Power from the sun

Alice Springs Airport is the first in the southern hemisphere to have a solar power station. (Solfocus)

Emma Kelly reports on a solar power scheme from ‘Down Under.’

Alice Springs Airport is the first in the southern hemisphere to have a solar power station. (Solfocus)

Solar power and Australia are just made for each other, so it’s hardly surprising that an airport in the country has become one of the first in the world to have solar energy providing a large chunk of its power.
By mid-September, Alice Springs Airport in the Northern Territory was expecting to receive around 28% of its total power requirement from the sun following the commissioning of a 235kW solar power station using new concentrator photovoltaic (CPV) technology.  In doing so, the airport becomes the first in the southern hemisphere to have such a power station and the first airport in Australia to have a large scale – more than 100kW – photovoltaic system providing a direct source of renewable energy to its internal grid.
The power station will reduce the airport’s carbon emissions by about 470 tonnes of carbon dioxide a year – the equivalent of about 70 Alice Springs households per annum, according to Ian Kew, Chief Executive Officer of Northern Territory Airports, which owns Darwin International Airport, Alice Springs Airport and Tennant Creek Airport.
“We are a major electricity user in Alice Springs and this project seemed an ideal way to demonstrate our commitment to harnessing the benefits of renewable energy,” says Kew.
Alice Springs is no stranger to solar power – it is one of seven Solar Cities in the Australian Government’s Solar Cities Programme.  The programme is creating a new energy future for the country by trialling solar technologies with cost reflective pricing, energy efficiency measures and metering technologies.  The Alice Solar City project is designed to explore how solar power, energy-efficient technologies and new approaches to electricity supply and pricing can encourage residents and businesses to adopt sustainable energy solutions.

The installation at Alice Springs Airport, work on which started in April, comprises 28 SolFocus SF-1100CPV tracking arrays, each measuring approximately 26ft (8m) wide and 23ft (7m) high. (Solfocus)

The airport’s solar project is the second of Alice Solar City’s five planned projects, which has already seen the town’s Crowne Plaza Hotel install a large flat plate solar system that is meeting up to 80% of the hotel’s power demand during the day and is reducing its carbon dioxide emissions by 420 tonnes per year.
Alice Springs Airport, which had a passenger throughput of 680,958 in the 2009/10 financial year, is located about nine miles (15km) south of the township of Alice Springs at the heart of Central Australia.  It has previously used solar power to a limited extent.  In 2008, for example, the mains powered terminal hot water service was converted to a 400 litre solar power unit, says Don McDonald, formerly General Manager of Alice Springs Airport and now development manager (infrastructure) at Darwin International Airport.
The airport’s new solar power station is located in a field about 760 yards (700m) northwest of the terminal building and, at the size of a football field, is visible to passengers from the ground and in the air.
The A$2.3 million (US$2.1m) airport project has received A$1.132 million (US$1m) of funding from the Australian Government as part of the Alice Solar City Project.  The airport has worked with Alice Solar City for several years on the project, with support from Alice Springs-based CAT Projects, which assessed the financial and technical aspects of the technology and later conducted project management and supervising installation work.
Brisbane-based solar energy specialist Ingenero was selected by the airport in mid-2009 as principal contractor to construct the power station.  Ingenero is a development partner for California, US-based SolFocus which supplied the CPV technology for the project.  This is the first use of SolFocus’ CPV technology in the southern hemisphere.
CPV systems are an emerging solar technology that offers significant potential for cost reductions in photovoltaic systems, according to the project partners.  Traditional PV systems use a large amount of photovoltaic material, which is expensive.  SolFocus technology uses only small amounts, in conjunction with less expensive materials such as glass and steel, to capture sunlight and direct it onto a very small PV cell.  Ingenero says the: “highly efficient” triple junction photovoltaic cells used in the CPV were originally developed for satellites in space.  The cells are capable of operating at twice the efficiency of standard solar panels and at much higher temperatures.  The SolFocus technology uses panels made up of inexpensive mirrored dishes almost one foot (30cm) in diameter to concentrate the sun’s rays by 650 times.
SolFocus will use one of the 28 airport arrays for research and development to gather data and test new products in the Alice Springs climate. (Solfocus)

Due to the use of CPV tracking technology, whereby the arrays track the sun increasing the amount of energy produced, the airport’s power station is outputting more electricity than similar sized static systems.  It is rated at 235kW, with an annual output of 600MWh.
SolFocus says its technology is particularly effective in areas of high direct normal incident radiations – sunny locations – such as Alice Springs.  “CPV works best in environments with clear skies and little cloud cover so that means most of Australia other than the coastal fringe.  SolFocus is very optimistic about the future prospects for our technology in Australia and we are happy to be entering this market with Ingenero as a development partner,” says SolFocus chief technology officer and co-founder Steve Horne.
The US company says it is one of the few CPV providers in the world with commercially ready technology and expects CPV technology to be more widely available within the next five years, with projects like Alice Springs Airport paving the way for its wider adoption.
The installation at Alice Springs Airport, work on which started in April, comprises 28 SolFocus SF-1100CPV tracking arrays, each measuring approximately 26ft (8m) wide and 23ft (7m) high.  The arrays are pole-mounted and designed to capture maximum energy by tracking the path of the sun across the sky.  Ingenero says at the end of each day the arrays will close down for the night by turning its panels a few degrees off vertical to protect them from dust and other hazards.  Each individual array is rated at 8.4kW peak power, with electricity fed directly into the airport’s high voltage electricity network.  SolFocus will use one of the 28 airport arrays for research and development to gather data and test new products in the Alice Springs climate.
McDonald says the project was ahead of contract schedule, despite Alice experiencing unusually heavy rain.  “For a relatively remote location it has gone very well using predominantly local contractors for the field work, for example, foundations, erection and cabling, with most bought in components delivered in good condition,” he says.
The airport’s solar use is unlikely to stop there, with the solar power station site capable of expansion up to four times its current size.  “Our location offers a unique opportunity to become the first airport in the world to be powered 100% by solar energy and we would be thrilled if we could make this happen some time in the future,” says Kew.
Above: Alice Springs Airport is the first in Australia to have a large scale – over 100kW – photovoltaic system providing a direct source of renewable energy to its internal grid. At the end of each day its arrays close down for the night by turning their panels a few degrees off verticle to protect them from dust and other hazards. (NWTA)

“As part of the project the high voltage infrastructure – cabling, ducting, switching – has been independently future-proofed for expansion possibilities,” says McDonald.  He adds: “Expansion to 100% will depend on the success of this project and the economics.  Of course it can never really be 100% as airports operate at night as well.”  The airport group does not have plans at the moment to extend the project to Darwin International Airport or Tennant Creek Airport, McDonald adds.
In addition to the solar power station, work is ongoing to make the airport terminal more energy efficient, including energy-efficient light globes, motion sensors and timers to control lights and other electrical appliances.  Last year the airport joined the Large Business Energy Efficiency Incentive Programme run by Alice Solar City and consequently commissioned a A$110,000 (US$100,600) project to replace over 600 light fittings and install more than 60 motion sensors throughout the terminal.  This alone is expected to save around 57,000kWh, as well as A$15,000 (US$13,700) per annum, says McDonald.
The airport is also encouraging its tenants to undertake their own solar installations, with Australian National Helicopters, for example, already having installed a 5kW flat plate solar power system to produce 70% of their energy needs per annum.