Alion Energy solar tracker scores first deal for “difficult” solar farm locations

Renewables developer Enernet Global has officially declared its intention to use the “above ground,” low-risk solar tracking technology of Alion Energy for the 62MW solar farm it is building next to the ageing Vales Point coal plant in New South Wales.

In a joint statement, the two companies confirmed that the concrete ballasted StormTracker system would be the exclusive single-axis solar tracker solution for the much talked about Vales Point solar project.

The use of the new-to-Australia technology was broached last month, as part of the announcement of a 10-year off-take agreement between the New York based Enernet and the coal plant’s owner, Delta Electricity, for the output of the solar farm.

Alion’s technology was selected for its low maintenance design, targeting project sites where traditional pile-driven or screw-piles aren’t feasible – in this case the rehabilitated ash dam that will host the Vales Point solar farm.

The above-ground foundation works to significantly reduce the risk and associated costs of difficult project sites by removing the need to carry out detailed geotechnical and pile engineering.

It also clears the way to build solar farms on sites that, like Vales Point, are less than ideal geotechnically speaking, but are well positioned close to existing grid infrastructure and areas of network demand. And it will reduce demand for agricultural land that has at times pitted solar developers against regional communities.

Alion Energy’s regional sales director, Aidan Bone – who worked previously for what was Australia’s largest solar PV EPC contractor, RCR Tomlinson – said the technology caught his eye for its ability to minimise one of the two biggest risks involved in developing a solar farm: ground and grid connection.

Bone says there is significant cost – even on sites not considered to be “difficult” – to pre-drilling, earth works, post-driving, tracker-failure, high-risk construction activities and yield loss due to soiling in operations.

These issues, he adds, have caused all EPC’s some pain, with RCR publicly writing down $57 million on one project, as RenewEconomy reported here, mostly due to geotechnical conditions.

“When RCR went into administration, I knew I wanted to bring this technology to Australia,” he said.

“With a huge development pipeline across Australia it was important to find a low risk solution that could be constructed on any project site that a solar project developer proposes.”

As you can see in this video and in the image below, the foundation for the panels is a concrete ballasted rail, instead of a steel pile, creating a rigid A-frame structure that Alion says cuts the tracker weight in half, and thus reduce transport costs.

Further benefits include the fact that project developers only have to ship and transport half the amount of steel from steel making facilities, as the concrete for the ballast can be procured locally.

The design life of the concrete ballasts, meanwhile, is 50 years, and when the project is decommissioned they can be crushed up and re-used locally as road base.

Bone says Enernet and Alion are currently investigating the possibility of using some of the Vales Point coal ash in the cement mix for the solar farm.

The tracking technology – a variation of which is used by the vast majority of global solar farms these days, to maximise solar generation – uses a geared pivot arm which is designed to be able to withstand winds of up to nearly 170km/hour with no oscillation, while the natural frequency of the structure means it will not gallop in any wind event.

In its statement this week, Enernet said it hoped the Vales Point project would pave the way to roll out Alion’s technology on other challenging sites across Australia, including other ash dam sites, mining tailings dams and municipal landfills.

“We can construct on sites that no one else can, turning unproductive sites into profit making assets!” said Alion CEO Mark Kingsley.