Evoenergy isn't planning to connect new suburbs to the gas network after the ACT government scrapped the requirement earlier this year.
But the energy provider will continue to plan for the roll out of "renewable gas" - such as hydrogen and bio-methane - as it highlights the potential costs of relying solely on green electricity to power the territory in the coming decades.
Evoenergy - which distributes gas and electricity in the ACT - has published a draft five-year plan for its gas network.
The plan assumes that new suburbs won't be connected to the network, and forecasts that overall gas usage will gradually decline in the coming years.
The move advanced one of the key elements of the government's climate change strategy; the phasing out of natural gas usage as part of efforts to achieve net zero emissions in the ACT by 2045.
The government's plan canvassed interim targets for weaning the territory off natural gas, including having 60,000 existing households taken off the network by 2025. However, no targets have been set in stone at this stage.
Evoengery's draft plan said there were three "pathways" to achieving net zero emissions; powering the ACT entirely with green electricity, transitioning to "renewable gas" supply, or adopting a "hybrid" model which included a mix of the two energy sources.
The report noted that gas provided about 40 per cent of Canberra's total energy needs, and delivered as much as 60 per cent in winter. Switching all customers to electricity would significantly increase demand on the network, which would consequently need to be upgraded.
"That would come at a high cost to consumers. In addition, this pathway would leave a large proportion of Evoenergy's existing gas network investment unrecovered," the report said.
The other option would be to gradually replace the supply of natural gas with forms of "renewable gas", such as hydrogen and bio-methane.
The draft plan, which was published last week for customer feedback, said it was not yet clear which was the best approach.
But it said it would be "premature" for the government to set timeframes for removing existing gas pipes, and connections, as that same infrastructure would be needed if "renewable gas" was deemed the best option to achieve the zero emissions target.
Evoenergy has been experimenting with hydrogen gas in its existing pipes since early last year.
The company's gas network's manager, Bruce Hansen, said testing so far at its Fyshwick site had shown that buried pipes were "compatible" with hydrogen gas.
Mr Hansen said the company was confident that hydrogen gas could contribute about 10 per cent of overall supply by 2030. As a distributor of both gas and electricity, he said Evoenergy was well placed to understand the territory's energy needs in the coming decades.
As part of planning for the strategy, the energy provider convened a "citizens' jury", which was torn on the pros and cons of expanding the gas network to new suburbs.
An Evoenergy spokeswoman said the company acknowledged that halting the expansion of the network would deprive new suburbs of access to a "renewable gas" supply once it became available.
"However until we have a clear transition pathway, our focus is on keeping the gas network price stable, and taking a conservative approach to investment in any new gas network," the spokeswoman said.
Minister for Climate Change and Sustainability Shane Rattenbury said Evoenergy's proposal was proof the push to phase out natural gas was "gaining momentum".
"The fact is, natural gas is a polluting fossil fuel and we must eventually phase it out to reduce emissions and tackle climate change. Approximately 22 per cent of the ACT's total greenhouse gas emissions come from natural gas," Mr Rattenbury said.
The Conservation Council welcomed plans to stop the expansion of the network to new suburbs, but said Evoenergy should go further and cease connecting new multi-unit developments to gas.
"As Canberra's density increases, building new multi-unit developments that rely on gas is irresponsible, particularly given the policy direction of the ACT Government, and risks locking unit dwellers into using polluting fossil fuel well into the future," the council's ACT region executive director, Helen Oakley, said.
Evoenergy will submit its final plan to the Australian Energy Regulator for approval in June.