Slowly the world is waking up to the idea that waste is something you don’t always have to immediately throw away. With a little ingenuity it’s sometimes possible to create a valuable commodity out of what was once cast onto the scrap heap or poured down the drain. When it’s raw energy in any form that is extracted as a result, businesses can cut costs and – all together now – sectors of industry can do their bit to push down carbon emissions.

That’s exciting on its own, but what if the energy product is hydrogen? That would require lots of fresh water to be split by an electrolyser, and fresh water is not an industrial by-product. But there are plenty of processes that produce wastewater, just as loaded with precious hydrogen. It’s a lost opportunity that managers never ponder but a problem like that is irresistible to chemical engineering students. A Sydney trio say they’ve cracked it.

Calling their new company switcH2, University of NSW students Khushal Polepalle, Constantine Tsounis and Bijil Subhash are trialling an invention that can separate hydrogen from wastewater produced in beer brewing ahead of a pilot later this year. 

The secret sauce in the process is a proprietary catalyst developed by Tsounis and fellow PhD and switcH2 cofounder Subhash that can oxidise organics in wastewater. “We wanted to translate that into a package that would be suitable for industry,” Tsounis says. “It’s about designing the right catalyst for the right application.” 

SwitcH2 is targeting breweries as the “low-hanging fruit” for a technology that can produce energy from smelly leftovers, Tsounis says, because they must pay copious amounts of money to process this wastewater, on top of tariffs councils might impose on them for pouring it down the drain. “It allows us to really change the way that breweries see this waste,” he says. “It’s a resource you can unlock value from just by processing it the right way.”

From left: SwitcH2 co-founders Khushal Polepalle, Constantine Tsounis and Bijil Subhash.

Beer by-product

In the switcH2 system the pure water is oxidised and dissolved organics in the water are oxidised, “which means the overall energy input to produce the same amount of energy coming out is reduced, because it’s actually much easier to oxidise those longer chain organics rather than water,” Tsounis tells EcoGeneration. “The basic thermodynamics of organic oxidation is much more favourable than water oxidation.”

Most beer-drinkers are calmly ignorant of the raw materials and chemical alchemy expended in the stuff that goes down their necks, other than to sometimes claim they can detect toasted barley or organic hops. Like any other consumer product, however, there are plentiful by-products in brewing. Tsounis says every litre of beer is responsible for about five litres of wastewater. The 600 breweries around Australia produce about two billion litres of beer a year, translating to about 10 billion litres of wastewater. 

Energy accounts for one of the largest operating costs in a brewery, and the energy required to produce 100L of beer can power an average home for a whole day. The amount of carbon dioxide emitted from this volume of beer is equivalent to driving 100km in a car. 

Onsite power source

Whether or not investment in an electrolyser stacks up depends on the uses a brewery manager can find for hydrogen. Even for small breweries, Tsounis says investment might make sense if hydrogen is only used for heating, to replace or offset natural gas. Larger operations might be able to justify further investment so the hydrogen produced could be used to generate electricity, power transportation or to replace carbon-based fuels.

Of course, to maximise the effect of decarbonising a brewer would run an electrolyser using clean energy, via rooftop PV or a PPA, for example. As it monitors its test program at UNSW, Tsounis says switcH2 has started discussions with breweries and found some with onsite solar or a PPA are not using renewable energy to its maximum extent. “There are often times, particularly during the day in summer, when solar energy is not being utilised,” he says. “We allow them to adopt more renewables into their system.”

SwitcH2 is working on finding a brewery to host a pilot-scale electrolyser towards the end of the year. Tsounis estimates it could produce one tonne of hydrogen annually. The test unit at UNSW is capable of producing about 20kg of hydrogen a year, he says, and is being trialled using various types of waste from real sources at different parts of the brewing process. 

The oxygen by-product that comes out the other end still must be disposed of but will require treatment under “milder conditions” as the oxidation process will have taken care of some of that. 

Beyond beer, switcH2 sees potential in the volumes of organic waste produced by the fast-moving consumer goods sector, which includes packaged food and drinks. Looking even larger, steelmaking and mining processes that produce abundant wastewater and where hydrogen can be used directly are also in the group’s sights. “It’s not only can we process the waste but can we do something useful with the hydrogen.” A liquid or gas fuel with high energy density, such as hydrogen, is well suited to industries that can’t be easily electrified, he says. 

Business solution

SwitcH2 isn’t just aiming to sell its electrolysers and walk away from customers, he says; it is pitching a full business solution around the application of integration of the technology into a business. The company estimates implementation of a 5MW electrolyser in a brewery can treat up to 4 million litres of wastewater, thereby offsetting $1.1 million in grid electricity and reduce emissions by 3,000 tonnes of carbon dioxide when used to power the electricity needs of night time operation. 

Tsounis estimates a four- to six-year payback on technology with a lifetime above 10 years.

The Sydney-based start-up is one of four companies involved with business incubator Startmate’s climate accelerator. As part of Startmate Sydney 2020, switcH2’s founders have access to mentorship and a $75,000 investment from the accelerator.