Battery Energy Storage: How It Works and Why It’s Important

In the shift toward a more sustainable and resilient energy system, battery energy storage is becoming crucial. This technology allows electrical energy generated at one time to be stored and used later. This seemingly simple capability is transformative, especially as we transition from fossil fuels to renewable energy sources like wind and solar, which are inherently intermittent. Battery energy storage captures renewable energy when it’s available and dispatches it when needed most, enhancing the efficiency, reliability, and sustainability of the electricity grid. This article explains how battery energy storage works and why it’s important.

How Battery Energy Storage Works

At its core, a battery stores electrical energy as chemical energy, which can be converted back to electricity on demand. During charging, electrical energy is transformed into chemical energy, and during discharging, the process is reversed. Battery energy storage systems (BESS) manage this process with sophisticated control systems to provide power when it’s needed or most cost-effective. Key components of a BESS include:

• Battery system
• Power conversion system (inverter)
• Battery management system
• Environmental controls
• Controller
• Safety equipment (e.g., fire suppression, sensors, alarms)

The Importance of Battery Energy Storage

Battery storage plays a vital role in our energy mix for several reasons:

Enabling Renewable Energy

Renewable energy sources like wind and solar are intermittent, producing energy only when the wind blows or the sun shines. The times of energy production do not always align with periods of high demand. A BESS stores energy when production is high and releases it when demand is high, allowing a larger proportion of energy to come from renewable sources.

Grid Resiliency and Reliability

As we shift to renewable energy, our electrical grid must handle increased variability and decentralization. A BESS stabilizes the grid by absorbing excess power during high production and releasing it during high demand, reducing blackouts and ensuring a consistent power supply. This is particularly crucial during extreme weather events.

Reducing Emissions from Peaker Plants

Peaker plants, which operate only during high electricity demand, typically run on fossil fuels and emit more greenhouse gases. A BESS can reduce reliance on these plants by storing energy during low demand and supplying it during peak demand.

Supporting Electrification

Achieving a zero-emissions future requires the electrification of industries currently powered by fossil fuels, such as transportation and heating. This transition increases electricity demand and strains the grid. A BESS helps manage increased demand and smooths out consumption, integrating electric loads without significantly expanding power generation capacity.

Energy Independence

On a localized level, a BESS allows homes and businesses with solar panels to store excess energy for later use, increasing energy independence and reducing reliance on the grid. This also reduces emissions associated with energy production and transmission.

The Benefits of Battery Energy Storage Systems

BESS offer several benefits that make them increasingly important in our energy landscape:

• Grid Stabilization: Quickly absorbs or releases power to balance supply and demand and maintain grid stability.
• Renewable Energy Integration: Stores excess renewable energy and releases it when needed, mitigating the intermittent nature of sources like wind and solar.
• Peak Shaving: Reduces electricity demand during peak periods by storing energy during low-demand periods and releasing it during high-demand periods, cutting costs and reducing reliance on peaker plants.
• Energy Arbitrage: Stores energy when prices are low and dispatches it when prices are high, creating financial savings or generating revenue.
• Backup Power: Provides backup power during outages, increasing energy resilience and reliability.
• Grid Independence and Self-Consumption: Enhances energy self-sufficiency for homes and businesses with renewable energy generation.
• Support for EV Charging: Ensures rapid EV charging without straining the grid by storing electricity during off-peak hours and dispensing it during peak usage.

Types of Battery Energy Storage

Various battery technologies are used in energy storage systems:

• Lithium-Ion Batteries: Popular due to high energy density, efficiency, and long cycle life. Chemistries include LFP (Lithium Iron Phosphate) and NMC (Lithium Nickel Manganese Cobalt Oxide).
• Lead Acid Batteries: Mature, reliable, and inexpensive, but with lower energy density and shorter lifespan under deep cycling use.
• Lead Carbon Batteries: Enhanced lead acid batteries with improved cycle life and performance.
• Flow Batteries: Use liquid electrolytes, offering long lifespan and scalability but with higher complexity and cost.
• Sodium-Sulfur (NaS) Batteries: High-temperature batteries suitable for large-scale applications.
• Solid-State Batteries: Emerging technology with potential for higher energy density, improved safety, and longer lifespans, but still in early development stages.

Commercial, Residential, and Utility-Scale Battery Energy Storage

Battery energy storage systems vary across residential, commercial, and utility scales:

• Residential: Typically ranges from 5 to 15 kWh, paired with rooftop solar installations for peak usage offset or backup power.
• Commercial: Ranges from 30 kWh to 2000 kWh, used in businesses and commercial buildings to reduce energy costs and provide backup power.
• Utility-Scale: Large systems storing many megawatts for grid applications, providing services like frequency regulation and load leveling.

Conclusion

Battery energy storage is essential for enabling renewable energy, enhancing grid reliability, reducing emissions, and supporting electrification to achieve Net-Zero goals. As more industries transition to electrification and the need for electricity grows, the demand for battery energy storage will only increase.