Despite the water cooling system, the flywheels from Mülheim have a very small footprint thanks to their optimized design. In Robertstown, they each multiply the inertia of the synchronous condensers by a factor of three. But even so, they’re just under six meters long. The length of the synchronous condensers is almost double that. “This creates a huge amount of space in the machine room that we can put to good use in other ways,” says ElectraNet’s Emms.
“Our design, however, also allows us to grow very flexibly in length when more inertia is needed,” Büttner adds. “We’re currently building a flywheel with a total mass of about 180 metric tons for Irish grid operator ESB Networks to help stabilize the grid in Moneypoint in Southwest Ireland. That will be a new world record for flywheels used in grid stabilization.”
With the two flywheels in Robertstown, ElectraNet has covered its requirements for inertia in South Australia for now, at least. But if the number of solar and wind farms there continues to grow as quickly as it has in recent years, they certainly won’t remain the only ones, nor are they likely to be the largest.