A stand-alone power system using renewable energy and hydrogen technologies is being tested at Kahua Ranch on the Big Island of Hawaii. Based on the infrastructure of an older power system coupling a photovoltaic array (PV), wind turbine (WT), batteries and diesel generator, the hydrogen system eliminates the use of fossil fuel. The hydrogen storage system is used for storing renewable energy.

The Kahua Ranch installation has two renewable primary energy sources: 10 kW ASE PV array and an 8kW Bergey WT. There are two ways to store energy: 1) into a battery system, made of 96 Trojan batteries of 1,785 Ah and 2) into hydrogen gas as the system includes a 0.2 Nm³/h Proton Exchange Membrane (PEM) electrolyzer from Electric Hydrogen, a 5 kW PEM fuel cell Uninterrupted Power System (UPS) from Plug Power, a 5.4 Nm³ gas storage system, and 100 liter water tank. The end user of this test bench is an 8 kW resistive load bank to simulate a wide range of load profiles.

Coupling near-commercial technologies on a 48VDC bus configuration, the main tasks of the Hawaii Natural Energy Institute, a research unit of the University of Hawaii, were the selection of the components available for this application and the development of the interface between all components allowing safe and stand-alone operation of the overall installation. This interface connects all components electrically and mechanically. It includes sensors, valves and relays connected to the Data Acquisition and Control System (DACS) for system control and data recording. A safety analysis in the design process resulted in the development of a fail-safe system. As the main components have their own controller to run safely and automatically, our DACS controls overall system shut down procedures in case of emergency such as fire, earthquake or instrumentation failure. It also optimizes the energy management in the system. In addition, it has been designed to be visible and controllable from everywhere over internet.

This article focuses on the description of the power system, its development and installation on the Big Island. Main components, developed interfaces, and recorded data are presented. The control of the installation is described using data from one day of operation. The first experimental results allow preliminary conclusions on system design and operation. Finally, the perspectives describe the wide range of information expected from this installation.