With our reliance on electricity, even brief outages can be disruptive. As a result, more homeowners are exploring battery-powered backup systems to stay connected during power interruptions. Battery energy storage systems (BESSs) store energy for later use and can provide backup power, reduce energy costs and support demand.

How does a BESS work?

Systems can be installed in residential, commercial and utility-scale environments. Batteries can even be installed in remote areas where the grid may be unstable or limited. The base capacity for residential systems ranges from 10 to 13.5 kWh, which can power an average home. Your energy needs will vary depending on the appliances you have, how often they run and how much backup power you want.

BESS core components

Battery — The battery stores energy and releases it when needed. There are two main types used in residential installations. Lead-acid is the oldest and cheapest storage technology and is used in small projects with a lifespan of three to seven years. Lithium-ion is the most common for home systems, with a lifespan of five to 20 years. The latter has higher energy density, faster charging capabilities and is lighter and more compact than lead-acid batteries.

Battery management system — The system monitors battery performance to prevent damage from overcharging, over-discharging, overheating and short-circuiting. It also provides information on the battery’s charge level, health and temperature.

Monitoring system — The monitoring system provides data about the performance of the BESS, such as energy consumption, charge and system efficiency. This system also may provide alerts if issues are detected.

Inverter — This converts the direct current (DC) electricity from the battery into alternating current (AC) electricity, which is used by home appliances and the grid. Stand-alone inverters are used for off-grid setups or as backup power.

What are the safety risks?

According to the National Fire Protection Association, four situations can cause batteries to fail, which could lead to dangerous conditions. These include mechanical abuse (the battery is dropped, crushed or penetrated), thermal abuse (the battery is exposed to external heat sources), electrical abuse (the battery is overcharged, charged too quickly, discharged too fast or the voltage is too high) and environmental impacts (earthquakes, rodents damaging the wires, extreme heat and floods).

The most significant safety concern is that these can cause thermal runaway. This is rare and happens when heat builds up in the battery cell faster than it dissipates.

Installing a BESS safely

Purchase it from a reputable manufacturer and hire a licensed electrician. Ensure compatibility among the battery, inverter, controller and renewable system, if using one. Install it in an area recommended by the manufacturer. Use nonflammable materials like masonry or metal, and follow the manufacturer’s clearance recommendation or maintain a 3-foot clearance around the BESS.

Consider environmental hazards like flooding, extreme temperatures, snow accumulation or vehicle impact, and keep the system away from heating equipment. Ensure the area is well-ventilated, and check if permits are needed.

Ongoing safety tips

Register your BESS with the manufacturer and connect to Wi-Fi for monitoring. Stay updated on firmware and safety recalls. Regularly test smoke detectors and maintain clearance. Never use a fire extinguisher on a BESS fire. If you notice smoke, gas or chemical odors, evacuate immediately and call 911.

Always work with certified manufacturers and installers to ensure safety, and contact your co-op early in the process to check for specific requirements for installation, the grid interconnection process and available incentives.

To learn more about electrical safety, visit SafeElectricity.org.