Bernam made the remarks to the Australian Domestic Gas Outlook conference this morning to call for more investment to boost supply and keep prices low.
ExxonMobil and BHP, through their joint venture in the Bass Strait, is the biggest supplier of gas to the domestic market on the east coast.
Last week the two committed to a A$400 million spend to get 200PJ of gas from existing fields to market, starting from next year.
Victoria has the highest gas demand and largest infrastructure network in the country, which is primarily used for residential and commercial heating.
However the Victorian government is targeting a 25% reduction in gas demand by 2025, and 50% by 2030, across multiple scenarios as part of its plans to reduce overall emissions by 50% by 2030, and reaching net-zero by 2050 to prevent runaway climate change.
This is despite approving a lift on a long term onshore conventional gas moratorium last year, with plaudits from the Labor government.
"This legislation and the opening again of conventional gas exploration is something that should be seen as part of a very progressive policy on energy in Victoria,' Labor's Brownwyn Halfpenny said in 2020 when it was first repealed.
The Domestic Gas Outlook finished its public consultation process in August and is expected to be published during the current quarter.
However, Bernam used his speech to attack the outlook saying it was a "significant risk to the gas investments that will be needed in the state and is the single largest threat to near term gas supply for the 80% of Victorian households that rely on gas for heating, hot water and cooking".
"We will carefully evaluate whether to proceed with or discontinue those additional investments considering any policy decision related to the Victorian Gas Substitution Roadmap," he said.
Last year the independent body Infrastructure Victoria released an interim report providing advice on how to best transition the state's gas network to achieve its climate goals.
It recommended reducing overall gas demand, by investing in energy efficiency measures and electrification in residential and commercial sectors, to help create gas reserve supplies for critical industrial purposes such as chemicals manufacturing as well as gas-powered generation to firm up renewables.
It warned against expanding existing gas networks to new residential and commercial developments, saying it could potentially lock-in future emissions and could create underused or stranded assets.
Bernam argued in his speech however that additional gas supply into the domestic market was essential to maintaining energy security as coal-fired power stations start retiring.
"To keep market prices down and ensure supply over the next several years to the millions of homes and businesses that rely on gas, more investment is required," he said.
Bernam said its 200PJ gas development, announced last week, was more competitive and would provide more gas than either Santos' 70PJ Narrabri project or the developments in Beetaloo "and it will be produced in the next few years, when it is most needed".
Victorian energy minister Lily D'Ambrosio said the government was considering "gradual transition pathways" and that it would not penalise those who wished to continue using gas.
"Gas is no longer the cheap fuel it once was - to help address this we're assisting Victorians to shift to cheaper clean energy alternatives as we transition to net zero emissions by 2050," she said.
In an op-ed in the Nine Newspapers this afternoon, Environment Victoria CEO Jono La Nauze described ExxonMobil as a "bully" that was taking aim at the government for "daring to think about supporting Victorian households with the ballooning cost of gas heating and hot water, including helping fund the sue of electrical appliances as an alternative".
"The inconvenient truth for ExxonMobil is that not only is their product making people and our planet sick, Victorians are quickly realising it's also burning a hole in our wallets," he said.
"To heat our homes and hot water, electricity is now cheaper than gas, and as coal is replaced in the grid with Victoria's abundant solar and wind resources, it's also cleaner."
The Australian Energy Regulator in its submission to Victoria's roadmap warned however there was a risk that switching from gas to electricity too early would put pressure on both gas and electricity prices, noting that significant new investment in electricity networks would be needed to support the uptake.
"Further, the pace of the transfer of gas demand to electricity creates reliability risk for the electricity network if not carefully managed," the AER said.
It also noted however that the future use of gas, and gas distribution networks, will depend on the commercial viability of zero-emission gas such renewable hydrogen and biogas.
Bernam emphasised in his speech that Exxon's operations in Gippsland had reduced flaring by 44% and the use of gas as fuel by 24%, saying the next opportunity would be in CCS.
"Australia has the opportunity to become a global leader in CCS with favourable geology backed by growing policy support and an established regulatory framework that is more developed than other countries in our region," he said.
Nauze argued that Exxon should be working with the Victorian government to help transition its workforce in line with the energy transition "rather than leading Victorians on with false promises of a fossil fuel powered future".
"Make no mistake - the only loser from the clean energy transition under way is the oil and gas industry's financial bottom line."
