Generating value from ferment CO2 may be closer to home than first thought

How best can wineries generate value from fermentation CO₂? Is it feasible for them to capture and use their own CO₂ instead of buying it – or even convert it into other value-added products? 

Those are the questions an Impact project developed by the Australian Wine Research Institute (AWRI), innovation and commercialisation consultants Impact Innovation and Wine Australia, hopes to answer. 

The CO₂ Impact project came about after many wineries experienced severe CO₂ shortages and price increases during 2023 when purchasing CO₂ for inerting tanks. 

Purchase prices doubled, and in some instances tripled; and some wineries completely ran out of CO₂ for short periods. The shortage was primarily caused by the main CO₂ recovery plant in South Australia being attached to a natural gas-fired power plant that stopped operating regularly. 

“Fermentations in large wineries produce 2 to 30 times more CO₂ in a vintage than those wineries would use in a whole year, so the question is whether the wineries could be capturing and using their own CO₂ instead of buying it, or could they be converting it into other value-added products?,” said project lead, Dr Simon Nordestgaard, Principal Engineer at AWRI.

In addition, fermentation CO₂ contributes 8 per cent of the grape and wine sector’s greenhouse gas emissions (see the Emissions Reduction Roadmap), and its capture is a unique opportunity in emissions reduction.

The first stage of the project was a scoping study of opportunities for CO₂ reuse, and investigating the status quo in other fermentation industries, such as the beer industry.

“This identified that the economics of large brewery-style recovery CO₂ plants are challenging because of the much more seasonal nature of wine production,” said Simon. 

However, the scoping study also identified that current commercial CO₂ production is primarily a by-product of fossil fuel refining and use, and that this presents a longer-term supply risk as the economy transitions to renewable sources of power. The early stages of this were experienced first-hand for CO₂ supply in 2023.  

The study also recognised that whatever wineries might choose to do with the CO₂ generated from ferments, purity and the technical challenges of collecting it are going to be important factors that are specific to the wine sector and moreover to Australian wineries and practices. 

“For example, unlike breweries, winery tanks are typically designed to handle only negligible headspace pressure, and lids are typically left open to accommodate CO₂ venting, pump overs and compressed air agitation, additions and other operations,” said Simon.

During the 2024 vintage, trials will be undertaken to understand if and how these challenges can be managed by wineries while allowing fermentation CO₂ to be collected and stored. 

The next stages of the project are yet to be finalised but may focus on purification and liquefaction for reuse and/or use of CO₂ for other value-added products such as algae or bicarbonates.

Simon said the ultimate aim of the Impact Project is to provide wineries with options and advice on how they might be able to generate value from CO₂, so it is feasible for them to implement.

“We want to best position the Australian wine sector for a future where there might not be outside sources of CO₂ available at reasonable prices.”

Want to learn more?

Wine Australia has been working closely with the AWRI and other research partners to apply a new, co-design approach to project development that focusses on delivery of value to end-users.

You can read more about the process here.