On Wednesday, the Supreme Court is due to rule on whether the state's environmental regulator acted lawfully in altering the licences of three coal-fired power stations.
Conservation group Environment Victoria has alleged Victoria's Environmental Protection Authority failed to consider state climate law in its licence reviews.
The matter is the first to test Victoria's Climate Change Act, introduced in 2017, and to challenge the regulation of air pollution from coal-fired power stations.
Environment Victoria has alleged the authority ignored the act by failing to impose limits or constraints on the owners of the Yallourn, Loy Yang A and Loy Yang B power stations when amending their licences following a March 2021 review.
Lawyers for AGL Energy, Alinta Energy and EnergyAustralia, owners of the three power stations, appeared in court as respondents.
The three power stations combined supply around three-quarters of Victoria's energy and account for roughly 40 per cent of the state's carbon dioxide emissions.
Environmental Justice Australia, whose lawyers are representing Environment Victoria, says the case could lead to stronger pollution limits on power stations and reduce the health burden coal-burning power stations have on communities.
Lawyers for EnergyAustralia argued the watchdog was not compelled to consider environmental principles when it granted the licences and that quashing the regulator's decision could lead to worse pollution.