Project Case Study
Indonesia 550kW Off-Grid Solar + Energy Storage System
Complete solar PV + battery storage + power distribution solution for a remote timber factory in Indonesia
Many industrial operations in remote Indonesian islands face limited or no grid access. Reliance on diesel generators results in high operational costs (LCOE of 0.35–0.45 USD/kWh), fuel logistics challenges, and unreliable power quality that affects sensitive production equipment.
Real project site photos from the Indonesia off-grid timber factory power system deployment.
Timber factory production workshop — hardwood beams and processing machinery
Wood processing area — outdoor timber yard with sawn lumber
Timber processing warehouse with industrial machinery
Outdoor sawmill workshop — band saw stations
Overview of the hybrid solar + battery + diesel backup power distribution system.
Integrated power generation, energy storage, and distribution architecture for remote industrial applications.
High Safety
Multi-layer protection with FM-200 fire suppression system
Liquid Cooling
Temperature-controlled battery racks, ≥91% system efficiency
Smart EMS Control
Integrated BMS + PCS control with remote monitoring
Remote Monitoring
Real-time SOC/SOH, alerts and cloud dashboard access
Diesel Backup
500kVA generator with ATS automatic seamless transition
832V LFP BESS
6 × 261kWh racks, 1566kWh total, BCMU + 4× BMU
| Parameter | Specification |
|---|---|
| PV Capacity | 550kWp monocrystalline silicon PV array |
| Battery Storage | 1566kWh LiFePO₄ (261kWh × 6 racks), 832V system |
| Hybrid Inverter | 550kW PCS with integrated MPPT, islanding protection |
| Distribution Transformer | 800kVA oil-immersed, 20kV / 0.4kV |
| LV Main Breaker | 1000A ACB, 0.4kV main distribution panel |
| Diesel Generator | 500kVA standby with ATS auto-transfer |
| Battery Cooling | Liquid cooling temperature control, ≥91% efficiency |
| Fire Suppression | FM-200 gas suppression system for battery room |
| Load — Saw Machines | 250A MCCB feeder |
| Load — Conveyor Systems | 250A MCCB feeder |
| Load — Wood Processing | 200A MCCB feeder |
| Load — Workshop & Lighting | 160A + 100A MCCB feeders |
| Energy Strategy | Potential diesel savings depend on site-specific load profile and solar conditions |
| System Voltage | 0.4kV |
| Grid Type | Off-grid Hybrid |
| Backup Source | Diesel Generator |
| Battery Chemistry | LFP (LiFePO₄) |
| Protection Level | IP54 |
| Operating Mode | 24/7 Continuous |
System Design & Single-Line Diagram
Complete electrical single-line diagram (SLD) covering PV array → DC combiner → inverter → LV switchgear → distribution panels → loads. Battery charge/discharge paths and diesel backup integration point clearly indicated.
Load Analysis & Sizing
Detailed 24-hour load profile analysis identifying peak demand (420kW), average load (280kW), and night-time baseline (180kW). PV array and battery sized to meet factory energy requirements based on measured load data.
Battery System Integration
Battery rack layout design with thermal modeling. BMS communication architecture integrating with inverter control system. Charge/discharge strategy optimized for battery longevity and system efficiency.
Protection Coordination
Selective protection coordination study: DC side (fuses, surge arresters), AC side (MCCBs, ACBs), and battery side (DC breakers, fuses). Arc flash hazard analysis for LV switchgear.
Power Distribution Engineering
LV switchgear busbar sizing, cable sizing with voltage drop calculations (< 3% from source to load), short-circuit level verification, earthing system design, and cable tray routing.
Installation & Commissioning Support
Detailed installation drawings, cable schedules, termination diagrams, and commissioning checklists. Remote commissioning support via video call with on-site technicians.
Site Survey
On-site assessment of factory layout, load equipment, solar irradiation, and existing diesel infrastructure.
Week 1–2Load Analysis
24-hour load profiling: peak 420kW, average 280kW, night baseline 180kW. Sized PV and BESS accordingly.
Week 2–3Electrical Design
Complete SLD, protection coordination study, cable sizing, earthing design, and equipment layout drawings.
Week 3–5Equipment Selection
Specified 550kWp PV, 832V/1566kWh BESS, 550kW PCS, 800kVA transformer, LV switchgear with MCCB feeders.
Week 4–6Factory Integration
BESS racks, PCS, switchgear, and EMS pre-assembled and tested at factory before shipment to site.
Week 6–8Installation
PV array ground-mount structure, equipment positioning, cable routing, terminations — all on-site at remote location.
