Battery Storage Basics

Are battery-powered home energy systems the right choice for you?

With our growing 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.

Benefits of energy storage include:

• Cost savings: They can provide stored energy during expensive peak hours and recharge when costs are lower.
• Demand management: They help balance energy demand by charging when demand is low and discharging when it’s high.
• Backup power: They provide backup energy during outages and blackouts. They can replace diesel powered generators, offering an environmentally friendly back up source.
• Grid Support: They ease grid pressure during high-demand situations including extreme weather events.

Your guide to battery energy storage systems: basics, benefits and safety

Battery energy storage systems (BESSs), devices that store energy for later use, are gaining popularity due to their ability to provide backup power, reduce energy costs and support the electricity demand.

And since BESSs can store excess energy, they can be paired with renewable energy sources to provide reliable energy, given that renewable energy sources like solar and wind depend on natural elements that don’t always match energy demand.

If you are considering adding a BESS system that ties into the power grid, contact your electric utility early in the process to coordinate safe and proper connection to the energy grid.

How does a battery energy storage system work?

Systems can be installed in residential, commercial and utility scale environments. Batteries can even be installed in remote and rural 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. Appliances such as air conditioners and water heaters may drain the capacity quicker and you may want to disconnect them during an outage. Check with your utility about specific system requirements.

The core components of a residential BESS are:

Battery

The battery stores the energy generated from renewable sources 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 type for home systems, with a lifespan of five to 20 years. They have a higher energy density, faster charging capabilities and are lighter and more compact than lead-acid batteries.

Battery management system (BMS)

• 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, helping to maintain its longevity and ensure safety.

Monitoring system

• The monitoring system provides data about the performance of the BESS such as the energy consumption, charge and system efficiency. This system provides data and may provide alerts if issues are detected. It doesn’t directly manage or control battery operations like the BMS.

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. Grid-tie inverters sync with the grid, allowing electricity to flow back when demand is low or during peak pricing.

Safe installation:

• Purchase from a reputable, certified manufacturer and hire a licensed electrician who follows the manufacturer’s instructions.
• Ensure compatibility among the battery, inverter, controller and solar system (if using one).
• Install in an attached or detached garage, utility closet or outdoors as recommended by the manufacturer.
• Use non-flammable materials like masonry or metal and follow the manufacturer’s clearance recommendation or maintain a 3-foot clearance around the BESS for cooling and fire safety.
• Consider environmental hazards like flooding, extreme temperatures, snow accumulation, falling objects or vehicle impact, and keep the system away from heating equipment.
• Ensure the area is well-ventilated and check if permits are needed.

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 the manufacturer’s recommended clearance, removing any objects or debris and trimming vegetation as needed.
• Though you should keep a fire extinguisher nearby for non-battery-related fires, never use it on a BESS fire. If you notice smoke, gas or chemical odors, evacuate immediately and call 911.
• Keep inverters and all BESS equipment out of the reach of children and pets.

It’s natural to have questions about emerging technologies like BESSs. Always work with certified manufacturers and installers to ensure safety, and contact your utility early in the process to check for specific requirements for installation, the grid interconnection process and available incentives.

When installed properly, a BESS can save money, provide reliable power during emergencies, and reduce dependence on the grid.