Using Battery Energy Storage Systems (BESS) for Reliable Backup Power
Introduction
Certain equipment, such as pumps in water utilities, require rapid power restoration, typically within a few seconds, to prevent service disruptions or damage. Traditional diesel or gas-powered generators take longer to start and supply power, leading to delays in restoring critical services.
Battery Energy Storage Systems (BESS) provide a faster, cleaner, and more efficient backup power solution. They can supply power to either permanent or temporary power supplies, bridging the gap instantly during outages by acting as the primary power source. This rapid response ensures critical loads are supported immediately, avoiding costly downtime.
How BESS Supports Critical Loads
When a power outage occurs, the BESS takes the load for a short period, allowing an alternative power source to be introduced or for the system to be safely shut down. BESS also helps maintain essential power quality parameters such as frequency and voltage regulation, which are crucial for the proper functioning of sensitive equipment. This results in a stable and resilient power system, reducing the risk of service disruptions.
Key Sectors Benefiting from BESS Backup Power
- Utilities: Pump stations in sewage and wastewater management are essential to prevent overflows and maintain sanitation.
- Construction, Services, and Contracting: Critical equipment such as lifts and safety systems need to remain operational to ensure safety and efficiency.
- Manufacturing: Continuous power is vital to avoid production interruptions.
- Petrochemicals: Reliable power is critical for safety and process control.
Benefits of Using BESS for Backup Power
- System Resilience: Instantaneous power supply during outages.
- Frequency and Voltage Regulation: Maintains power quality for sensitive loads.
- Power Factor Regulation: Improves overall electrical efficiency.
- Lower Fuel Use: For unreliable grid sites, the battery backs up the load until the generator starts, reducing fuel use by keeping the generator off most of the time leading to high fuel savings. For off-grid sites, the battery improves generator efficiency.
- Reduced Emissions: Cuts CO2 and other pollutant emissions by minimising generator use.
Real-World Examples of BESS Backup Power
Example 1: Remote Sewage Site Protection
A customer operates a sewage site in a remote location with frequent power cuts, causing control systems to trip and pumps to shut down. This leads to sewage overflow into a local river, risking pollution and fines. The site only becomes aware of outages after overflow begins.
Traditional Solution: A 200 kVA generator running 24/7, which is inefficient during low demand periods.
BESS Solution:
A BESS unit (90/120, 150/150, or 300/422 kVA) is installed so mains power passes through the BESS before supplying the pumps. While mains power is stable, it passes through normally. During an outage, the BESS inverter instantly powers the pumps, preventing overflow. A modem sends email notifications on power loss or restoration, enabling faster response.
Example 2: Construction Site Concrete Pour
A construction company requires uninterrupted power for a critical two-month concrete pour. Traditional solutions use multiple generators running in sync, increasing fuel consumption and emissions.
BESS Solution:
Integrating BESS with generators allows one generator to be turned off, reducing fuel use by up to 50%. This setup provides full power resilience while minimising environmental impact.
Example 3: Electrical Contracting Switchgear Swap
During a switchgear replacement in an office block, any power loss could cause financial penalties. Traditionally, two generators are run in load share for power backup.
BESS Solution:
Generators run in load-on-demand mode with BESS managing load efficiency. The BESS supplies power when possible, starting generators only when needed. If a generator fails, the second starts automatically. If true 1+1 is needed, the generator can run with the BESS, and if the first generator fails, the load-on-demand setup starts the second generator while the BESS maintains the load. If the BESS fails, the Automatic Mains Failure (AMF) system starts generators to maintain supply. This approach saves fuel by enabling one generator to act as standby while the BESS optimises generator efficiency.
Important Technical Considerations for BESS Backup Power
- Control System Compatibility: The customer’s control system must tolerate the brief 30ms power transfer break when switching from mains to BESS.
- Load Sizing: The load must not exceed the BESS pass-through capacity.
- Backup Duration: Define how long the BESS should support the load during outages.
- Integration with Generators: BESS can be combined with generators for hybrid solutions that optimise fuel use and emissions.
Conclusion
Battery Energy Storage Systems provide a fast, reliable, and environmentally friendly backup power solution for critical loads across multiple sectors. By ensuring immediate power restoration, maintaining power quality, and reducing fuel consumption and emissions, BESS enhances operational resilience and supports sustainability goals.
For more detailed insights and case studies on battery storage solutions, please visit Aggreko’s resource page.