Attorney-General Simon Corbell.

Attorney-General Simon Corbell. Photo: Katherine Griffiths

ActewAGL is to push ahead with a plan for a vast solar power farm that will cover 45 hectares on the NSW border south of Canberra.

The city's dominant electricity retailer says it still wants to build the green energy plant - which would become the capital's second large-scale solar farm - despite losing out in 2012 to build the ACT government's first plant at Royalla, south of Tuggeranong.

Spanish firm Fotowatio Renewable Ventures won the tender to build the Royalla plant, off the Monaro Highway, in a reverseauction process.

But ActewAGL has won an exemption from the ACT government from the requirement for an environmental impact report before building its huge renewable power generation operation. The plans for the Williamsdale site, just off the Monaro Highway at Angle Crossing Road, include 280,000 ''solar modules'', arrayed in 15 rows and and associated equipment, capable of generating 20 megawatts of power.

The company, partly owned by the ACT government, says land in north-western Belconnen was considered but Williamsdale was preferred because of superior ''geotechnical, heritage and land tenure considerations as well as its proximity to suitable transmission infrastructure''.

ACT Environment Minister Simon Corbell granted the exemption on January 13 under the Planning and Development Act 2007 after the company argued it had already undertaken six separate studies into the effects of the project on the natural environment in the area.

''The six supporting studies and the comments of the Conservator of Flora and Fauna provide sufficient information on the impacts of the proposal from the clearing of native vegetation,'' ActewAGL's consultants wrote in their application.

''Further investigation and environmental assessment of the impacts of the proposal on clearing of native vegetation is not required for this project.''

The exemption means the power company is free to move on to the next phase in its preparations, a development application under the ''impact track'', the category reserved for large projects.

But the territory's Conservator of Flora and Fauna described the requirement to remove 140 trees from the site as ''regrettable''.

''The 140 trees to be removed are hollow bearing and are likely to be a foraging and breeding resource of local importance,'' according to a summary of the Conservator's remarks. ''Loss of these trees is regrettable but the proponent has

offered an offset plan to address the impacts in relation to the loss of these trees.

''An offset plan should be part of the conditions of any future development approval and should include a proposal that the trees to be removed are used to rehabilitate the degraded woodlands in the vicinity.''

ActewAGL's loss to Fotowatio Renewable Ventures in September to build the capital's first large-scale solar plant was a blow to the utility and it suffered another setback last month when it lost a $16 million, two-year ACT government electricity supply contract to Queensland company ERM Power Retail in December.

But ActewAGL's general manager of business development and strategy Dianne O'Hara said the company was pushing ahead with the solar farm proposal despite missing out to the European company.

''ActewAGL has been working on a large-scale solar project with its preferred partners for some time, including undertaking relevant environmental and site-specific studies and assessments at a site in Williamsdale,'' Ms O'Hara said.

''Despite not being successful in the initial round of the ACT government's large-scale solar auction, ActewAGL remains committed to pursuing renewable energy generation.''