Brown coal power plants believe they are ready for the long weekend's high temperatures, as energy authorities prepare for a grid stretched to the limit.
A heatwave forecast to hit Victoria, South Australia and Tasmania on the weekend has sparked an Australian Energy Market Operator warning that the system will be under pressure.
Similar heat last week, coupled with a number of brown coal-fired power station failures, saw energy prices in Victoria spike to $12,931 a megawatt hour.
Alinta Energy, which recently acquired the Loy Yang B brown coal-fired power station, is positive on its performance ahead of the warmer weather noting it was designed to run ''in extreme conditions".
"Both units are currently operating and are expected to be fully available during the upcoming weekend hot spell and into the summer period," an Alinta spokeswoman told Fairfax Media.
"While we can't speak for other asset owners, it's worth noting that Loy Yang B is well maintained and performs above international benchmark standards.
Loy Yang B tripped last week but the spokeswoman said the outages ''were not heat related'' but ''related to an uncommon system fault''.
A spokeswoman for Energy Australia, which operates the Yallourn brown coal-fired power station, said the company was focussed on keeping the plant running at peak capacity when needed.
"We're proud of Yallourn's record - on the 10 days when demand was at its highest over summer 2016/17, the plant had 92 per cent availability," an Energy Australia spokeswoman said.
"From time to time, things can go wrong with any large, complicated industrial machinery, especially ones operating in extreme conditions."
AGL's executive general manager for group operations Doug Jackson said Loy Yang A's workforce has been carrying out work to prevent further unexpected failures.
"We undertook work leading up to summer and we have carried out some last minute maintenance to ensure we are well-positioned for the weekend," Mr Jackson told Fairfax Media.
"Across our portfolio, only one unit is offline. That is a unit at Liddell and is due to come back into service at the end of the month."
Meanwhile AEMO has prepared for a system once more under strain, earlier this week issuing a warning that forecast temperatures for both South Australia and Victoria could reach the point where the grid struggles to operate effectively.
Victoria has a capacity temperature of 41 degrees Celsius and South Australia 43 degrees Celsius, putting the system at risk.
The situation is compounded by a rare heatwave affecting Tasmania, with Saturday to hit 33 degrees and Sunday to reach 36 degrees Celsius.
"Temperatures across the southeast will begin to rise on Thursday and Friday, with the hottest conditions through South Australia and northern Victoria," BOM meteorologist Sarah Fitton said.
This combination of hot days across the southern end of the National Electricity Market means states which rely on each other for power support will each be facing high demand and a strained grid as they struggle to satisfy consumption in their own state and export any additional energy.
Last week, AEMO instituted a Lack of Reserve (LOR) Level 2, which signals a tightening of electricity supply reserves and is used to encourage the market to generate more, and triggered the Reliability and Emergency Reserve Trader (RERT) mechanism, which is an agreement with large energy users - such as smelters or large manufacturers - to reduce their energy consumption or to generate power themselves, helping to secure around 1,150 megawatts of strategic reserves to return to the grid.
It is unknown whether AEMO will trigger either of these mechanisms ahead of the weekend.
"We have no current LOR conditions, however, we are continuing to monitor conditions closely," an AEMO spokesman said, adding that "this can change due to a number of factors".
Australian Energy Council general manager for policy Ben Skinner said demand is typically highest on hot weekdays and when business and industrial operations are running at full capacity.
"The biggest risk is when there is very high demand," Mr Skinner said.
"Usually that is at the end of a run of two or more hot days. Buildings are already hot, there may be low output from wind generation and solar PV output declines late in the afternoon."
Despite this, Mr Skinner was mostly positive on the grid's reliability, and backups in place, and believing it will operate through the weekend with no major failures.
"There can be localised issues with power supply on hot days, but these do not reflect systemic problems," he said.
"Although there are challenges, hydro, gas and coal-fired plants have performed during previous heatwave events and that will continue to be the case."