In a recent trial of 'mini grid' technology, a group of eight Melbourne houses were linked to each other to form a self-sustaining, all-renewable grid completely independent of mains electricity. Electricity was drawn instead from combined solar and battery systems on the houses, which could even cover the houses without solar systems installed.
While the trial only lasted a few minutes, it was a successful test of the infrastructure's capability to disconnect from the main power grid, share electricity between the houses to maintain power in all of them and then reconnect with the grid at the end of it. Operated by Victorian energy delivery service business AusNet Services, the trial is just the first step in a process that will test the Mooroolbark mini grid's capacity to manage peak demand on the network, as well as incorporating additional households in the neighbourhood.
Of the eight houses involved, six were fitted with solar and battery systems, with the solar systems ranging between 3-4.5kWh and the batteries each having a 10kWh capacity. Two of the houses were completely without solar or batteries, meaning they had to rely on the electricity generated and stored by the houses around them. AusNet Services used a combination of a cloud-based central control platform and an inverter-based device known as a stabiliser to separate the Melbourne mini grid from the main grid. The stabliliser is the key to maintaining an uninterrupted power supply to the homes, with a smart battery storage system that's able to either absorb or deliver excess power as needed.
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While mini-grids aren't a new concept, most have had to rely on some kind of diesel or fuel-powered generator until this point. Being able to run this one off entirely renewable energy is a big step forward.
While energy networks obviously don't want mini grids like this to disconnect from the main electricity grid entirely, having more households able to share power from solar panels and batteries actually benefits them. It's a great way to manage peak demand on the network as well.
In times of heavy demand, such as extreme weather events when most people are at home blasting the aircon or heating, the grid needs to provide more electricity than usual and can even go down if the infrastructure isn't up to scratch. Previously, meeting peak demand meant building more expensive and, for most of the year, unnecessary power stations. With this technology, houses generating their own electricity can share that with their neighbours, removing the need to build further infrastructure.
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"The electricity network will continue to play an important role in our energy future, but we need to make sure it is able to support technology such as solar panels and battery storage for the benefit of all customers," said AusNet Services' Alistair Parker. "As customers choose to move away from more traditional forms of energy generation, we want to better understand how we can integrate new technology into the existing electricity network so we can improve reliability and security."