The latest outlook for Western Australia's gas users spells trouble for a market traditionally immune to the supply and price woes afflicting the east coast.
As the federal government mulls a national gas reservation policy, WA's approach of setting aside some production for local use was found to be a "cornerstone" of the state's supply to local users.
Yet the WA domestic gas market faces a "tight" supply-demand balance between 2023 and 2029, with demand up to 5 per cent higher than potential supply, according to the 10-year outlook.
The Australian Energy Market Operator has warned that renewables are projected to only partly replace shuttered coal plants and gas generation is forecast to be required for baseload power and system security.
Demand is expected to exceed potential supply from 2023 to 2026, but supply gets back into the black from 2027 to 2029 when Woodside Energy's Scarborough project is expected to come online.
The domestic gas market then moves into a larger deficit from 2030 onwards as coal generation is shut down, and from a decline in production from existing gas fields.
"The strong linkages between WA's gas and electricity sectors mean that changes occurring in one sector will have an impact on the other," AEMO executive Kate Ryan said.
Developing new gas fields could fill the gap, as well as drawing from WA's existing gas storage which can deliver up to 210 terajoules per day.
Large gas users transitioning more rapidly to lower-emissions energy sources could also ease expected supply gaps, the report said.
Demand for gas generation in the South West Integrated System, the state's main electricity network that serves most of the population, is expected to grow from 127TJ per day in 2023 to 304 TJ per day in 2032 as the end of coal-fired power drives up demand.
State-owned energy corporation Synergy announced in June that coal power stations would be retired by 2030, with the amount of rooftop solar coming online in the state roughly equivalent to adding a new coal-fired plant every year.
An estimated $3.8 billion is planned to be invested by the state government in new green power infrastructure, including wind generation and big batteries, to ensure stability and keep a lid on costs for consumers.
But AEMO's modelling shows renewables won't fully compensate for the loss of coal-fired power.
The deficit is expected despite a sharp increase in decarbonisation plans across the mining sector in the past year as higher costs bite.
In iron ore mining, gas demand is forecast to decrease, with gas usage is expected to drop from 157 TJ per day in 2023 to 107 TJ per day by 2032, despite rising production.
AEMO continues to exclude hydrogen from the gas demand forecast, with most at an early planning stage and focused on transport or export.
The gas-intensive $6.5 billion Perdaman urea project, which could be delayed by the collapse of construction firm Clough, was not included in the forecasts.
