Sizing a BESS for an Industrial Site
Battery energy storage systems (BESS) are transforming energy management on industrial sites. How do you size the capacity, power and protections of a BESS in Morocco?
Why an Industrial BESS?
A Battery Energy Storage System (BESS) solves several problems at once on an industrial site: peak shaving, power factor correction, backup energy reserve in case of an ONEE outage, and optimal integration of solar PV production.
In Morocco, ONEE's MV tariff structure includes a penalizing subscribed power component. A well-sized BESS can reduce this component by 20 to 35%, generating a return on investment within 4 to 7 years.
Step 1: Load Curve Analysis
The starting point is analyzing at least 12 months of MV metering data. From it we extract:
- Peak power (kW) and when it occurs.
- Peak duration (minutes to hours).
- Daily energy consumption (kWh) and its seasonal variation.
- Available PV production profile (if solar coupling is involved).
Step 2: Choosing the Battery Technology
For industrial applications, LFP (Lithium Iron Phosphate) technology is today's reference:
- Safety: stable chemistry, minimal thermal risk compared to NMC.
- Longevity: 4,000 to 6,000 cycles at 80% DoD (Depth of Discharge).
- Temperature: operating range suited to the Moroccan climate.
Step 3: Power / Energy Sizing
Two parameters define a BESS:
- Rated power (kW): determined by the peak power to be shaved.
- Capacity (kWh): determined by the required discharge duration. For 2 hours of peak shaving at 500 kW, 1,000 kWh of gross capacity is needed.
A 20% derating factor (DoD limited to 80%) and a 10% aging factor are applied, bringing installed capacity to 1,390 kWh.
Step 4: Electrical Architecture
The BESS connects to the grid via a Power Conversion System (PCS) — a bidirectional DC/AC inverter — that converts between the batteries' DC voltage and the AC grid. Essential protections include a DC circuit breaker, cell protection fuses, and a BMS with overcurrent and over-temperature cutoff.
Step 5: EMS System
The Energy Management System (EMS) orchestrates BESS charging and discharging according to defined priorities: PV production, site consumption, ONEE subscribed power threshold. ERPT programs these EMS on Schneider or Siemens industrial controllers with a dedicated SCADA interface.
Completed Example: Tafingoult Microgrid
As part of the post-earthquake Al Haouz project, ERPT designed and built a standalone 160 kWp + 600 kWh LFP BESS microgrid in Tafingoult, in partnership with Huawei and ONEE. The system was commissioned in 27 days, autonomously powering a village of 300 households.
Our engineers are available to review your project.