Rooftop solar in South Australia

“We’re currently running a large-scale trial involving more than 900,000 customers – it’s called South Australia!”. This was said in jest by Mark Vincent, Executive General Manager Strategy and Transformation at SA Power Networks, during a speech at Australian Energy Week 2022, but is something the utility believes is absolutely the case as South Australia leads the world in integrating flexible energy resources into its network.

Mark Vincent

“A lot of what is happening in SA is the canary in the coal mine for the whole Australian energy market,” Mr Vincent said.

“There are significant challenges and opportunities as we undergo a distribution revolution.” SA Power Networks is the state’s regulated electricity distributor, supplying a population of 1.7 million people across about 180,000km2.

It is also at the forefront of responding to the state’s, and Australia’s, rapid shift to customer energy resources (CER). South Australia is already successfully operating its electricity system with significant levels of renewable energy. In what has been a ten-year transition, large-scale wind and solar farms and rooftop solar now supply over two-thirds of the state’s electricity needs.

South Australia’s target is 100 per cent net-zero for the electricity sector by 2030, which is likely to be achieved much earlier, with customer energy resources playing an increasingly important role.

“Last year, we had multiple occasions when our network was a net exporter of energy to the transmission network, with almost the entire electricity needs of the state being met by rooftop solar,” Mr Vincent said.

“The trend is continuing – rooftop solar in the state is heading towards a capacity of 2GW. That is on a system that typically operates with a demand of only around 1.5GW.

“We suspect in the next five-to-ten years on every single sunny day in our state, the entire electricity system will be powered by rooftop solar. So, during the day, customers will be providing all the electricity we need and in the evening we’ll switch to other sources.”

This has huge implications in terms of managing a stable energy system. With all its connected solar and 30,000 home batteries, the distribution system in South Australia now is the single largest generator in the state.

“Electric vehicles (EVs) will be the next big thing and within less than a decade, could require as much as 10-20 per cent more energy to be carried through the network,” Mr Vincent said.

“This additional throughput could drive down unit prices to all customers, but equally could potentially double peak demand if it’s not managed cleverly.”

In South Australia, roughly a quarter of end use energy is currently being supplied by electricity. In the pursuit of decarbonising transportation and other energy applications, much of this energy will need to be carried by the electricity network – potentially doubling current throughput.

Leveraging latent capacity and flexibility

Managing the distribution network now involves not just managing supply for 900,000 customers with their diverse energy demand needs, but also managing their desire to contribute cheap and green energy into the grid from hundreds of thousands of small generators and fixed and mobile batteries.

“This is not easy to manage,” Mr Vincent said.

“The more of this you have, the more tech and smarts you need to manage it.

“We are getting regular periods when the state is supplying its entire power needs from wind and solar. And we hit net zero on the South Australian system regularly over the 2021-22 spring and summer.

The challenge and opportunity for network business is to ‘fill’ spare capacity available during low demand periods and to ‘stretch’ network capacity during high demand periods by utilising smart, flexible connections and sophisticated network management, rather than undertaking traditional network augmentation investments.

“To manage that currently, we need the Victorian Interconnector intact to enable enough gas generation to run and maintain system stability, with the excess renewables being exported interstate.”

Mr Vincent said there had been a high level of cooperation between the South Australian Government, the Australian Energy Market Operator, Electranet and SA Power Networks to manage these issues, but there was a realisation that the easiest place to manage them is in the distribution network.

“The good news is the investment in the 1980s and 1990s distribution network to meet air conditioning demand means we have untapped potential in our network – most of the time it is only running at 25-30 per cent capacity,” Mr Vincent said.

“If we are clever in tapping into that unused capacity, we can avoid the need for expensive network investment.

SA Power Networks has a number of complementary strategies in place to increase demand during peak solar generation periods (fill) and expand network capacity during peak solar generation and demand periods (stretch), improving network utilisation and offering greater network access and affordability to customers.

“Our challenge used to be moving energy from a distant source to where customers were using it and having enough to meet the evening peak, particularly in summer. Now, our challenge is to get the timing right to ensure we have enough generation available at the time customers want it.

“Our solutions are about ‘stretch’ and ‘fill’. Stretching the network’s capacity through smart network management and leveraging the network’s spare capacity – and filling it with flexible CER.”

SA Power Networks has achieved ‘stretch’ through investing in flexible or dynamic voltage management, whereas the ‘fill’ part of the strategy is reliant on customers exercising the significant flexibility available to them through increasingly intelligent energy appliances; including smart hot water, electric vehicle chargers, solar and batteries.

Innovative tariffs are being offered to encourage customers to more efficiently use network capacity, and SA Power Networks is also developing systems that allow real-time communication with smart inverters and VPPs to provide flexible export limits to customers rather than fixed limits.

Flexible Exports trial

An ARENA-funded trial is currently underway where SA Power Networks is testing the technical and customer issues associated with a Flexible Exports option for solar customers. Customers are being offered a choice of a 1.5kW fixed limit per phase, or a flexible limit up to 10kW. This allows exports to be managed down on rare occasions when there is network congestion.

The trial has already shown that customers could potentially export at 10kW 98 per cent or more most of the time, compared with the current fixed limit of only 5kW. Mr Vincent said that at the moment, SA Power Networks is focusing on the challenges posed by large volumes of solar, but believes the same type of system will be offered to manage EV charging.

“We see these dynamic or flexible limits as operating like guard rails. We have plenty of capacity – people can utilise that as much as they like, but there will be just a few occasions when we need to throttle back,” Mr Vincent said.

Mr Vincent said he also believes there is a lot of potential for the network in the take up of EVs as they have very significant batteries and will have a huge capacity to assist in managing load and energy supply.

Driving benefits for customers

“It’s really important in tackling the technical challenges of managing a distributed network that we keep the interests of customers as our focus – customers who are investing billions of dollars on solar, EVs, batteries and smart appliances,” Mr Vincent said.

“We want to maximise the value they get for that investment. We also want to keep it simple and easy for customers – we hear constantly from them that the electricity industry is incredibly complex and they don’t know who to trust.

“Equity is another issue for customers and us – there is a high risk of leaving customers behind – particularly renters and low-income earners who can be locked out of investing in new technology and appliances.”

The change is also about a whole new level of collaboration.

“We are talking to vendors, manufacturers, installers, the market operator and government in ways and depth that we have never before. This high-level collaboration will be essential in each jurisdiction as they seek to manage the changing electricity system,” Mr Vincent said.

“We are now offering services to the market operator that we have never had before, and we have capabilities to shift demand up – instead of load shedding.

“AEMO is looking to us to help increase load to avoid blackouts.

“It’s exciting and it’s invisible to customers. They may lose a few cents in exports, but in exchange, we have prevented a state-wide blackout with much larger losses for all customers.”

An affordable transition

Mr Vincent said a key focus of SA Power Networks was to deliver the transition without driving up costs for customers through substantial and unnecessary capacity investment.

“In SA we could have 11GW of flexible resources on a network designed for 3GW peak. If we get it right we can manage that through smart solutions, not extensive investment,” Mr Vincent said.

“We want to do it in a way that reduces energy and network costs for all. If we can double throughput we can significantly reduce the network unit cost for customers while delivering more support and services than ever before.

“We think the opportunity exists to solve the energy trilemma – providing abundant green energy, that is secure and reliable and more affordable than ever for customers.

“And we are absolutely convinced that our distribution network, built largely in the 1950s – 1970s, can take on a brand new purpose, supporting the renewable energy ambitions of our customers and state.”

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