Boosting the power of remote communities

Engineers Australia
May, 2007 Page: 42

A new wind-diesel powerstation is being constructed in the seaside town of Hopetoun, as its proximity to the Ravensthorpe Nickel mine has resulted in a near tripling in size of permanent housing, placing added strain on the local infrastructure. Verve Energy is building the powerstation to meet the new demands for energy.

The new station comprises seven low load Detroit Diesel 320kW engines and two 600kW Enercon wind turbines. Ken Littlewood, manager sustainable energy assets for Verve Energy, said: "The winddiesel technology is all about maximising wind penetration and minimising diesel consumption while maintaining a very high level of reliability for the town." He explained that the diesel engines can operate at a 7% load which is quite unusual for diesel generators. "Generally diesel generators want 40% loading on the machines, but we have developed some "smarts" in the control system that enable us to bring the loading right down. It helps prevent glazing of the generators;" Littlewood said.

He added that Detroit Diesels was the only top level manufacturer that would support running the engines at 7% loading, explaining that the engines offered the capability to modify the control system and fuel injection systems.

Algorithms to control the loading on the diesel generators and maximise the wind integration were developed in conjunction with Power Corporation of Northern Territory. Verve Energy now owns the intellectual property, and the company's engineers are continually working on the development of the control algorithms.

Verve Energy said it was achieving 40% to 50% of wind contribution to the Hopetoun loads on a monthly basis, and it had reported up to 98% instantaneous contribution.

Littlewood said: "We maintain supply of diesel fuel to guarantee a minimum 10 days of fuel all the time. Generally, with good wind penetration we can cut consumption by half so in Hopetoun I expect the consumption rate will be around 1500L/d when the wind is blowing." The current design represents the upper limit of population for a wind-diesel system - with about 700 houses connected to the network. Verve Energy general manager trading and sustainable energy Greg Denton said: "The engineering challenge for us is to expand the standard product and make it more useful for more opportunities.

Hopetoun will present that challenge first, where we will need technology in the future." A second new wind-diesel powerstation is also under construction at Coral Bay where the increasingly popular holiday destination of Ningaloo Reef is requiring extra capacity. Littlewood said that because it is in a cyclone area Verve Energy has sourced cyclone M rated wind turbines.

These turbines are specifically designed so that they can be lowered and tied down when a cyclone approaches. "In Coral Bay the technology is slightly different as the cyclone-rated wind turbines are less controllable, so we have a 500kW fly wheel (a power store) integrated into the system to sink excess wind energy and help control fluctuations on the system," Littlewood explained.

The 275kW wind turbines at Coral Bay are developed by Vernier. They were originally designed to be lowered for maintenance purposes but when installed in New Caledonia the design was found to be practical in times of cyclonic weather.