Under the ACT government's plan to ditch fossil fuels by 2045, Canberra homes and businesses will not be able to install a gas connection next year.
As natural gas prices convince them to switch to electricity to save money, households are leading the way.
Canberra's new suburbs have already been designed without gas connections.
The government introduced legislation today to end all connections to new builds - including in older suburbs - as of January 1.
Andrew Barr, Chief Minister, said the transition would be gradual and gentle, ahead of the rest of the country's schedule. He said cutting off new gas connections would be the only way to meet the ACT's goal of eliminating greenhouse gas emissions.
The days of cheap gas in Australia seem to be over, Mr Barr said.
About two-thirds of Canberra homes use natural gas - for heating, water systems or cooking - and fuel accounts for about 20 per cent of the ACT's emissions.
The ACT already buys more electricity from renewable sources than it uses: it reached its 100 per cent target three years ago.
The government announced last month plans to phase out petrol and diesel engines, because most of the emissions come from transport.
Barr said that the government would help Canberrans turn off their gas by 2045.
He said that we need to make this transition in a responsible and considered manner that provides certainty to households and businesses, but also supports them during the transition.
Even before the Ukraine war worsened the global energy crisis, prices had caused Canberrans to disconnect from mains gas.
After accounting for inflation, gas costs for ACT households doubled in the two decades to 2020.
They are expected to rise a further 19 per cent over the next decade - about $220 a year more for a typical home.
Electricity prices are predicted to fall 3 per cent.
Around 2 per cent of Canberra households have been cutting off their gas supply because of these pressures and environmental concerns.
The government expects that to increase to 2.5 per cent a year.
Its modelling shows that market forces alone would reduce Canberra's gas use by almost 60 per cent by the year 2045, without any policy interventions.
People and businesses will be helped by a range of incentives, according to the government.
These include existing interest-free household loans of up to $15,000 to improve energy efficiency or switch to electricity.
The subsidies for low-value homes are up to $5,000.
Climate Change Minister Shane Rattenbury said that disconnecting from mains gas was a long-term goal, and there was no need to hurry, though it made sense to avoid annual connection fees.
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A recent government survey found that cost was the biggest barrier preventing Canberrans from switching to electricity.
The cost of removing a gas meter and supply pipes is about $800 per household.
The Australian Energy Regulator said the government would work with the Australian Energy Regulator to reduce or abolish that charge.
Rattenbury said the ACT gas network would be shut off in 2045, but the government wouldn't stop people from buying gas in LPG tanks if they wanted to.