People were dazzled when Elon Musk won a bet on the installation of what was described as the world’s largest battery adjacent to the Hornsdale wind farm north of Adelaide, in the state of South Australia.
The bet was that his firm, Tesla, could install the battery within 100 days of signing a contract, or the job would be free.
Now that the hype has died down and energy experts have had a chance to see the battery in action, there have been some raised eyebrows not because the battery didn’t work, because it worked so well. Detractors, however, were quick to point out that when fully charged the Hornsdale battery can meet the needs of roughly 30,000 homes for about an hour.
That’s not a long time. But what naysayers have overlooked is not the amount of energy the battery can store, but how fast it can deliver it.
Electric companies don’t intend to use utility-scale batteries as storage. They want them for something just as important: ancillary services. In other words, they want batteries to bridge the gap between the time a power plant suddenly and unexpectedly goes off-line (trips), and backup power from another plant comes online. That gap can be several minutes, maybe as much as half an hour.
Musk said shortly after the battery became operational that switching to the battery in case of a power outage would be so quick that most people would never realize the outage had occurred.
Now he has been proven correct. Within two weeks of the battery’s installation, a unit at a coal-fired plant suddenly tripped and stopped supplying electricity. Musk’s battery was able to pump 7 MW into the national electricity grid within 140 milliseconds. A few weeks later a different unit at the same plant tripped, and this time the battery delivered a burst of 16 MW into the system, again in milliseconds, less time than it takes to blink your eyes.
Musk’s company seems to be onto a good thing. Now there is word that the neighbouring state of Victoria has signed up for a somewhat smaller battery to be installed adjacent to a wind farm that is to be constructed northwest of Melbourne. That project will cost more than $270 million, and Neoen, the French energy firm that will build and operate the system, says that, without the battery, the project would not have gone ahead.
Some people have been confused by the use of the word “battery.” Don’t think of something the size of a car battery, for example. These utility-scale lithium-ion batteries are huge. The one at Hornsdale is made up of 640 individual — but linked — Tesla batteries. It can store 129 MWh of energy and covers nearly a hectare of land.
In its first full month of operation, the battery generated 2.42 gigawatt-hours of energy and consumed 3.06 GWh. There are losses associated with energy storage, so storage is a net consumer of energy. This can be described as “round-trip efficiency,” a measure of the energy out to the energy in. In the case of the Hornsdale battery, the round-trip efficiency is roughly 80 per cent, which is considered excellent.
For years people have criticized the idea of using wind or solar renewable energy because the wind doesn’t always blow and the sun doesn’t always shine. Battery technology had not yet advanced to the point where battery storage was an option. But recent developments, spearheaded by people like a Elon Musk, have changed that.
Now the technology has reached the point where Natalie Collard, of Australia’s Clean Energy Council, says the big lithium-ion batteries “show just how effective these new technologies are in responding quickly to support our existing power grid with backup electricity.
“Batteries will become a part of everyday life for households and industrial operations as they get progressively cheaper—and this will happen faster than most people think.”
Korky Koroluk is an Ottawa-based freelance writer. Send comments to firstname.lastname@example.org.