Retrofitting energy management systems in remote environments is often challenged by a lack of infrastructure, unreliable communications, and difficult terrain.

For the Tonga Water Board (TWB), these factors were especially noticeable across Tongatapu, where a complex groundwater pumping system supports the water supply for Nuku’alofa. Using LoRaWAN wireless technology in combination with the Tridium Niagara platform, Direct Control enabled smart water and energy management across this distributed, off-grid network, delivering real-time visibility, remote control, and operational optimisation.

The challenge in Tonga

Nuku’alofa, Tonga’s capital and largest town, depends entirely on groundwater sourced from a fragile karst aquifer. This fresh water layer floats above seawater and is pumped via ~50 distributed borehole pumps. Each pump station, typically a small standalone shed, feeds into one of eight reservoirs that in turn supply the town. Previously, all operational control was manual: pump start/stop sequences, reservoir checks, and distribution monitoring were labour-intensive and reactive.

The recently commissioned 400 kW solar plant with battery storage presented an additional opportunity, if TWB could synchronise water production with solar generation, significant energy cost savings could be realised. But without centralised control, visibility, or automated coordination between pumps, reservoir levels, and solar generation, TWB couldn’t fully utilise this asset.

The key requirements were:

●  Automate pump control based on water levels and system demand
●  Monitor volume and pressure across the network
●  Synchronise pumping activity with solar generation
●  Enable real-time system visibility and alarm notifications
●  Achieve this across a large, dispersed area with minimal physical infrastructure

Energy management solution

Direct Control engineered and deployed a comprehensive solution built on three core components: LoRaWAN wireless communication, field-deployed sensors and controllers, and a Tridium Niagara-based central management platform.

LoRaWAN for remote connectivity

LoRaWAN offered the perfect fit for connecting remote, power-limited sites without relying on trenching cable or cellular infrastructure. With support from Digicel, a dedicated LoRaWAN network was established to cover the pump field and urban zones, with a secure radio backhaul connecting all devices to the main control system.

Smart monitoring & control

●  Custom-designed pump control panels integrated LoRaWAN-enabled devices for run status, fault signals, and remote      control.
●  Pulse-counting units were deployed on water meters to measure flow volumes.
●  Pressure sensors were installed at strategic points within the network to monitor distribution efficiency and detect anomalies.
●  Reservoirs were fitted with 4–20 mA analog pressure sensors, interfaced via Delta field controllers using BACnet for seamless integration and reliable level monitoring.

Unified control via Tridium Niagara

To bring together diverse field data and manage it holistically, Direct Control built a centralised monitoring and control platform using the Tridium Niagara Framework

●  Niagara enabled integration of BACnet (for Delta controllers), ModbusTCP (for the solar farm), and LoRaWAN inputs.
●  Custom Niagara drivers were developed to locally manage LoRaWAN device communication.
●  Operators gained access to a unified interface displaying real-time water production metrics, pump status, reservoir levels, and solar performance, including battery charge and system output.

Results & impact

Operational intelligence & automation

TWB operators now receive real-time data on system performance and can automate pump sequences based on reservoir levels, significantly reducing manual intervention. Remote start/stop functionality and fault alerts improve operational responsiveness.

Sustainability through visibility

By tracking bore production, pump activity, and distribution flows, TWB can now compare bore efficiency, plan maintenance proactively, and protect the long-term viability of the freshwater resource.

Solar performance unlocked

The solar plant, previously a “black box,” is now fully integrated into the control platform. Battery storage status and power output are visible to operators in real time, and pump activity can be aligned with solar availability to maximise renewable energy usage and reduce electricity costs.

This project demonstrates the power of integrated energy and water management in remote, infrastructure-poor environments. By combining wireless telemetry (LoRaWAN), intelligent control (Tridium Niagara), and energy-aware automation, TWB has transitioned from manual operations to a modern, data-driven utility capable of protecting its water resource while maximising solar investment returns.

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