Hermannsburg, Yuendumu & Lajamanu Power Stations

Mini-grid connected, solar concentrator hybrid generation
Location: NT

The sites

Three remote communities in Central Australia, Hermannsburg, Lajamanu and Yuendumu, were identified as appropriate for solar power stations. Each is an indigenous community of several hundred households. The solar dish concentrator technology enables significant reduction in diesel consumption for power generation in the communities.

Technology

Solar dish power stations are installed at the three locations; each of the 30 dishes is equipped with 24 per cent efficient silicon-based PV cells. Each solar dish has 112 curved reflecting mirrors mounted on a steel frame, which tracks the sun throughout the day. The mirrored dishes concentrate sunlight by 500 times onto PV modules housed within a receiver. The tracking mechanism allows electricity to be produced whenever the sun is more than 5° above the horizon.

Five hundred times sun concentration is energy-intense enough to melt steel, therefore the PV cells in the solar receiver are mounted in a way that allows efficient dissipation of thermal energy as well as extraction of electricity. A closed-loop cooling system across each plant enables the PV cells to operate at optimum temperatures and rejects heat into adjacent sewerage ponds. This arrangement provides additional evaporation from the ponds to reduce the need for overflow pumping.

The plant control system incorporates a battery bank which smoothes the output profile from the power station to the mini-grid. This protects the diesel generators from sudden changes in load, giving the generators time to react when a cloud passes in front of the sun. Sensors located at the receiver enable real-time monitoring and sun-tracking optimisation. The proprietary control system design enables remote operation with periodic attendance by service staff.

The PV modules installed in the solar dish receivers consist of silicon-based PV cells supplied by US company SunPower. One solar dish at Hermannsburg has been upgraded with a receiver incorporating the latest multi-junction PV cell technology. These cells were developed by Solar Systems in conjunction with US company Spectrolab, a subsidiary of Boeing. The upgrade of the dish at Hermannsburg increased its DC output from approximately 24 kW to 35 kW, i.e. by around 50 per cent. This solar dish is the world’s
most efficient solar power generator.

The power output of the latest solar dishes is over 1,500 times greater per PV area than
standard flat plate solar panels. This is because they operate at 500 times sun concentration
and three times more efficient PV technology.

Energy purchase and supply

The project is producing electricity under a long-term power purchase agreement with Power and Water Corporation, the local electricity supplier. The three plants are expected to produce 1,555,000 kWh of electricity per annum and are accredited under the MRET scheme. Electricity is converted to grid-quality alternating current and exported to the local electricity mini-grids, providing up to about 50 per cent of the grid load and offsetting the requirement for the existing diesel generators.

Environmental impact

The power stations are expected to save 420,000 litres of diesel and 1,550 tonnes of greenhouse gas emissions each year.

Other distinguishing features of the project

The solar dish is upgradeable, enabling it to take advantage of future advances in PV technology. PV cell efficiency is continually improving: the world laboratory record is currently 40.7 per cent cell efficiency. The solar dish receiver containing the PV modules can be replaced with a higher efficiency receiver in about an hour meaning that the original investment can be enhanced rather than made obsolete by technology
improvement, in contrast to flat plate technology where the whole installation must be replaced.

Success of the project to date

The solar power stations were designed to provide around 30 per cent of the daytime electrical requirements of the communities. In practice, when the communities’ requirement is low the power stations have provided up to 50 per cent of the daytime load. The project has received a prestigious award for engineering excellence in the 2005 Engineers Australia Excellence Awards.

Solar Systems is genuinely committed to maintaining excellent working relationships with local communities and has demonstrated corporate leadership by involved and respectful consultation and participation in Central Australian communities powered by its solar dish technology.

Funding arrangements and acknowledgements

The combined project cost of $7 million was offset by a $3.4 million grant from the Australian and Northern Territory Governments under their Renewable Remote Power Generation Program.

“These projects showcase some of the best work of the Australian solar power industry and what can be done when governments, the community and the private sector work together. Solar power provides a competitive, secure energy source and will contribute to the economic prosperity of these communities in the future.”
Clare Martin, Chief Minister of the Northern Territory