A plan to reduce the carbon footprint of the Canberra space station is facing an obstacle, with a mature-aged tree located right where CSIRO want solar panels.
CSIRO has proposed a solar array at the Canberra Deep Space Communication Complex, with a 1.7 hectare footprint on predominantly cleared land in Tidbinbilla Nature Reserve.
The project would include 37 rows of solar units, each about three metres in height, around 20 kilometres south-west of the city.
A mature-aged eucalyptus, an apply box, alongside some regenerating saplings, would need to be cleared for it to go ahead.
The tree, which impact assessments have identified as important, sits among 1.7 hectares of derived native grassland, comprised of both native and introduced species.
The space station, established in 1965 and operated under an agreement between Australia and the United States, is home to four large antennas that track deep-space robotic missions.
The project would provide an additional power source for the site and assist in powering the antennas, facilities and operational equipment.
A development application has been submitted by the Australian Department of Agriculture, Water and the Environment, stating the project is unlikely to have direct or indirect impacts on threatened ecological communities or threatened species' habitats.
However, grassland vegetation which may have some impact on the golden sun moth will be impacted, the report also states.
The golden sun moth is an endangered species, listed as threatened in the ACT.
"Given the small area of potential habitat to be disturbed and the additional habitat available in the study area and locality, the project would be unlikely to have a significant impact on this species," the report says.
Keeping the tree in place would involve the loss of 10 rows of 22 solar panels equal to 130 kilowatts and shading on an additional eight rows of 22, equalling another 104 kilowatts, plus redesign costs.
CSIRO says a contractor has advised they are unlikely to recover the lost capacity by moving the project elsewhere on the property, due to steep gradients to the south and west, plus an antenna exclusion zone to the east.
"By reducing the size of the array to allow for the tree, as well as the subsequent shading caused by the tree, the energy produced by the system will reduce by an estimated 14.1 per cent," the application says.
"It is currently estimated that the PPA [Power Purchase Agreement] contractor will increase the currently agreed tariff rate by 12.8 per cent to cover this loss.
"It is currently estimated that the project will lose around $710,000 in savings over the 15 year term of the PPA if the tree is required to be protected."
The ACT government has recently moved to prevent further loss of mature-aged trees in the ACT, after a decline of more than 6 per cent between 2015-2020.
A recruitment call went out to local green thumbs last month, part of an effort to help ACT reach its 30 per cent urban tree canopy cover target by 2045.
A CSIRO spokeswoman said the application was currently being considered by the Department of Environment.
"Pending the outcome, we will work with relevant stakeholders to ensure any vegetation of heritage significance identified is protected in accordance with the Environment Protection and Biodiversity Conservation Act," the spokeswoman said.
