For some people, every silver lining has a cloud or three.
This week, it was widely reported that by 2040 the market operator forecasts that nearly one quarter of all the electricity consumed in the national electricity market could come from rooftop solar — a tripling of the current penetration.Â
A day later, the market rule-maker, the Australian Energy Market Commission, released a report into the 2016 South Australian black system system event which sought to paint only the problems for system security of rooftop solar and other distributed energy resources.
Let me count the ways:
The behaviour of load is also becoming more risky and uncertain. High penetrations of distributed energy resources such as solar PV, increasing levels of battery storage and smart load management systems are also increasing uncertainty in the overall behaviour of load relative to historic levels.
The behaviour of load in response to a disturbance event is also becoming riskier due to the response of distributed energy resources. Risk arising from the performance of distributed energy resources in response to disturbances is compounded by the low levels of AEMO and NSP visibility and control of these generating systems.
High levels of distributed generation also increase the risk as to the effectiveness of emergency frequency control schemes.
High penetrations of distributed generation have been identified as a new source of systemic risk for power system security. AEMO has identified a range of issues associated with DER for system security.
But wait – they did say one good thing about DER:
It is worth noting that the large scale trip of DER following the separation of the Queensland region in August 2018 actually helped in the control of frequency, and therefore delivered a resilience benefit.
In other words, they can do good when they’re off!
To be fair, these are all real issues, though it’s worth noting that there are multiple processes underway which will result in networks and the market operator having more visibility over DER. These include the DER register, various network projects to improve visibility of the low voltage network, and the rollout of smart inverters with cloud-based comms and volt-var and volt-watt capability.
The basic problem is that the AEMC seems to view DER as a problem rather than an opportunity when it comes to maintaining system resilience in the face of severe weather events or cyberattacks.
We don’t have to go far to hear a different voice:
Importantly, the change in energy storage – from rotating parts in large, centrally dispatched generators to distributed batteries may provide opportunities to improve resilience and reliability. Smaller and smaller segments of networks may become capable of forming grids and standing on their own, either permanently or for a period of time while the network is reconfigured and repairs are made.
 As the majority of supply interruptions are due to distribution network faults… lower level nesting also has the potential to significantly improve reliability in future if it can allow time for switching and repair on the primary distribution (generally 11kV or 22kV) network.
Hallelujah. Who said this? Why, the AEMC itself, in its 2019 Grid of the future report.
The problem here seems to be one of perspective.
The black system report is written from the perspective of the centralised, bulk supply system, whereas the grid of the future report is written from the perspective of end users, who are now increasingly also generators, storers and traders of energy resources. Maybe the staff who wrote the former should have talked a little more to the staff who wrote the latter.
Let’s not forget that the whole market is supposed to operate in the long-term interests of consumers, not the industry. That is the national electricity objective.
You could flip it around and say that from a DER perspective, the fact that upstream blackouts can have widespread downstream impacts is the real problem. So the solution is to protect local energy systems from remote impacts rather than reinforcing the transmission system.
Surely it is up to the AEMC to work out the combination of centralised and distributed resources which will offer the greatest resilience to severe weather events and cyberattacks at the lowest cost to consumers. At the moment, that kind of cost benefit analysis does not seem to be on their horizon.
Until then, people will vote with their wallets and increase their own resilience by buying rooftop solar and home batteries – hopefully in full awareness of whether or not, and for how long, they can be operated during blackouts.
That’s not much help to people who don’t have and maybe can’t have solar and batteries for whatever reason. Their resilience could, though, benefit through being part of solar gardens, community batteries and islandable microgrids. Let’s call them community energy resources.
Both DER and non-DER owners benefit from improvements in the energy efficiency of buildings and appliances, and by their ability to shift loads in response to price signals. The less energy you consume, the less you need to be protected from blackouts—and the less likely load shedding is when large generators are offline. This is another important facet of resilience that was overlooked in the black system report.
We need rules which recognise the value of DER in increasing system resilience, rather than denigrating them as problems while incentivising more investment in upstream infrastructure.
Mark Byrne is Energy Market Advocate at the Total Environment Centre
