In short
A brewery on the NSW Central Coast is using computers mining bitcoin to heat the water it needs to make beer.
Bitcoin mining is so energy-intensive it is banned in some countries, but the brewery uses excess electricity generated by solar panels.
The business says the process generates about $2,000 a month in income, which goes towards paying its power bills.
In the back corner of a busy brewery at Lisarow, on the NSW Central Coast, a set of computers is generating all the heat needed to make beer.
The computers are bitcoin miners that run huge numbers of calculations every second, and receive cryptocurrency for doing so.
The process consumes lots of energy, but the machines, run on solar power, actually help the brewers cut power costs.
"We don't always do things the traditional way," Hawkesbury Brewing Co operations manager Adam Neale said.
"We wanted to be on the cutting edge of doing something different."
The machines earn Hawkesbury Brewing Co about $2,000 a month, which almost covers its power bills.
The bitcoin mine only runs when the brewery has too much solar energy, which means it costs nothing to run.
"We hit a crossroads where we knew we couldn't save any more energy anywhere else," Mr Neale said.
How does it work?
Sean Foley, a professor of applied finance at Macquarie University, said mining cryptocurrency was a very energy-intensive process.
"[The computers] get really, really hot … because you're pumping so much power through these systems," Professor Foley said.
"You might be using in the order of 20 or 30 times what a regular PC would [use]."
Professor Foley said the heat could be harnessed as a useful by-product.
"It's a waste product, effectively, of the bitcoin mining process,"he said.
"If you can utilise that heat for some sort of purpose … for heating, that's fantastic."
While cryptocurrency mining is banned in some parts of the world because of the amount of energy it uses, the brewery only uses renewable energy, leaving no carbon footprint.
Mr Neale began exploring the idea to avoid the fees that were charged for sending excess solar energy back into the grid.
"It'd be nice to give it back to the grid and get paid handsomely for it but it doesn't happen so we need to be able to use that power to then power the factory for the rest of the day," he said.
Storing the solar energy in a battery was not an option.
"The big problem for us with having batteries is that there is alcohol on site. Flammability's always a problem. Insurance companies just don't like the fact that you're storing electricity," Mr Neale said.
Instead of batteries, the brewery installed 16 bitcoin miners into a tub filled with a non-conductive liquid that looks like water.
The liquid cools the computers, and in turn heats up to about 90 degrees.
A heat exchange process uses that liquid to heat the water used in the beer-making process.
"We found there was enough heat coming off those miners to heat our incoming town water supply," Mr Neale said.
"We can heat our water up and store it for days on end.
"Everything that we need to do with hot water is done via that process."
More potential uses
Mr Neale believes the technique could be applied in other ways.
"We can see the potential for this for public swimming pools, recirculation of hot water in apartment buildings [and] manufacturing," he said.
"If you need hot water on site and lots of it, it's a way of being able to produce that hot water for the day."
Professor Foley cautiously agreed.
"I can't see anything particularly wrong with it, I'm just sceptical as to whether the economics are going to stack up," Dr Foley said.
"If they're able to earn some small amounts of bitcoin each day and then sell them and they can see that that's profitable, then I wouldn't see any restriction for other activities.
"Whether it were other brewers or other people who need to generate heat through the day, utilising bitcoin miners to do so."
