King Island's Innovative Microgrid

Sitting in the middle of Australia’s Bass Strait, King Island features one of Tasmania’s last remaining true microgrids. The cutting edge microgrid is similar to that of Kotzebue, Alaska with its integrated wind and solar installations, with the addition of two 4.2 ton flywheels and a 3 MW lead acid battery energy storage system. Until recently, the battery was the largest in Australia. The microgrid load is around 2.6 MW and the island also has around 1 MW of residential rooftop solar and buys excess solar at a 1 to 1 rate, $0.25 per kWh – the same rate residents pay for their power.

A recent addition to the microgrid is a 200 kW demonstration wave energy device that has been operating since July 2021 in a bay near the town of Grassy. The Wave Swell system operates with very few moving parts making it an interesting innovation for ocean energy.

[bettybyrd]

How good is that Amanda! Very informative - thank you.

[patricknogara]

This is one of the better reports I have seen on the King Island Advanced Hybrid Power Station and their efforts in harnessing Renewable Energy - well done Amanda.

I understand King Island is now reaching around 65% R.E. penetration with frequent ZDO periods - the longest period reached so far being around 90 continuous hours.

*Imagine operating a power station and not hearing your diesel generators run for over 3 days*

I think that kind of silence would make most Power Station Operators very nervous. Fortunately they have had a few years to get used to it, on King Island.

Of course, the ZDO was initially made possible because of the "Flywheels" - though this label that doesn't properly allude to what Diesel Rotary UPS (DRUPS) systems do .

As Peter mention:
DRUPS systems are started from stationary like a normal generator though, as you can probably imagine, they take much longer to start given the massive flywheel that has to also be accelerated up to synchronous speed.
Once up to speed they synchronise to the grid like normal generators.
Once synchronised however, a DRUPS system opens its clutch which allows the diesel engine to be turned Off.
The alternator and flywheel keep spinning by drawing on some of the Renewable energy available in the system.
In this Online mode the Flywheel / Alternator act as a Synchronous Condenser providing all the nutritional goodness for a healthy grid.
It also acts as a Frequency Stabiliser because when online, for the grid frequency to change requires changing the rotating speed of the massive flywheel which is not easily done.

What Peter did not mention:
If the DRUPS system is Online and it detects for instance a sudden drop in grid voltage due to a sudden drop or loss of Renewable Energy, energy in the flywheel instantaneously begins being extracted and delivered to the grid to ensure uninterrupted power - this is the Uninterruptible Power Supply (UPS) function of the machine.

The intricacies of this process are fascinating: the flywheel stores so much energy that the DRUPS systems can deliver rated power for around 5-8 seconds using only the energy stored in the flywheel whilst at the same time engaging the clutch to effectively jump-started the diesel engine and bring it to synchronous speed within a matter of a second or two. At that point the DRUPS system has seamlessly transitioned into generating power for the grid and restoring the energy in the flywheel.

All this happens with a maximum of 5% deviation to the grid.

They're a very innovative bunch at Hydro Tasmania.

[closertothetruth]

id rather use wasted energy to make pure hydrogen which can be used later, years ago on a small scale in NSW government funded households with solar systems to do just that instead of pouring unused electricity onto the grid the power produced pure hydrogen gas instead for cooking and heating water ZERO toxic fumes like you have with burning LPG, natural gas.