In a joint initiative between Jemena and Sydney Water, a demonstration scale project has been launched that could have far-reaching implications for gas networks.
The Malabar Biomethane Project will see the upgrade of the biogas produced from the anaerobic digestion process at Sydney Water’s wastewater treatment plant to biomethane, which will then be injected, stored and distributed within the gas network. The benefit being: it’s net zero carbon emission gas supply.
Jemena general manager renewable gas Gabrielle Sycamore explains how the biogas is upgraded.
“As organic material from wastewater naturally breaks down, it produces biogas, which predominately consists of methane and carbon dioxide, as well as other gases and constituents,” she says.
“The process can be accelerated through anaerobic digestion whereby bacteria more rapidly breaks down the organic material in an enclosed environment without oxygen. This biogas can then be processed to remove carbon dioxide and the other components to produce biomethane, which meets the gas distribution specification (i.e. it’s the same composition as natural gas).”
Once this gas is injected into the gas network, it can not only provide customers with access to renewable and carbon-neutral energy, the gas can be used on-demand to provide responsive renewable energy to meet heat, industrial, or responsive generation to support other forms of renewable generation, such as wind or solar.
“The green credentials of biomethane really stack up,” Ms Sycamore says.
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“The gas is carbon neutral and we expected this project will remove around 5000 tonnes of carbon emissions–that’s the equivalent of around 4500 cars off the road.
“This is a significant and positive environmental benefit in support of the New South Wales Government’s Stage 1 Net Zero Plan–to cut emissions by 35 per cent by 2030, compared to 2005 levels.
“We are also excited about this project’s potential to be scaled up. It could remove 11,000 tonnes of carbon emissions.”
Jointly funded by Jemena ($8.1 million) and the Australian Renewable Energy Agency ($5.9million), the project was announced in November 2020, with Jemena currently working with Sydney Water on logistics before mobilisation, expected in late 2021. The project is then set to commence in 2022.
Ms Sycamore says the project is anticipated to pave the way for establishing a renewable gas market as well as a certification system, meaning that customers can have access and choice when it comes to the sustainability of their gas supply.
“An important part of this project is to understand how the design and construction of the facility can be optimised to reduce future costs and hence to reduce the future cost of renewable biomethane,” she says.
“The project is also an important demonstration of how circular economies can be established to make better use of our organic waste.
“We anticipate that by establishing a renewable gas market, customers’ demand for renewable gas can support better management and utilisation of organic waste which will in turn support additional biomethane supply.”
Growing awareness of renewable gas among energy consumers is another important aspect of the project.
“Most people have a good understanding that electrons can be produced from renewable sources like waste to power, wind and solar,” she says.
“However, the understanding that gas (molecules) can also be produced from renewable sources is lesser known. The importance of renewable gas, is the optionality it provides gas customers who’s energy demand is often not coincidental with solar and wind generation.”
When compared to renewable hydrogen being injected into gas networks, Ms Sycamore says the direct advantage of biomethane from biogas is that biogas is a mature technology with a well-developed supply chain with existing and accessible feedstocks like municipal organic waste sewage and agricultural waste.
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“Additionally, biomethane is effectively the same gas specification as natural gas with no impact on metering or customer’s appliances,” she says.
“Whereas renewable hydrogen (produced from electrolyses) is a developing technology, and it requires consideration in terms of blending with natural gas in gas infrastructure.
“However, in the long term, renewable hydrogen has enormous potential in Australia because of our accessibility of low cost renewable generation like wind and solar.
“As the hydrogen industry scales up, hydrogen blended into the network is anticipated to make a significant contribution to the renewable gas market.”
In addition to Jemena and Sydney Water’s Malabar Biomethane Project, Jemena is developing the Western Sydney Green Gas project, based in Horsley Park. The project will use renewable electricity to produce hydrogen, which will be injected and blended into the gas network to power approximately 250 homes.
“This project is significant because it is multi layered,” Ms Sycamore says.
“In addition to demonstrating the use of renewable energy to generate renewable gas, we’ll be sharing with industry how we inject and store hydrogen in our natural gas network.
“We’ll also be making excess hydrogen available to the vehicle industry, and in mid-2020, we signed an agreement with Coregas and Hyundai to supply hydrogen gas to fuel Hyundai’s hydrogen fleet.
“Both renewable hydrogen and biomethane are anticipated to be an important part of enabling our customers to decarbonise their future gas use.”