Vanuatu Solar Pilot, Espiritu Santo

Three sites were chosen in the Sanma district on the island of Espiritu Santo to demonstrate the efficacy of grid-connected solar PV systems by the Government of Vanuatu and the Asian Development Bank (ADB). MPower and its local partner Energy4All designed and implemented the solar systems below.

Greenstage provided three PicoGrid units to both monitor and control 4 SMA Tripower STP-10000 inverters. The PicoGrid units collect information from the SMA inverters as well as control the inverters output, using an SMA Power Control Module that slots into each inverter (see diagram below). In the case of the Hospital, there were two inverters in parallel, which presented no problem. PV modules chosen by MPower were CNPV 250W, complete with IEC 61215, 51730 certificates as well as salt-mist protection IEC 61701. Ironridge framing was used to secure the modules flush to the roof.

In order to make sure that the 3G connection is up, the PicoGrid units actively monitor the connection to the internet, and physically power down and power up the 3G modems if necessary. The 3G modems used come with an optional CRC9 external antenna port, which we outfitted with a 3dB booster antenna for better signal strength.

PicoGrid units still collect data from the SMA inverters whether or not they are connected to the internet. It caches that data and when internet connectivity returns, will shuttle that info up to the server based in Wellington, where it is visualized on the Console. All communication involved is secured using either 128-bit SSL certificates or X.509 encryption in conjunction with a Certificate Authority acting as a non-partisan independent 3rd-party authorization authority. This means that any commands issued by VUI administrators are vetted and guaranteed with non-repudiation by the system.

VUI administrators have access to a branded Console which shows the live status and generation performance of the inverters. As well, VUI administrators can securely turn off the inverters using the same console. Unlike other solutions where either monitoring or control is available only by the web server on the monitoring device, the Greenstage platform is highly customizable and extremely responsive as an HTML5 application utilizing secure web services. This means mobile platforms such as smart phones and/or tablets can be easily integrated into the full solution.

Site Generating Capacity Inverters
Sanma District Council Building 10kW SMA TriPower 10kW
Sanma Hospital 20kW 2 X SMA TriPower 10kW
College 10kW SMA TriPower 10kW

System Specifications: Hospital

  • 2 x SMA TriPower inverters
  • 20kW Monocrystalline PV Modules
  • 1 x PicoGrid Monitoring and Control
  • System Specifications: Sanma Province Council Building

  • 1 x SMA TriPower inverters
  • 10kW Monocrystalline PV Modules
  • 1 x PicoGrid Monitoring and Control
  • System Specifications: College

  • 1 x SMA TriPower inverters
  • 10kW Monocrystalline PV Modules
  • 1 x PicoGrid Monitoring and Control