Wollongong City Council independent candidate Suzanne de Vive, who ran on a proposal for an entirely solar-powered state, has had the least support from voters, with the Ward 1 business coach receiving 4.55% of the mayoral vote at press time on September 20. 

Yet the ideas in her book, Power Suburbs, received a lot of airtime as the Illawarra Flame and all other media outlets reported on the five mayoral candidates’ visions for the city during the council election campaign.

In response, Ty Christopher, an electrical engineer with four decades of experience in the power industry, and currently Energy Futures Network Director at the University of Wollongong, has reviewed Power Suburbs as “enthusiastic but naive”, lacking “deep understanding”. Ty has also objected to “gaslighting statements” in the book about senior UOW scientists. 

While emphasising that he is “massively enthusiastic” about distributed solar, especially solar on homes and businesses, Ty said the idea that rooftop solar can power even all of Wollongong is just not possible. 

‘It is against the laws of physics’

“I feel the need to inject fact into the conversation,” Ty said. “Australia's leading the world on solar energy for our homes and suburbs. Around a third of Australian homes currently have solar panels on them. It's something that we should continue to really lean heavily into. It just makes compelling sense.”

But, like our current energy footprint comes from multiple sources – gas, petrol, avgas, diesel, electricity generated from various sources – so too will future energy systems. To imagine a silver bullet solution rather than silver buckshot, Ty said ignores “the practical realities of the different, many different ways in which we use energy in a distributed sense – for large-scale transport, in very dense site-specific applications, for large industry and large commercial centres, such as CBDs, where the roof to energy consumption ratio just never works – let alone 24/7 versus five hours a day of useful solar.

“We need big energy solutions to run a CBD, aluminium production, steel production, heavy industry, operating a port, all of those sorts of things,” he said.

“I don't understand how this is a pejorative: I've seen critics of offshore wind say, ‘Oh, but it'll all just be used to supply the steelworks’. To which I respond with, and that's a bad thing?

“That'll mean the steelworks is now green and not buying coal-fired electricity.”

Ty said the solution is: “Big energy doing big things, small energy doing small things and, yes, medium-sized energy doing medium-sized things.

“What we need in a clean energy future are multiple technologies, each of them playing to their strengths – small generators and small storage, doing the small things (that’s solar and batteries supplying homes). Big energy generation and big storage doing big things – that’s offshore wind, large solar farms, large onshore wind farms, creating bulk power, storing them in really big grid batteries and things like pumped hydro and using them to supply the big loads that are there 24/7.”

Engineering facts 

Wires connecting homes to the grid are the skinniest cables, as thin as a pencil, hence have the lowest capacity.

“Physics dictates that you can only flow so much current, so much electricity through any wire of a particular size. And that's regardless of the direction that the power is flowing,” Ty said.

“What that means is your home can also only export a certain amount of electricity before you exceed the capacity of the physical wire connecting it. Once you get multiple homes in a street at maximum, you then run the danger exceeding the capacity of the wires in the street. Once you get multiple streets doing that, you will exceed the capacity of what's called the substation, the power transformer just upstream, and so on and so on.

“As you step your way up through the electricity grid, what that means is solar on homes and locally generated energy is fantastic, but it's most efficient use case – and it's only real practical use case at scale – is to be reused in the suburb where it's created. Because as soon as you start trying to export it out, you start exceeding the capacity of the grid.”

And what happens when you exceed the capacity of the grid?

“Fuses will pop and the power will go off.”

Do the math

BlueScope Steel currently uses the same amount of electricity as 60,000 homes. BlueScope predicts decarbonising its operation will increase electricity use by 15 times, which equals 900,000 homes’ worth of electricity. There are about 130,000 homes in the Illawarra. Hence supplying BlueScope from solar would need almost seven Illawarra’s worth of electricity to be generated.

Wollongong city centre uses the same amount of electricity as 36,000 homes. The Wollongong Local Government Area has about 90,000 homes. So the Wollongong city centre would soak up the solar energy generated by 40% of Wollongong's households. Currently 30% of homes have solar panels. This means Wollongong can’t even potentially run its city centre off rooftop solar.

Great grid

Last year 40% of the energy in the grid came from distributed renewables. This means massive reverse power flows for a grid designed to one-way power flows. “It's certainly a testament to the resilience of the engineering,” Ty said. 

Fifty years ago its makers had never heard of solar panels and could not have imagined the wires being used this way.

“It's truly amazing that the grid is continuing to deliver 99.99% reliability given that it is operating so far outside its original design parameters.”

Read more

• For local politics, read Jeremy Lasek's report History in the making, with Labor’s Tania Brown poised to be new Lord Mayor. Plus, how a Call for informal votes went out on Facebook.
• For more about the clean energy transformation, watch UOW's Energy Futures Network Director Ty Christopher deliver the keynote speech at the inaugural Southern Highlands Future Network event on 7 September 2024. See WinZero Wingecarribee's YouTube channel.