Lessons From Operating a BESS for the First Time

Why Storage Matters (Again)

As solar deployments surge worldwide, simply “charge by day, discharge by night” is no longer enough. Inverter limits, grid codes, revenue targets, warranty clauses, safety margins, and long-term degradation all demand a more sophisticated approach to BESS operation.

That’s where data analytics for BESS come in, so operators can turn mountains of data into action rather than noise.

In a joint webinar, Laura Perez Amigo, Operations Manager at InterEnergy and Vijandran Naidoo, Director Energy Storage and Grid Integration at Brookfield Renewable walked through their lessons from operating a BESS for the first time. Here is a summary of what they learned.  

Project Snapshot: FV3 in Punta Cana

InterEnergy is operating a 40 MWh Li-ion BESS co-located with a 20 MW AC solar farm—by far the largest storage installation in Central America and the Caribbean. The site is part of an independent medium-grid/ Single Electricity Market that supplies 65 percent of the Dominican Republic’s hotel district. Its primary objectives are to drastically reduce diesel generator run-time, stabilize PV output, and uphold strict frequency and voltage requirements. Key system modes include static versus dynamic PV firming, energy shifting for evening peaks, fast frequency response, and grid-support functions such as virtual synchronous machine operation and black-start capability.

How Analytics Make BESS Operation More Profitable

Four analytical modules proved indispensable to InterEnergy:

1. Digital Commissioning

Automated capacity reference and dynamic stress tests at various states of charge generated a digital commissioning report that went far beyond traditional checks. The report highlighted cell-voltage spreads, temperature imbalances, and DC-resistance anomalies - down to the rack level. With this information, InterEnergy’s BESS manufacturer could swap out a faulty module before it affected BESS performance.

2. Performance Management

Operating a 40 MWh system can produce billions of data points each day. No human can comb through raw logs fast enough.

The solution is a hierarchical diagnostic workflow: first up are system‑level alarms. These are followed by alarms on the container, rack and individual string level. “Stoplight” dashboards visually flag which components are underperforming, enabling InterEnergy to address revenue‑draining imbalances or preempt potential warranty claims before they escalate.

3. System Monitoring

Outages happen. In this project, data from the site was collected at a 30-second resolution, with an on-site RTAC device transmitting the data directly to an SFTP server. When a disruption in data ingestion occurred, TWAICE’s real-time alert system quickly detected the issue. As a result, data was temporarily logged only locally at a reduced 5-minute resolution. Investigations traced the root cause to a network configuration problem at the site.

4. Warranty Tracker

By automatically mapping actual vs. expected metrics (e.g. availability %, equivalent full cycles, State of Health) InterEnergy gets daily timeseries charts with green/red flags and can model stepwise or straight-line degradation warranties. Now, the operator walks into annual capacity test reviews armed with hard data.

Key Challenges & Lessons Learned

InterEnergy’s early BESS deployment in Punta Cana surfaced critical technical and operational challenges -each offering valuable lessons for future projects.

1. Precision Is Key: A lack of technical precision in the early SEM grid code, coupled with multiple Huawei firmware revisions, resulted in extended SCADA–PPC testing.  
   Early engineering drawings omitted DC combiner boxes and temperature sensors, while an incomplete Bill of Materials (BOM) caused commissioning delays. Now, exhaustive BOM reviews are mandatory to avoid surprises.

2. O&M Procedures Are Changing: Dispatchers moved from diesel generators to managing PV + storage. Static PV firming (fixed set‑point) was easier to adopt—but dynamic firming (tracking irradiance curves) yields better performance.

3. Ambiguity Will Lead to Disputes: Ambiguous warranty and performance clauses in initial contracts led to interpretive disputes. InterEnergy now incorporates clause‑by‑clause performance definitions for its future BESS contracts.

4. Data Is Power: A 200 MWh site can generate 18 billion data points per day; by 2030 that balloons to 400 trillion. Analytics turns chaos into cash.

5. Revenue Assurance: Imbalance = lost kilowatt-hours. Knowing exactly which rack or string is underperforming protects your bottom line.

6. Warranties Won’t Wait: Continuously tracking state of health, cycle counts, and availability ensures no surprises during annual capacity tests or warranty audits.

For any operator moving beyond simple charge/discharge cycles, these insights - and the analytics capabilities that deliver them - are essential for safe, compliant, and economically optimized energy storage operations. Watch the full webinar here!

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Want to see how BESS analytics improves operation? Watch our product tour!