Week 8–12Testing & Commissioning
Insulation resistance, polarity, functional tests. Solar+battery+diesel mode transitions verified. Protection relay settings commissioned.
Week 12–14System Operation
Handover to factory operations team. EMS dashboard training. Remote monitoring enabled. Continuous operation commenced.
Final stageMeasured electrical loads at the timber processing factory — basis for PV array, BESS, and distribution equipment sizing.
| Equipment | HP | kW | Current | Daily Consumption |
|---|---|---|---|---|
| Saw Machines | 180 | 134 | 250A | 1,608 kWh |
| Conveyor Systems | 160 | 119 | 250A | 1,428 kWh |
| Wood Processing | 120 | 90 | 200A | 1,080 kWh |
| Workshop Auxiliary | 90 | 67 | 160A | 804 kWh |
| Lighting & Other | 60 | 45 | 100A | 540 kWh |
| TOTAL | 610 | 455 | 960A | 5,460 kWh |
Remote island factory with no grid access, fully dependent on diesel generation
No Grid Access
The factory is located on a remote Indonesian island with zero utility grid connection. All electricity was being generated by on-site diesel generators running 24/7, resulting in very high operational costs and significant carbon emissions.
Diesel Cost & Logistics
Diesel fuel had to be transported by boat and truck, adding 15–20% logistics premium on top of fuel cost. Generator maintenance (oil changes, filter replacements, major overhauls) occurred every 250–500 operating hours, causing planned downtime.
Unstable Power Quality
Diesel generators produced voltage fluctuations of ±8% and frequency variations of ±2Hz under load changes — well outside the tolerance range of sensitive production equipment, leading to product quality issues and electronic component failures.
24/7 Operation Requirement
The factory operates three shifts continuously. Any unplanned power interruption results in production loss, material waste, and schedule delays. Diesel generator reliability was declining with age.
Environmental Compliance
Increasing local environmental regulations and corporate sustainability goals required a significant reduction in diesel consumption and carbon emissions.
Integrated solar PV + battery storage system with complete power distribution
Photovoltaic Generation System
- ▸550kWp monocrystalline silicon PV modules with high-efficiency cells (21.5% module efficiency)
- ▸Ground-mount fixed-tilt structure optimized for tropical latitude (5°S)
- ▸DC combiner boxes with string-level monitoring and surge protection
- ▸DC cabling with UV-resistant insulation rated for tropical outdoor exposure
Battery Energy Storage System (BESS)
- ▸1.2MWh LiFePO4 battery bank, 51.2V nominal system voltage
- ▸Rack-mounted battery modules with integrated Battery Management System (BMS)
- ▸Cell-level monitoring: voltage, temperature, state of charge (SOC), state of health (SOH)
- ▸Thermal management system maintaining battery temperature at 20–35°C for optimal cycle life
- ▸Long-cycle battery design at 80% DoD for extended operational life
- ▸Fire suppression system and smoke detection for battery room safety
Power Conversion System (PCS)
- ▸500kW off-grid hybrid inverter with integrated MPPT solar charge controllers
- ▸Bi-directional AC/DC conversion for battery charging/discharging
- ▸Seamless mode transition: solar-only, solar+battery, battery-only, diesel-backup
- ▸Advanced power management: peak shaving, load following, generator auto-start/stop
- ▸Grid-forming capability providing stable 400V/50Hz reference voltage and frequency
LV Power Distribution
- ▸GCS-series withdrawable LV switchgear: 400V, 1250A main busbar, 65kA breaking capacity
- ▸AC distribution board with MCCBs for production line, lighting, HVAC, and auxiliary loads
- ▸Automatic Transfer Switch (ATS) for diesel generator backup integration
- ▸Power quality monitoring: voltage, current, power factor, harmonics, energy metering
- ▸Earthing system: TN-S configuration with earth grid < 1 Ohm resistance
Backup Power & Transformer
- ▸XLPE insulated power cables per IEC 60502, total 3,200m including DC and AC runs
- ▸Cable trays, conduits, and containment system with IP65 rating for outdoor sections
- ▸Lightning protection system with air terminals, down conductors, and surge protective devices
- ▸Equipment shelter: prefabricated container housing for BESS, inverter, and switchgear
Decision Factors
Expected Benefits
Battery Liquid Cooling
832V LFP battery racks with active liquid cooling temperature control. Maintains 20–35°C optimal range for maximum cycle life. System efficiency ≥91% at rated power.
ATS Diesel Backup
500kVA diesel generator with Automatic Transfer Switch for seamless transition during extended low-solar or battery-depleted periods. EMS-controlled auto start/stop logic.
