By The Guardian (World News) | Created at 2024-10-18 14:10:16 | Updated at 2024-10-18 16:28:46
2 hours ago
Ever wondered why your trusty toaster abruptly failed or your widescreen TV suddenly went on the fritz, far too early in the life of the appliance?
Excessively high voltage levels might be to blame for their premature demise, energy experts say.
The costs of jamming extra volts down the power lines outside your home also extend beyond the purchase price of new appliances. Think bigger electricity bills, a grid unnecessarily strained, extra carbon emissions and underperforming solar panels.
For a century, Australian standards dictated voltage – the pressure of the electricity coursing through our wires – was set at 240 volts, within a plus-or-minus 6% band. From 2000, it was lowered to 230V (+10%/-6%) to bring us in line with most nations.
The trouble is, our voltage has typically remained close to the old standard and often above it. About 95% of readings within the national electricity market (Nem) exceeded 230V, according to research commissioned from the University of New South Wales by the now defunct Energy Security Board (ESB) in 2020.
“Maximum voltages recorded are generally towards the upper end of acceptable voltage in all states and distribution network service providers,” the ESB said. Low-voltage cases were relatively few.
Research to understand the toll “overvoltage” places on devices is surprisingly scant given the transition of the grid to renewables – particularly with solar panels increasingly exporting surplus electrons – is well under way. (Last week, the entire Nem got half its power from rooftop photovoltaic systems, a first.)
A University of Wollongong team aims to close some of those knowledge gaps, testing hundreds of devices – from lightbulbs to microwaves and fridges – to gauge how they cope with varying voltages. Specialised ovens, set at 60C, heat the electronic components of various appliances to simulate an accelerated pace of degradation.
“If they all fail at the same time, well the voltage was not the cause – it was the temperature or some other mechanism,” says Sean Elphick, research coordinator at UoW’s Australian Power Quality Research Centre. “But if they fail at different times … we can make the observation that it’s the voltage that’s the issue.”
About 18 months into the experiment, led by PhD scholar Dinidu Jeewandara, the early findings echo those of previous research by the US military and others: high voltage shortens appliance’s operational lives. A 5% increase in voltage halves the life of incandescent lightbulbs, Elphick cites as one “extreme” example.
“Of all the appliances we’ve got here, vacuum cleaners have been some of the first to fail at the higher voltage levels,” he said.
Ty Christopher, director of UoW’s energy futures network, said electronic controls that convert alternating current from the grid to direct current were components particularly susceptible to excessive volts.
“You could end up with, for example, a washing machine … the motor in it is still perfectly sound but all the control panel’s power supply in it [fails],” he said. “You’re now having to retire that appliance earlier than you would have otherwise, due to being exposed to excess voltage throughout its life.”
Christopher was formerly chief engineer at Endeavour Energy, a company serving 2.7 million customers from Sydney’s west to the NSW south coast. Preventing appliances’ premature end could save Nem households $317m a year, or $35 each, he estimates.
Lowering voltage about 5% would also cut energy usage by 4% to 5%, saving about 3.8 terawatt hours of power. Retail savings would top $1bn, or on average $110 for each Nem customer, annually.
Yearly carbon emissions avoided would exceed 3m tonnes and peak demand on the grid would subside by 1.5GW – or about the size of the Liddell coal-fired power station that shut in 2023, Christopher said.
Gabrielle Kuiper, an independent distributed energy resources specialist and a director of the Superpower Institute, says most electricity companies see little advantage in lowering voltages.
“Consumers … [are] buying more electricity than necessary and paying more than necessary,” Kuiper said.
Another perverse outcome is that rooftop solar – which elevates voltage when panels export – may be curtailed as solar inverters are set to stop solar systems exporting at 253 volts.
“If we drop the voltages back down to [the 230v standard], that creates an enormous amount of headroom” for more solar power exports, said Kuiper, who pressed for changes while at the Esb and since.
Interestingly, the Victorian government found voltage was higher at night when solar panels were effectively offline, suggesting they were not to blame.
Kuiper said Victoria estimated high voltages cost its consumers $30m in extra electricity supply a year. With Victorians using more gas in their energy mix than elsewhere, residents in other states would probably save more if voltage curbs lowered power consumption.
Christopher estimated the cost of introducing Nem-wide live monitoring and a conservation voltage reduction standard at about $250m.
Victoria – which is also underwriting the UoW research – has seen enough to act. In 2020, the government set its electricity distribution code of practice to require distributors publish average voltage data annually.
By the following year, these firms had accelerated the introduction of so-called forward dynamic voltage management systems and other investments to manage voltage fluctuations better.
Victoria’s energy minister, Lily D’Ambrosio, said Victorians’ bills were already lighter by $13m a year.
“Proper voltage management is a simple tool to ensure we’re using our power more efficiently, saving Victorians money and helping to increase the take-up of the rooftop solar,” D’Ambrosio said.
Other states and the commonwealth, though, are waiting for results of a cost-benefit analysis by the Australian Energy Regulator (AER) as part of a consumer energy resources roadmap.
“[There] may be some positive impact on appliances, if voltage is managed so as not to operate at well above the standard voltage,” an AER spokesperson said.
“While we approve overall revenue for the businesses based on expenditure that we consider is prudent and efficient, we don’t decide how networks invest in voltage management.”
A frustrated Christopher, though, said “all you hear at the moment from many of the entities is ‘we need studies done’”.
”A lot of the time it’s driven by a lack of technical expertise,” he said. “In other cases, it’s driven by a lack of desire to want to change the status quo.”
