Source : the age
Households with excess rooftop solar are selling cheap power to other homes and small businesses directly, beating the dwindling feed-in tariffs offered by retailers and delivering savings to non-solar consumers.
This is done through a virtual energy network (VEN), which in a Deakin University study over the past six months delivered, on average, 14c a kilowatt-hour to be shared between the buyer and the seller rather than boosting the profit of the retailer.
Deakin University associate professor Andrea La Nauze said the standard model meant that a household with rooftop solar was paid a feed-in tariff to export their energy to the grid, while their neighbour without solar paid their standard retail rate even if they were using energy at the same time.
“A virtual energy network connects those two neighbours [or any two customers],” La Nauze said.
“It’s a financial arrangement, so that instead of me buying my energy from the generic pool through my retailer at the retail price, I just buy it from you for a price that you and I agree.
“It is certainly using the grid. It is absolutely using the existing infrastructure that we’ve already invested in, which is one of the reasons why it is potentially so beneficial because it doesn’t require an additional set of hardware. All it requires is smart meters.”
La Nauze said the cost of electricity included a fixed and a tradeable component. The retailer still charged a fixed price to cover the cost of the network and a margin but the VEN enabled the tradeable part to be a transaction between individual customers.
Chris McGuigan from Moss Vale in the NSW Southern Highlands said she was both a buyer and a seller on the network, depending on the time of year.
“In winter, with the lower angle of the [sun in the] sky and the shorter days, I’m not able to generate as much [solar power],” McGuigan said. “During spring and summer, I’ve got so much excess that I’m delighted that someone else can use it.”
McGuigan said she traded electricity between her two homes free, and sold it at a good price to her sister 20 kilometres away and to various businesses including a cafe, a wellness facility and a winery, with connections facilitated through social media.
Energy Consumers Australia, which helped fund the Deakin study, said the virtual energy network was an example of how all consumers could benefit from the energy transition, not just those with rooftop solar. About 100 of the 300 participants in the study were non-solar households, La Nauze said, and many of them changed the way they used electricity.
“This is the idea of a solar sponge – we saw about a 20 per cent increase in their consumption at times in the middle of the day when it tends to be sunnier and there tends to be a lot of excess solar on the grid,” La Nauze said.
The grid has long had a problem of excess electricity during the day, when solar systems are pumping cheap power into the grid but demand is low. This has been partly alleviated in the past year because of the strong uptake of batteries.
From July, retailers in NSW, South-East Queensland and South Australia will have to offer opt-in Solar Sharer plans with three hours of free electricity during the day in another bid to prompt consumers to shift when they use power. A similar deal called Midday Power Saver will start in Victoria from October.
Sophie Beard, who owns a 1970s apartment in Brunswick in Melbourne, joined the virtual energy network for environmental reasons since her building does not have solar panels.
Her household of two working adults does not use much electricity and, while she could shift laundry and dishwashing to the day, she could not do much about needing to cook meals and use lighting in the evenings.
“It’s been good from the renewables perspective; so, in summer I was basically from 9am to 9pm getting zero-carbon electricity, which was great,” Beard said. “From the financial perspective, I’ve only been making about $3 a month, which isn’t a huge amount off your bill. The daily charges for the plan that it’s on are higher than other plans from the retailer but maybe as more retailers offer it, that will change.”
Tudor Goode and his wife, Gabrielle Hendriks, from Hornsby in Sydney are limited in the solar they can generate on their own home because they live in a leafy area on the south side of a hill. They recently installed a 6.6Kwh system, mostly so they could obtain the subsidy for a battery.
“I’m paying on average between eight and nine cents a kilowatt-hour for my electricity during the day, which is really great – we’re using all these people’s excess energy and they’re happy because they’re getting better than the crappy feed-in tariffs they get these days,” Goode said.
“I’ve got 32Kwh of battery, so basically during winter, the solar generates a piddling little amount – pretty much nothing – but I still use that cheap VEN energy during the day to charge up my battery and then we run on battery from 4 o’clock in the afternoon to 8 o’clock in the morning.”
The NSW and West Australian governments have also been paying incentives to get solar households to sign up to virtual power plants (VPPs). This is different to a virtual energy network because it gives the retailer control of the battery and reduces system costs overall, rather than being a specific transaction.
Uptake of VPPs has been slow, with NSW government figures suggesting 15 per cent of home batteries are connected.
McGuigan said she had been part of a virtual power plant in 2018 but left because it drained her battery. There was now better regulation of VPPs that offer more control to the owner but she preferred not to be “handing over control of a very important and very expensive piece of equipment to a retailer”.
La Nauze said a household could be in both a virtual energy network and a virtual power plant, and the projections about the volume of solar still to be added to the grid meant that all solutions would be needed.
“We are at the beginning of the transition,” she said. “The point of a virtual energy network is that there may be low-hanging fruit just by using prices to make the most out of the infrastructure that we already have.”
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Caitlin Fitzsimmons is the environment and climate reporter for The Sydney Morning Herald. She was previously the social affairs reporter and the Money editor.Connect via email.
