“[The clutch] It’s like 1950s technology — it’s really boring,” said Westerman (“Boring,” for grid operators, is the highest form of flattery). “The marginal cost of putting this in is nothing compared to the cost of the plant.
A company called SSS has built these clutches for decades. One of them is almost operational in the state of Queensland, at the Townsville gas-fired plant, which Siemens Energy is converting in what it calls a “hybrid rotary grid stabilizer.” Siemens claims this project is the world’s first conversion of a gas turbine of this size.
This particular modernization took around 18 months and involved relocating ancillary components from Townsville to make room for the new clutch. So it’s not instantaneous, but it’s much easier than building a new synchronous condenser from scratch, and it’s about half the cost, according to Siemens.
Some new long-term storage techniques also provide their own spinning mass. Canadian startup Hydrostor hopes to begin a fully permitted and contracted project in Broken Hill, a town in inland New South Wales, early next year.
Broken Hill lent its name to BHP, which began there as a silver mine in 1885 and became one of the largest global mining companies. More recently, the desert landscape was the setting for Mad Max 2’s post-apocalyptic car chases. Now around 18,000 people live there, at the end of a long line that connects to the wider network.
Hydrostor will boost local power by excavating an underground cavity and compressing air into it; The release of compressed air drives a turbine to regenerate up to 200 megawatts for up to eight hours, serving the community if the grid connection goes down and otherwise sending clean energy into the broader grid.
But unlike batteries, Hydrostor technology it uses old generators and its compressors contribute additional rotating metal.
“We have a clutch specified for New South Wales because they need inertia,” said Jon Norman, CEO of Hydrostor. “It’s so simple; they’re like the same clutches as a standard car.”
Transmission grid operator Transgrid ran a competitive process to determine the best way to provide system security for Broken Hill if it had to operate off-grid, Norman said. This analysis chose Hydrostor’s proposal to simply insert a clutch when installing its machinery.
The project still needs to be built, but if new clean storage technologies could step in to provide that grid security, it wouldn’t all have to come from ghost gas plants that remain in the system.
“It’s a different feeling. [in Australia]— there’s an attitude we can do, go get ’em, ‘put me on the coach,’” said Audrey Zibelman, the American grid expert who ran AEMO before Westerman. “When you’re determined to say the best way to do it, rather than why it’s hard or why it doesn’t work, solutions appear.
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