The solar array is to be built directly across the road from the Uriarra village, upsetting local residents, who want it pushed back on the block, out of their immediate line of site.

With a decision expected this month, Mr Corbell said the government was at "an important point" in negotiations with the developer.

"I'm not in a position to make further announcements about that at this time but I am seeing positive steps to resolve the concerns that residents have at Uriarra," he said.

Pushed further, he said, "The developer has indicated to the government that they are willing to revisit the issues of concern to the residents. We welcome that and are looking forward to seeing the outcome."

Solar farm developer Ashleigh Antflick, of Elementus Energy, said he was working hard for "an outcome that will be satisfactory for everybody".

Once he had development approval, the array could be operational in six to nine months, he said. He had not sought compensation or a contribution from the government for any change in location or change to the project, he said.

The glimmer of hope for Uriarra residents who have fought a long campaign against the solar farm came as Mr Corbell released a report on the ACT's progress towards its ambitious target of reducing greenhouse gas emissions by 40 per cent on 1990 levels by 2020.

Mr Corbell said the ACT was on target to achieve the reduction in greenhouse gases, along with its target of sourcing 90 per cent of the city's electricity needs by 2020.

However, the report from Commissioner for Sustainability and the Environment Robert Neil found that the government doesn't have the information to answer the central question: How are we tracking against sector greenhouse gas emissions targets?

The problem is two-fold: the national greenhouse gas inventory has a two-year time lag, so the most recent data is from 2011-12; and the ACT's plans to reduce emissions cover different sectors than counted in the inventory. The inventory looks at emissions in energy, industry, agriculture, land use, forestry and waste. The ACT is working to reduce emissions in household energy use, business energy use, transport, waste and energy supply.

Mr Neil has recommended the ACT adopts its own system of accounting for greenhouse gas emissions in line with overseas standards, and uses them to track progress year by year so it can know whether the 40 per cent target has been reached in 2020.

He said the ACT was among the most progressive jurisdictions in the world on climate change.

The ACT government has funded three large-scale solar farms, including Uriarra, under 20-year deals, and has recently chosen three wind farms, which will between them supply a third of the city's electricity needs. He is also planning a waste-to-energy plant at the Mugga Lane landfill and a next-generation solar farm. The balance of the 90 per cent renewable target is expected to be met with another large-scale wind auction.

Mr Corbell said with the Royalla solar farm already operating, construction of the Mugga Lane solar farm was expected to begin this month.

He was "very confident" the ambitious clean-energy targets would be met. While the data lagged two years behind, the government was able to accurately measure the abatements delivered from its policies, so it knew it was on target, he said.

"We have already demonstrated with the award of 200 megawatts of wind energy generation that we can supply over 30 per cent of our total electricity needs as a city just from that process. That, combined with large-scale solar and the rooftop solar that's already installed or due to be installed in the ACT, is giving us 40 per cent of our electricity needs by 2017. So to be at 40 per cent by the year 2017 shows that 90 per cent by 2020 is very achievable," he said.