Through a combination of solar and gas technology, water desalination and complementary demand management strategies, the Lady Elliot Island Eco Resort, located 80 kilometres off the Queensland coast, now runs almost entirely on renewable energy, with plans to switch to 100 percent renewables in the next five years.

Motivated by the desire to reduce greenhouse gas emissions, as well as by the significant cost savings in electricity, the Lady Elliot Island Eco Resort management set out to reduce the resort’s reliance on diesel. In 2007, extensive consultation with the Great Barrier Reef Marine Park Authority and the results of an energy audit identified that a three-phase solar hybrid system would be the solution best suited to the resort’s fluctuating load profile.

The solar-diesel hybrid power system

Tropical Energy Solutions was appointed to design the electrical and solar component for a hybrid solar power system, and worked in co-operation with Peddlethorpe Architects to design the custom, all-in-one timber structure to house the panels, electronics and batteries.

The system consists of 130 square metres of solar photovoltaic (PV) panels, battery banks with 48 cells, inverters and a new generator a third of the size of the resort’s previous units. The system has a combined capacity of 110 kilowatts (kW), and is housed in a timber-framed shed structure. The shed is positioned for maximum ventilation and shading of electronics and batteries, and is a self-supporting, ballasted structure, eliminating the need for concrete slab or ground screws.

Lady Elliot Island Eco Resort Managing Director Peter Gash says that the three-phase system is unique, as it is possibly the only one in the country, and certainly the only one operating on an island.

“The design of the shed allows for convective air flow under the solar panels, making it the coolest place on the island,” adds Mr Gash.

A multidisciplinary team of craftsmen, including carpenters, electricians and the island maintenance staff, erected the system within a few weeks in late 2008.

While the solar hybrid component of the project was commissioned in December 2008, the project was not officially launched until August 2009, when complementary measures had been developed, and a significant period of time had lapsed to identify meaningful results.

Demand management and energy efficiency

Following commissioning of the solar hybrid system in 2008, resort staff identified the need for additional load reduction and energy savings to maximise the overall effectiveness of the solar hybrid system.

Mr Gash says that one of the key lessons learnt following the completion of the solar installation was that a renewable energy project is not just about supply, but – very importantly – about demand.

“It’s a bit like the planet – you’ve got to know how it all flows together. Firstly, you need to understand the limitations of each component of the system, and secondly, you need to also understand how to bring your demand to a flat line,” he explains.

This was achieved by closely studying the resort’s unique load profile and identifying where demand could be reduced.

The resort now uses instantaneous natural gas for hot water and cooking purposes. It also treats its own sewage and produces its own water through an energy efficient, on site desalination plant.

Overall, Mr Gash says the project will be a process of continuous refinement, as those maintaining and operating the system learn how it operates as a whole. This, he says, is invaluable knowledge.

The balance sheet

“Previously we had to barge in 45,000 litres of fuel from Gladstone every three months; that’s been slashed to between 10,000 and 15,000 litres of fuel over the same period,” Mr Gash says.

With fuel savings in this order, he estimates that the project – which cost in excess of $600,000, supported by a $200,000 grant through the Federal Government’s Remote Renewable Power Generation Program – will be paid for in two years.

“Of course there are intangible costs that we have not factored in, but there are also intangible gains.”

While acknowledging that the resort’s big advantage was that the particularly high price of kilowatt hours on the island, he says the quick payback period of the project should encourage others to look at developing similar projects.

Encouraging results for a bright future

Encouraged by these outstanding results, the long term goal is to run the entire resort on solar generated power, with the diesel generator as emergency backup only.

This will be achieved by adding further solar PV panels and increasing the battery storage capacity, and of course, through the continual process of managing demand, which Mr Gash says is an ongoing process that can always be improved.

He says that other renewables could also contribute to the system in the future.

“We built the system so that we could incorporate wind or wave power if they ever become viable for us. We’re open minded and eager to listen and learn.

“Hats off to the blokes who helped us. It’s giving us better results than we ever thought.”