A trial program in Bruny Island, Tasmania, involving the installation of solar generation and battery storage at 34 homes, succeeded in cutting the island’s diesel use by 30 per cent over a peak period.
The Australian National University led the program, alongside Tas Networks, Reposit Power, the University of Tasmania, and the University of Sydney.
Bruny Island is connected to the Tasmanian distribution network via an undersea cable, which can be overloaded during the holidays when people visit the island. The previous solution was to run a diesel generator to manage the peak load constraint.
As an innovative solution, the CONSORT Bruny Island Battery Trial networked the 34 homes to distribute electricity when needed to the grid, as an alternative to the diesel generator.
Innovation Intelligence spoke to Dr. Paul Scott, research fellow, ANU, who explained “TasNetworks led the process of installing the battery and solar systems. There was a subsidy for the systems, where customers picked their own electricians to install the equipment, and got to decide what battery and solar system they wanted.
“As a result, TasNetworks could see how the rollout of residential battery storage and solar works when they do not control the options.
“Reposit Power provided the Reposit Box for each home. That is an optimiser which works within a single house, automatically charging and discharges the battery based on the best time to sell electricity back into the grid, taking into account retail tariffs and time of use charges.
“What we did was optimise that for the network as a whole, and all the houses involved.
“That involved finding a balance between what they would pay for electricity vs: what we will buy it for.”
The customers who consented to install the solar panels and batteries benefitted by being able to maximise their battery use by storing the energy not used throughout the day, and managing a time-of-use tariff.
The researchers created a Network Aware Coordination (NAC) algorithm to driving that optimisation over the Island.
Essentially, the algorithm negotiates with customers to resolve network limitations with the lowest possible cost, while customers were free to optimise their own consumption, ensuring that participation was in their best financial interests.
Future applications of concept
With the proliferation of solar panels and battery storage taken up by Australian households, the question of how they will be integrated into the system safely, and reliably, needs to be solved. The Bruny Island program demonstrates one way of doing so, while making sure everyone sees benefits.
In the wholesale energy market, generators will produce power at any moment to match supply and demand, which it often attempts to predict in advance. Unsurprisingly, that forecast is often wrong, as generators may trip out, or power lines go down.
When that happens the grid needs need to respond fast, and be ready. Systems which recognise a mismatch between supply and demand, and inject or absorb power into the network instantly, like the Tesla battery in South Australia, are key for this.
As coal power plants and gas turbines come out of the system, they need to provide a fast balancing service.
Dr. Scott explains, “We are looking at how we can do that with residential battery systems, without overloading the grid. Imagine a whole suburb of batteries injecting power at once.
“Our next project will scale up to a bigger problem, with many more batteries, potentially thousands.”