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Decarbonising Australia’s waste sector via WtE

Hitachi Zosen Inova (HZI) is a waste-to-energy (WtE) specialist and has its headquarters in Zurich, Switzerland. Inside Waste talks to Amal Jugdeo, Business Development Manager at HZI’s subsidiary in Australia, to tell us more about its decarbonising plans for Australia.

What role does HZI play in Australia’s waste sector decarbonisation plans?

Through research and technology, HZI is driving resource circularity, decarbonisation and supply security for present and future generations. This is done closely with our parent company, Hitachi Zosen Corporation (HITZ). This workstream is aligned with global efforts to reduce carbon dioxide (CO2) emissions. In Australia, the Government has committed to developing a 2050 Net Zero plan and 2035 emissions reduction target with the aim of establishing pathways for transitioning to a Net Zero economy. Emissions from the waste sector, which contributes more than three per cent of Australia’s overall GHG emissions, will be included in the decarbonisation plans.

HZI contributes to meeting these goals through investment in research and technology advances in its decarbonisation portfolio.   

Tell us more about HZI’s decarbonisation portfolio and application areas.

HZI has the technology to capture CO2 from WtE flue gas and CO2 from biogas produced in anaerobic digestors that would otherwise be emitted to the environment.

In Europe, there are numerous projects in advanced stages of development where the captured CO2 will be transported via pipeline and stored either in saline aquifers or depleted oil and gas reservoirs.

The integration of WtE and carbon capture and storage could enable waste to be a net zero, or even net negative emissions energy source, according to the UN Intergovernmental Panel on Climate Change.

The Clean Air Task Force website has an interactive map showing the list of carbon capture and storage projects worldwide. In Australia, we lack the coordinated effort we see in Europe to deliver these projects at scale, so it will take some time before CO2 storage becomes a viable option.

Read more: Indaver sings HZI as EPC contractor for project

The CarbonNet Project in Victoria is a promising start.

Another pathway is to produce hydrogen by the electrolysis of water using electricity from a WtE plant or some other renewable source.

The hydrogen can then be combined with the captured CO2 in a biological or catalytic methanation process to produce synthetic methane, which can be used as a substitute for natural gas. The hydrogen produced by electrolysis can also be used directly as a renewable fuel.

Currently, it is primarily used in hydrogen fuel cells, hydrogen boilers and hydrogen burners.

HZI can also purify and liquefy the captured CO2, which can be marketed as a product gas for various industrial processes, including the food industry.

Do you have reference projects for these decarbonisation technologies?

In June 2023, we inaugurated our latest project on the liquefaction and use of CO2 in Nesselnbach, Switzerland. Another carbon capture project is being completed in Zörbig, Germany.

Furthermore, two ‘build-own-operate’ organics waste processing projects in Apensen and Blankenhain, both in Germany, are milestone projects in terms of efficiency.

Combined, these plants will produce in excess of 90 GWh/a of sustainable raw biogas through our anaerobic digestion process.

Approximately 5,800 tonnes of organic liquid gas for the vehicle fuels market will be produced from the biogas. A by-product of more than 8,000 tonnes of liquid CO2 will be captured and used as a substitute for fossil-based CO2 in industry.

Upgrading the biogas will reduce greenhouse gases, and it will be possible to claim and sell more than 40,000 annual tonnes of CO2 equivalents in the form of greenhouse gas quotas (GHG quotas) under new German legislation. The production chain is not only carbon neutral but has a negative carbon footprint.

We also implemented a power-to-hydrogen project with an alkaline water electrolyser at the WtE plant in Buchs, Switzerland.

The facility will produce 550 Nm3/h of green hydrogen – enough fuel for a hydrogen-powered car to travel 20 million kilometres every year.

The new green hydrogen production facility will be integrated into Swissgrid’s novel concept for steering demand and oversupply within the Swiss power grid.

When a primary producer goes offline, secondary producers, such as the Buchs WtE plant, are brought online to stabilise the grid.

So-called negative compensation is also possible if too much renewable energy is produced compared with the scheduled volume.

In this situation, the hydrogen facility will draw up to 2 MW electricity from the grid, meaning that renewable energy producers such as wind farms will not need to be taken offline immediately or at all.

Our projects for catalytic methanation for the client Inpex in Osaka, Japan and Energie Steiermark in Gabersdorf, Austria, are particularly worth mentioning because we were able to show our group strength in the renewable gas sector for the first time, with project participation and technologies from our entities in Japan, Switzerland, Germany, and Slovakia.

The Gabersdorf project was part of a research project on the direct methanation of biogas without a preceding separation of CO2 where 21 Nm3/h of green methane was generated and fed into the grid.

HZI also completed the construction of Japan’s largest methanation facility in Odawara, Kanagawa Prefecture.

The plant produced 125 Nm3/h of methane, which covers the gas consumption of approximately 3,000 Japanese households. It was the first methanation plant in the world to use carbon dioxide emitted from a waste incineration plant.

What are the biggest hurdles for these projects?

Cost reduction is the greatest challenge. For hydrogen and methanation processes to become a viable alternative to conventional fossil fuels, project costs must be reduced to an acceptable level.

Costs can be reduced through economies of scale – the unit cost of production decreases as the size of the plant increases.

Furthermore, carbon offsets and shared decarbonisation infrastructure, such as the CarbonNet pipeline, will be important in enabling a viable business case for these technologies and carbon storage.

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