electrification and strengthening the nation’s energy independence.

In this blog, we will discuss the significance of BESS, and how Shoals is redefining energy storage with innovative, industrial-grade solutions. We’ll also spotlight our modular BESS Recombiner—a scalable, plug-and-play solution designed for easy assembly and customization to meet each project’s unique needs.

What is BESS and what does it do?

BESS definition and core components

Battery Energy Storage Systems (BESS) are technologies that capture and store excess electricity—often from renewable sources like solar—for use when it’s needed most. At their core, BESS units typically consist of battery cells, inverters to convert energy between AC and DC, thermal management systems to maintain safe operating temperatures, protective enclosures, and the electrical balance of systems (EBOS) components that tie it all together. This infrastructure allows energy to be stored during periods of low demand or high generation and discharged during peak usage, grid stress, or outages.

The diagram shows what Shoals’ BESS Recombiner does.

BESS benefits

The benefits of BESS are wide-ranging and essential for modern energy systems. Storage turns solar into a true around-the-clock resource. BESS smooths out the natural intermittency of solar, ensuring power is available even when the sun isn’t shining.

• Grid Stabilization: BESS supports grid stability by rapidly absorbing or discharging energy to balance supply and demand, helping maintain consistent frequency and voltage levels.
• Peak Shaving: BESS reduces the need for fossil-fuel peaker power plants, which are older, less efficient, and more polluting. These plants operate infrequently and have higher operational costs.
• Backup Power: In the event of outages, BESS provides immediate power, enhancing resilience for residential and commercial users.
• Time-of-Use Optimization & Energy Arbitrage: BESS enables energy to be stored when demand and prices are low and dispatched when they are high. This improves efficiency, reduces costs, and allows for strategic energy management.

BESS solutions presented by Shoals at RE+ trade show in September 2024.

BESS solutions from Shoals

At Shoals, we recognize the challenges that EPCs, developers, owners, and IPPs face every day. With decades of experience simplifying PV electrical systems, we bring that same expertise to BESS. We understand how important it is to fast-track deployment, reduce complexity, and deliver high-quality systems that stand the test of time. Our BESS solutions are built with a focus on:

• High Quality: Built for industrial-grade durability and performance, with top-tier materials and rigorous testing.
• Simplicity: Modular and pre-engineered for quick, error-free installation.
• Sustainability: Designed to reduce waste and maximize long-term efficiency.

Shoals’ approach to BESS

Our approach not only streamlines deployment but also results in significant savings on labor and materials, addressing two critical pain points in the industry. Here is the full range of BESS solutions that we offer to our customers:

• Recombiner collects and combines inputs from solar arrays, BESS units, other DC microgrid components, or a combination of these sources, consolidating them into a single output to the inverter. By streamlining inputs, BESS recombiner helps reduce the overall inverter count on-site, improving system efficiency and simplifying design. It allows charging the BESS from renewable sources and discharging the BESS to provide consistent power to the grid. It optimizes site layouts and moves the DC recombiner from the BESS to a centralized location.
• Disconnect Switches are used to isolate and remove power from the BESS container. Using disconnects mounted away from the BESS containers allows for centralized location of disconnecting, reducing O&M time.
• Wiring Solutions are custom wire harnesses or jumpers, simplifying wiring and installation tasks. Manufactured in a facility with stringent quality standards, these solutions minimize onsite labor, leading to reduced project expenses, faster deployment, and elimination of in-field wiring errors.

Shoals BESS Recombiner – Simplifying battery storage

What is a BESS Recombiner from Shoals?

Recombiner boxes play a crucial role in the electrical architecture of BESS, acting as the central point where current from multiple battery racks or strings is safely combined before being sent to the inverter. Just as BESS relies on batteries to store energy, it relies on recombiners to manage and route that energy efficiently and safely. Without this step, the flow of high currents from multiple sources can become difficult to control, increasing risks and complexity in the system.

What does BESS Recombiner do?

A well-designed BESS recombiner streamlines the wiring, reduces on-site labor, and improves overall safety and reliability. It’s especially important in large-scale installations, where managing multiple battery enclosures without a centralized, modular solution can quickly become a logistical and engineering headache. Think of the recombiner box as the nervous system junction of your energy storage project—bringing together all the electrical inputs into one coordinated, controlled output. It reduces the number of inverters needed on site. When built with industrial-grade components and designed for modularity , BESS recombiner not only makes installation faster and cleaner but also simplifies maintenance and scalability for future system expansions.

Our BESS Recombiner’s special features set it apart

We fully customize our recombiners to support many combinations of the battery power levels. Our recombiners have three (3) standard current levels, 1200A, 2000A, 4000A all rated at 1500VDC and can be used in AC coupled or DC coupled site configurations. They are fully independent of battery technology.  There is a wide range of fused battery connections from 80A-800A with each connection capable of its own individual fuse rating. There are up to eight (8) battery connections per cabinet, expandable up to 3 cabinets wide. The Recombiner is UL 1741 certified for both 1200A and 2000A configurations, with a 4000A version built to the UL 1741 standard.

Which BESS solution is right for your project?

When considering which BESS Recombiner solution is right for your project, it all comes down to the type of energy storage system you’re deploying. If you’re working with containerized, all-in-one AC battery storage systems, our recombiners may not be necessary, since many AC coupled setups have internal wiring and power conversion built in. But if your application is DC-coupled, with separate battery racks and external inverters, that’s where our industrial-grade recombiner solutions come in. Designed specifically for high-performance DC BESS systems, our recombiners streamline wiring, improve safety, and simplify installation, making them the right choice for scalable, field-assembled energy storage projects.

Driving innovation in the energy space

Innovation is at the core of everything we do at Shoals. From our Big Lead Assembly (BLA) to our latest BESS solutions, we’re always pushing the boundaries to simplify, optimize, and future-proof energy systems. We invest in R&D, embrace cutting-edge technologies, and maintain a culture of continuous improvement to stay ahead of industry needs.

We’re proud to be known for our disruptive thinking and customer-first mindset. Our team is constantly iterating, testing, and refining to help our partners meet the demands of a rapidly evolving clean energy landscape.

Conclusion

As demand for clean, reliable power continues to surge, BESS stands at the heart of the energy transition, and getting it right is more critical than ever. The way we store and manage energy will define the resilience and flexibility of tomorrow’s grid.

Shoals is meeting this challenge with modular, industrial-grade BESS solutions that allow customers to build smarter, safer, and faster—without compromising on quality or performance. Our BESS Recombiner exemplifies the power of simplicity, durability, and thoughtful engineering. Together, we can reimagine energy storage—piece by piece—and build a stronger energy future.