Greens leader Shane Rattenbury has slammed a proposal to realign Monaro Highway to cut through the centre of a solar farm, saying it is "well out of step" with the ACT government's commitment to renewable energy.
The government is considering realigning the Monaro Highway to bypass Hume's industrial precinct as one of two options for a major upgrade of the road between Isabella Drive and Canberra prison.
A realigned route would cut through the centre of the Mugga Lane solar farm and skirt the boundaries of West Jerrabomberra Nature Reserve, according to government tender documents.
It would also traverse a 129 hectare privately-owned block of land. The block's owners, Brian and Leita Barron, could not be reached for comment.
A preliminary feasibility study into the option last year found the government would have to navigate a number of "constraints" to deliver the realignment, but Roads Minister Chris Steel said it was "common sense" to explore the possibility.
Mr Rattenbury, the ACT's Climate Change Minister, said the proposal was "well out of step" with the government's vision for Canberra as a sustainable city.
Cutting a brand new solar farm in half with a freeway isn't a sensible transport optionGreens leader Shane Rattenbury
The 48,000-panel solar farm was opened in 2017, as part of an ACT government's plan to source 100 per cent of the territory's electricity needs from renewable energy by 2020. The government pays the farm's owners, Maoneng, for each megawatt hour of electricity it produces.
"It's one thing to talk the talk on Canberra as a sustainable city, " Mr Rattenbury said. "Actions from government need to match the scale of this ambition."
"Cutting a brand new solar farm in half with a freeway isn't a sensible transport option, and isn't in step with this vision."
The AECOM report was presented to the government in December, but Mr Rattenbury first learned of it after a report last week in The Canberra Times. Maoneng were also unaware of the proposal until it was contacted by the publication.
Mr Rattenbury said he was troubled by the study's finding that the new route could have a "significant impact" on a local population of grassland earless dragon, which is an endangered species.
"We need to protect the habitat of Canberra's endangered species from avoidable threats - including from motorways that could further risk their survival," he said.
The ACT and federal governments have committed $200 million to upgrade Monaro Highway.
Mr Steel last week said he expected the money would be spent on an upgrade of the existing alignment, which would include an underpass or overpass at the intersections of Isabella Drive and Lanyon Drive.
But he said it was "prudent" to assess both options at the preliminary stage.