IEC Protection Coordination
Full selective protection coordination per IEC 60364 and IEC 61439. DC side: fuses + SPD. AC side: MCCB + ACB with adjustable trip curves. FM-200 fire suppression for BESS.
LV Distribution Integration
0.4kV main distribution panel with 1000A ACB incomer. Six MCCB feeders with smart metering: Saw 250A, Conveyor 250A, Wood 200A, Workshop 160A, Lighting 100A, Auxiliary 160A.
Remote Monitoring & EMS
Integrated EMS with BMS+PCS communication. Real-time SOC/SOH tracking, load forecasting, fault diagnostics, and cloud dashboard accessible via 4G from anywhere.
Modular BESS Design
6 independent 261kWh battery racks with individual BCMU+BMU management. Additional racks can be added without system redesign. Spare MCCB slots for future load expansion.
Automated EMS decision logic for solar + battery + diesel hybrid operation across daily cycles.
Daytime Operation
06:00 – 18:00
Power Flow: PV → Loads + Battery Charge
Night Operation
18:00 – 06:00
Power Flow: Battery → PCS → LV Bus → Loads
Backup / Emergency
On-Demand Trigger
Power Flow: Diesel Gen → ATS → LV Bus → Loads + Battery Charge
Mode Transitions:All switching between solar, battery, and diesel is managed automatically by the EMS. Transition time: <30 seconds. No manual intervention required. Remote mode override available via cloud dashboard.
This project demonstrates the capability of integrating solar generation, battery energy storage, transformers, low-voltage distribution systems, and industrial protection devices into a complete off-grid power solution for remote manufacturing environments.
The system was designed for continuous operation in tropical outdoor conditions with unstable infrastructure access, emphasizing reliability, energy efficiency, and maintainability.
Oil-Immersed Distribution Transformer
S22-MS22-M 800kVA, 20kV/0.4kV
Main distribution transformer — 800kVA step-down for factory LV supply
View Series →LV Main Distribution Panel
GCS1000A ACB, 0.4kV, with MCCB feeders
Main LV switchboard with ACB incomer and distribution to sawmill/processing loads
View Series →Solar PV Modules (supplied through partners)
Solar550Wp monocrystalline, 550kWp array
Primary energy generation — 550kWp total array capacity
BESS Racks (supplied through partners)
BESS832V, 261kWh × 6, LiFePO₄, liquid cooling
1566kWh total storage with BCMU+BMU management and FM-200 fire suppression
Hybrid PCS (supplied through partners)
Inverter550kW hybrid inverter, MPPT + islanding
Bi-directional power conversion, battery charge/discharge, EMS integration
Diesel Generator (supplied through partners)
Diesel500kVA standby, ATS auto-transfer
Emergency backup power with automatic start/stop via EMS control
View Series →Q: What is the typical payback period for an off-grid solar + battery system?
Payback period depends on local diesel costs, solar irradiance, and system utilization. For remote sites with high diesel transport costs, energy savings can be substantial. A site-specific financial analysis based on actual load profile and fuel prices is recommended for each project.
Q: Can the system operate during cloudy or rainy days?
Yes. The 1566kWh battery provides extended autonomy for night-time baseline loads. During extended cloudy or rainy periods, the diesel generator automatically starts as backup via the ATS. Actual solar fraction depends on seasonal weather patterns and load profile at the site.
Q: What maintenance does the system require?
Solar PV modules require periodic cleaning (monthly in dusty environments, quarterly otherwise). Batteries need annual capacity testing and terminal torque checks. Switchgear requires annual thermal imaging inspection and protection relay testing. Overall maintenance is significantly lower than diesel generators, which require oil/filter changes every 250–500 hours.
Q: Is this system scalable for future expansion?
Yes. The design includes spare capacity in the LV switchgear with reserved breaker slots, and the BESS uses a modular rack architecture — additional 261kWh battery racks can be added to increase total storage capacity using the same BMS and DC bus architecture.
Q: What certifications do the electrical components carry?
Transformers: IEC 60076; LV switchgear: IEC 61439-2; Power cables: IEC 60502; PV modules: IEC 61215 / IEC 61730; Inverters: IEC 62109; Batteries: IEC 62619 / UN38.3. All certification documents provided with equipment delivery.
Q: Can you supply a similar system for other countries?
Yes. We design and supply solar + storage systems for off-grid and weak-grid applications across Southeast Asia, Africa, the Middle East, and island nations. Each system is customized for local solar conditions, load profile, grid requirements, and logistics.
Planning an Off-Grid or Solar + Storage Project?
Tell us your location, load profile, and energy goals — our engineers will design a customized system with complete electrical BoS, pricing, and delivery schedule.