Stationary battery energy storage - Stationary batteries at substations can provide both backup and ancillary services, improving asset utilization.

Stationary Battery Energy Storage (SBES) refers to battery systems that are fixed in a specific location, designed to store electrical energy from the grid or a local generation source, and then discharge that energy back into the grid or a load at a later time. The term is primarily used to distinguish these systems from mobile energy storage, such as batteries used in electric vehicles.

Scale and Primary Functions
SBES systems are categorized by their scale and application:

Front-of-the-Meter (FTM) / Utility-Scale: Large, multi-megawatt systems sited at substations or power plants. This is the focus of the substation battery market.

Behind-the-Meter (BTM) / Commercial & Industrial (C&I): Systems installed on a customer's property (e.g., factories, office buildings) to manage their local consumption.

Residential: Smaller systems installed in homes, often paired with rooftop solar panels.

The versatility of SBES allows it to provide numerous critical services, transforming electricity from a commodity that must be consumed instantly to one that can be managed and scheduled:

Arbitrage: Charging the battery during off-peak, low-cost periods and discharging during peak, high-cost periods to generate revenue.

Ancillary Services: Providing fast-response services like frequency regulation and voltage support to maintain grid health.

Peak Shaving: Reducing the maximum demand a customer or utility pulls from the grid, lowering monthly utility bills (BTM) or deferring infrastructure upgrades (FTM).

Renewable Energy Integration: Storing variable wind and solar energy for later, scheduled use.

Technology Landscape
While various technologies are used for SBES, including flywheels and compressed air energy storage (CAES), batteries, particularly lithium-ion, dominate the modern, high-growth market segment.

Lithium-ion (Li-ion): The leading technology, favored for its high energy density, high efficiency (round-trip efficiency often over 85%), declining costs, and long cycle life. LFP (Lithium Iron Phosphate) is the preferred Li-ion chemistry for stationary utility applications due to its superior safety profile and durability.

Lead-Acid: Maintains a niche role, mainly in backup power for substations and in certain legacy BTM installations where low initial cost is prioritized over cycle life.

Flow Batteries: An emerging technology that stores energy in external electrolyte tanks. They offer advantages for very long-duration storage (8+ hours) because their power and energy ratings can be scaled independently, making them a future competitor to pumped storage hydropower.

Economic and Regulatory Impact
The growth of SBES is intrinsically linked to energy market design and technological maturation. Favorable regulatory frameworks, such as the FERC orders allowing storage to participate in wholesale markets, have established a clear financial pathway for SBES deployment.

The declining Levelized Cost of Storage (LCOS) for Li-ion systems makes SBES an increasingly economically compelling alternative to traditional power generation sources (like natural gas peaker plants) and T&D infrastructure upgrades. For utilities, deploying SBES at a congested substation can be faster and cheaper than building a new power line or transformer bank—a concept known as Non-Wire Alternatives (NWAs).

In summary, stationary battery energy storage is the core technology enabling the modern, flexible grid. Its deployment at the substation level (FTM) is crucial for managing the bulk power system and supporting the reliability of renewable energy integration across the U.S.

Stationary Battery Energy Storage

Q1: What is stationary battery energy storage?
Battery systems that provide fixed backup and energy support in substations.

Q2: How do they benefit the grid?
They enhance reliability and store surplus renewable energy.

Q3: What technologies are common?
Lead-acid and lithium-ion dominate installations.