NSW abandons plans to remotely cap aircon capacity in the heat, but SA pushes on

Plans to ease pressure on the state’s electricity grid by remotely cutting power to air conditioners on hot days have been called into question, but SA might still push on.

Plans to ease pressure on the state’s energy grid by cutting power to airconditioners on hot days have been called into question after fresh research has put a dampener on the controversial plan.

Since July 2023, most new aircon systems supplied in SA have been required to have a “demand response capability”.

A presentation to installers ahead of that change said aircons would need to be able to communicate with a “remote agent” via Wi-Fi or mobile network.

Alternatively, they could “have a physical interface designed to connect to an external demand response enabling device”.

The reform was the first major step towards Big Brother-style control of cooling via signals that trigger three modes – one that turns off the compressor, another reducing capacity to 50 per cent and a third that limits it to 75 per cent.

The next step towards achieving “demand flexibility at scale” is an 18-month trial – expected to begin later this year – involving hundreds of volunteer households.

Demand response schemes have the potential to save all consumers money by avoiding or delaying construction of an expensive new network that is funded by increasing bills.

However, the state was warned as far back as 2021 that the extent of power reductions via cutting aircons’ capacity can be “overstated”.

There are questions over the merits of remotely capping aircons’ capacity. Picture: Supplied

The alarm was raised in a submission from energy market expert Martin Gill to a SA government consultation paper.

In his submission, Dr Gill, who supports demand response as a concept, cited two trials, including one by the CSIRO, which showed that even when it was 35C outside, an aircon cooling a thermally inefficient room was able to operate below 50 per cent capacity most of the time. So when a signal was sent to halve the aircon’s capacity, the demand reduction was negligible.

NSW recently pulled back from adopting a similar approach to SA, saying it was “unviable” for its peak demand reduction scheme (PDRS) for reasons including “the low certainty of energy reduction”.

Martin Gill brought the CSIRO case study to light in a submission to the SA government. Picture: Richard Dobson

“The standard outlines communication by reducing compressor power input to a percentage of the rated input power,” NSW authorities said.

“A CSIRO case study has shown that because most airconditioners run at a partial load, even on very hot days, and that the true energy reduction … is far lower than expected.”

Dr Gill, who until recently was the Consumers Federation of Australia on several Standards Australia working groups, said a better option was to slightly increase the set temperature to a level that was still comfortable.

A government spokesman said “the capability requirement established in SA is not currently associated with a local policy comparable to the NSW PDRS”.