Hybrid Power
The Client: Joule Energy
The Background
In early 2017, EPSA was engaged by Joule Energy in their partnership with Northern Adelaide Waste Management Authority (NAWMA) on an innovative first-of-its-kind project to combine solar and methane gas in an energy production farm. EPSA provided an EPC solution for the 1.15MW(ac) PV solar plant providing engineering, design, construction and commissioning.
The Requirement
The PV solar modules are arranged into 46 mini power blocks each feeding a dedicated 25kW (SMA) inverter – the strings are then split into three separate arrays, with AC output from each collected to supply the EPSA-supplied HV transformer kiosk. The kiosk transforms the voltage to 11,000V AC for supply to the grid via the client-operated power station.
Control of the plant is achieved using an optical fibre network that controls each inverter via an EPSA-developed control system, which relays the information back and forth to each of the 46 inverters. The controller features a web-connected online portal to provide the client with up-to-date information on the solar plant status including current plant output, daily yield and alarms.
The Solution
A key feature of the solar plant control is the dynamic reactive power control – since this solar plant is exporting to the grid, the grid voltage is affected with higher export values. To counter the ever growing problem of grid voltage stability, the solar plant is able to dynamically change the output power factor to import or export 100 per cent of the plant’s output in reactive power in a trade-off for active power. This means that the plant can help stabilise the local grid voltage throughout the day.
The Results
11,040 Cat® PV solar modules are mounted on fixed tilt steel frames that contour challenging terrain.
The collective electricity generated from both the landfill gas and solar sources is expected to be over 11,000 megawatt hours of renewable energy per annum – enough to power more than 1,900 homes 24/7.
The solar plant has been successfully exporting green energy into the South Australian grid since it was commissioned in late October 2017 – Cat®’s first solar plant on Australian soil.
