How useful can Australia’s vast army of distributed energy resources be when the grid suffers a shock? A new study aims to find out.
More than 2.5 million rooftop PV systems are connected around the country and one estimate says about 110,000 of them include battery storage. This legion of distributed energy resources, or DER, is growing – but how effectively can these assets be recruited to help when the entire electricity system suffers a shock? A new study at the University of NSW in Sydney aims to understand the role DER can play as problem-solvers in the grid.
The project will look to identify how these assets respond to contingency events such as the sudden loss of a large generator or transmission line, while also assessing opportunities for DER and rooftop solar PV to further protect the NEM from such events in the future.
The study will improve data capture, assess inverter behaviour, inform the development of new standards and set up tools and frameworks for long-term monitoring of solar and DER asset behaviour.
University of NSW research associate Naomi Springer says it’s especially important to know how inverters are behaving during disturbances. “Inverters have a wide range of really exciting capabilities and we’re really wanting to understand what they’re doing at the moment and how we could potentially improve how DER can help support the system,” she tells EcoGeneration.
Part of the study will aim to determine how many systems – be they PV generation or storage – it takes to have a statistically significant impact on the grid in times of need. “That’s an area as an industry we need to think about as we are shifting to more and more decentralised energy and needing to use to understand what’s happening,” Springer says.
AEMO’s Renewable Integration Study has identified that high penetration of rooftop solar presents challenges to power system security and that the impacts of it are already occurring and expected to increase over the next five years. The researchers will assess inverter compliance rates, identify possible improvements to existing inverter standards and provide AEMO with tools to more effectively operate a power system incorporating high levels of rooftop PV.
The researchers will apply the definition of contingency events used in the national electricity rules, including non-credible and potentially credible contingencies. An example is the separation of South Australia and Queensland from the National Electricity Market in August 2018 following a lightning strike near the NSW-Queensland border.
“That’s the type of event where you can see really big voltage or frequency deviations and potentially widespread response from DER,” Springer says.
Community batteries haven’t been included in the study. “We’re not developing a model that will be relevant to community batteries.”
Data for the research will be supplied by software company SolarAnalytics and sourced from its network of residential customers.
“We’ll be looking at what is actually going on in the field and building on work that we’ve done over the last few years with AEMO and SolarAnalytics in that area,” Stringer says. “SolarAnalytics has a substantial customer base across the whole of the electricity market.”
Virtual power plants are already meant to be operating in this area, as well as earning revenue for their aggregator-operators for providing services to the grid, but they are still relatively immature. Springer acknowledges there is lots of opportunity for VPPs to do their bit to restore calm to networks in times of stress.
The Australian Renewable Energy Agency is providing $981,000 in funding for the study, which is expected to cost $2.1 million. The Australian Energy Market Operator and solar monitoring company Solar Analytics are also partnering on the UNSW project. The project will run over three years.