Struggles

Papua New Guinea (PNG) faces significant challenges in providing reliable and accessible public electricity due to its outdated and insufficient electricity infrastructure. Rural areas, in particular, often lack access to electricity altogether.

This school, like many others across PNG, encountered serious obstacles on its pursuit for quality education. Frequent power outages disrupted daily activities, hindered teaching sessions, and compromised essential facilities such as lighting and computing equipment. Moreover, the school's dependence on diesel generators resulted in huge operational expenses, draining financial resources that could have been allocated to academic improvements and infrastructure development.

TBB Solution

When one door closes, another opens. In consideration of the school’s consistent sunlight throughout the year, combined with its load capacity, backup time requirement and its energy demand for a constant power supply both day and night, a carefully designed 30kW solar mini-grid system was installed, perfectly addressing the school’s electricity challenges. This mini-grid system was set up in AC+DC coupling configuration, comprising the following components:

• Inverter Chargers: 6 x 5kW TBB Kinergier Pro, configured in a robust 3-phase
• MPPT Solar Charge Controllers: 2 x 250V/120A TBB Solar Mate, designed for charging 48V battery banks from PV arrays, facilitating efficient DC coupling
• PV Inverter: 1 x 30kW PV inverter seamlessly integrated with the output of the Kinergier Pro for AC coupling. Its output power is regulated by Kinergier Pro via frequency shift technology to avoid batteries being overchagred
• Lithium Batteries: 12 x 48V/5.04kWh TBB ES100, housed in 4 IP65 battery cabinets
• PV Panels: 40kWp
• Wireless Data Logger: TBB Kinergy WiFi sends real-time system data to NOVA Web & APP - the TBB free-to-use online monitoring platform
• System Monitoring: NOVA Online Portal allows authorised users to monitor and manage the system from anywhere in the world
• Backup Diesel Generator: The starting and stopping of the generator is automatically controlled by Kinergier Pro based on preset conditions such as battery SoC, load power and time period settings.

System Working Mode

Since the installation, a 24/7 power supply is guaranteed by the mini-grid system with minimum fuel consumption. To ensure system work at its optimum capability, TBB customized the working mode for this case. Solar-battery-generator works in turns, maximizing solar self-consumption and reducing fuel consumption.

The system operates as follows:

1. When solar power exceeds the school load demand, it supplies power to the loads and charges the batteries with any excess energy.
2. If solar intensity decreases and solar power is insufficient to meet the load demand, the system prioritizes using solar energy and supplements with battery power.
3. In the absence of solar power, the battery supplies power to the loads until reaching a preset low SoC. At this point, Kinergier Pro initiates the starting of the generator, which will take over powering the loads. This prevent battery over-discharge, which could shorten battery lifespan.
4. During consecutive rainy days, the battery SoC may stay low. Kinergier Pro will start the generator to power loads and recharge the batteries.

System Performance

The Kinergier Pro's transformer-based design and high overload power rating (2x) ensure reliable power delivery, capable of meeting the demands of school’s heavy-duty loads. The system's scalability, supporting parallel and three-phase operation up to 9 Kinergier Pro units, lays the foundation for future expansion to accommodate the school's evolving energy needs.

Furthermore, Kinergier Pro’s AGS functionality minimizes generator runtime and enhances operational efficiency. As the brain of system, Kinergier Pro controls the on and off operation of the generator according to user-defined conditions. Equipped with power assist and power control functions, Kinergier Pro can boost the output of the generator with power taken from the batteries in case of short-time peak power demand, and recharge the batteries with the spare power when the load demand reduces.

The school’s solar system is connected to TBB NOVA monitoring platform, which enables real-time monitoring, remote management, data analysis and troubleshooting through a computer or a mobile app.

System Turnout

Since its commissioning, the system has been operating smoothly, ensuring a constant power supply. The school now enjoys stable, clean and cost-saving electricity uninterruptedly, providing better conditions for the teachers and students. The school administration is highly satisfied with the system, praising TBB for its reliable solutions, excellent products, and comprehensive services.

Mission: Easy Power, Easy Life

By providing dependable and sustainable power solutions like this mini-grid system, TBB continues its unwavering mission to bring an Easy Power, Easy Life to homes, communities and businesses worldwide, paving the way for a brighter, greener future.