Last Saturday (12 November) a storm knocked down a transmission tower in South Australia, cutting one of South Australia’s connections to Victoria and (almost*) isolating the state from the rest of the National Electricity Market (NEM). Currently, it is expected that the connection will not be restored until this Sunday.
Rare island occurrences like this are not necessarily a problem, and are not the current cause of power outages affecting tens of thousands of people in the state; these outages are localized, and are caused by downed trees and power poles. However, this means AEMO has fewer tools at its disposal to maintain grid stability.
So AEMO and distribution network operator SA Power Networks are pulling out stops to ensure the lights stay on, including the Remote Disconnection and Reconnection (RD&R) emergency backstop for rooftop solar (aka ‘ the Big Solar Button’ as Dr Nick Engerer of Solcast calls it).
The fact that the Big Solar Button was pushed is something that has gotten quite a bit of attention in industry media such as WattClarity and RenewEconomy, and SA Power Networks has even called on customers on Facebook to shut down their rooftop solar systems manually. – hand.
Understandably these events are highlighted – the tools being deployed are relatively new and still important. They have been put in place to provide some interim measures to help manage solar exports while South Australia waits for a second interconnector to be completed and powered – along with NSW.
This new interconnector will provide a significant backup contingency for AEMO to manage these events in the future. (Until this massive infrastructure project is completed – possibly 2026 – measures will be in place and available to handle minimum need events and situations such as when the state becomes an island.)
A snapshot of the state of rooftop solar management
At SwitchDin, we see a future where smart management of distributed energy resources (DER) like solar is just one part of the way things work on our grid – but now we’re only part there.
Looking at what happened in SA during and around this incident gives us a feel for the current state of distributed rooftop solar management ‘in the wild’ – and it’s even more interesting that it first appears.
SwitchDin supports all these solutions with a complete toolkit for energy companies. Below we look at the tools being deployed and how they support clean, distributed energy systems through:
Making it possible for distributed energy assets to have an active, integrated role in how the grid works
Enables smart management of fleets of assets – even with mixed brands and types of equipment
Delivering value for end users by allowing them to be participants and beneficiaries of this ‘brave new grid’, where they can use their solar and other assets for themselves (such as self-consumption ) while also providing grid services
Allows rapid scaling of DER management in grid operation for small and large sites
Let’s see what happened.
The Big Solar Button works as intended, but was always intended as an emergency backstop
The RD&R function is an emergency backstop introduced to solve the pressing problem of managing large amounts of distributed solar on the SA grid. On the scale of fair and balanced solutions for managing rooftop solar, it is located a notch above the ‘zero export limits’ and a notch below the more sophisticated Flexible – or ‘Dynamic’ – Exports method, where the SwitchDin is an important enabler ( more below).
In terms of its function during this islanding event, SA Power Networks confirmed that RD&R did what it should have: It allowed them (at AEMO’s request) to shut down large amounts of rooftop solar to help maintain predictability in grid operation through a chaotic moment – and keep the lights on for as many people as possible.
For system owners, turning off your solar in an emergency in the electrical system is a small sacrifice in the name of power continuity, which is after all the primary right of the network operator for the benefit of all connected to the grid. But it falls short of our collective vision of a world / grid where rooftop solar and other types of distributed assets are a living, breathing part of how people get their electricity.
The old-school alternative to this approach is to trigger blackouts in different substation zones of the network. However, only outages occur due to distribution network lines or other infrastructure being physically knocked down. (Great job, SA Power Networks!)
Here’s what RD&R looks like for an individual site. In theory, all homes and businesses with RD&R capability could still produce solar energy for self-consumption (‘self-consumption’) but in reality very few systems actually do so – so 100% cut off solar production in the middle of the day. which you can see below.
