Heard the one about farting cows being a major contributor to climate change? Well, we haven’t worked out a solution to that per se. But what if we told you that it’s possible to transform their manure, and other organic waste, into fully renewable, carbon-neutral biomethane that can power the gas appliances in your home?
Australia produces around 30 million tonnes of organic waste per year from domestic and industrial sources. This accounts for a portion of national greenhouse gas emissions.
Thank goodness that technology exists today to turn organic waste, including green waste, food industry byproducts and agricultural residues - into a biogas a renewable gas that can be cleaned and upgraded to biomethane that can be used as energy in your home.
Keep reading to find out how biomethane works and some frequently asked questions about this game-changing renewable energy source…
• What is biomethane and how is it different from traditional natural gas?
Biomethane has the same chemical properties as natural gas but is derived from biogas instead of the fossil fuel-based natural gas predominately used today.
Biogas can be produced from various forms of organic material, such as green waste, food industry byproducts, agricultural and industrial waste. Organic material is placed within large, enclosed tanks, free from oxygen where microorganisms break down the organic material and release biogas. When processed and cleaned, it creates a carbon-neutral, renewable energy source known as biomethane.
• How is biomethane produced or where does it come from?
Biomethane is derived from biogas. Biogas is produced through a biological process known as anaerobic digestion, where microorganisms break down organic material in an oxygen-free environment.
The resultant biogas is predominantly methane (60%), with the rest being carbon dioxide and trace elements of other products such as hydrogen sulphide, nitrogen, and oxygen.
Through a process called biogas upgrading, biogas becomes a nearly pure methane known as biomethane. Biomethane is essentially interchangeable with natural gas and can be seamlessly blended into existing gas networks and appliances without modification.
The difference is that biomethane is carbon-neutral, making it an effective method of decarbonising homes, businesses and industry.
• Why is biomethane considered a renewable energy source?
Instead of leaving waste to degrade in the environment and potentially release methane into our atmosphere, the process within aneorobic digesters captures this methane and carbon dioxide which we call biogas.
Once the biogas is cleaned and upgraded the resultant biomethane can then be blended into our existing gas networks and used interchangeably with natural gas. In doing so, it supports decarbonisation of hard to abate sectors, has the potential to generate skilled renewable energy jobs in the energy sector and can provide an economic opportunity in regional agricultural areas.
“Biomethane plays a role across multiple sectors,” says Jarrod Irving, our Senior Advisor - Renewable Gas Development. “And it’s not just energy into your home, it’s also playing a role in the circular economy. It reduces the impacts on the environment, through diversion from landfill and utilises existing organic material to decarbonise our network for our household, commercial and industrial partners.”
• What are the environmental benefits of using biomethane as compared to fossil fuels?
Right now in Australia, much of our food waste is sent straight to landfill, where it has the potential to releases methane into our atmosphere if not captured correctly.
Add to this, some industrial and agricultural activities also generate organic wastes – capturing these organic materials for use as a feedstock for biogas production, gives it a secondary high value use.
The list goes on. These are just drops in that waste-filled ocean.
The use? Vital renewable energy that allows us to continue cooking our favourite meals on gas cooktops, having our friends and family over for a summer BBQ, and enjoying instant hot water in our homes and businesses.
By limiting the impacts of organic matter into our environment and utilising it to decarbonise our gas network, biomethane has the potential to make a major contribution to Australia’s renewable energy targets.
• Is it better to compost organic waste rather than convert it to biomethane through anaerobic digestion?
While composting is a valuable method for managing organic waste (and an excellent way for households to manage their own organic waste and provide nutrients to their gardens), anaerobic digestion offers several advantages when it comes to larger scale waste management that make it a better outcome for both soil health and reducing emissions.
When it comes to handling large volumes of waste, anaerobic digestion requires less space and much less time than large scale composting would. And instead of the byproduct methane being released into the atmosphere, anaerobic digestion allows for it to be captured and re-used as biomethane. Last but not least, the digestate that is produced from the anaerobic digestion process is rich in nutrients and can be used to improve soil structure and fertility, similarly to compost.
So, in short – anaerobic digestion is a faster and more efficient composting process that also allows us to capture the methane to use as renewable gas.
• Are there any limitations with producing biomethane?
Although the science is straightforward - fill an airtight tank known as an anaerobic digester, then let the bacteria get to work to produce a methane-rich gas - getting the process right can be tricky.
Australia is in its relative infancy with biomethane, however, biomethane is being produced around the world today. But progress is being made, Jemena’s Malabar Biomethane Injection Plant, is the first demonstration project in Australia to produce it and inject it into a gas network. They have partnered with Sydney Water to upgrade biogas produced from organic waste at the Malabar Water Resource Recovery Facility.
Until the technology is adopted more readily across the country, the main limitations will be cost and scale. An uptake in biomethane and biogas plants, and subsequent partnerships to obtain the organic matter, will bring the costs down and increase biomethane supply greatly.
• To create biomethane you need energy to run the biogas plant, is that renewable?
For biomethane (or hydrogen) to be considered a renewable gas, projects like Jemena’s Malabar facility must receive GreenPower Certification. To receive GreenPower Certification a renewable gas facility must meet specific criteria (called Certification Rules) in the production of its biomethane or hydrogen when it comes to electricity consumption, water consumption and the management/use of any bi-products. So yes, the energy used to power the biogas plant is renewable.
In the case of the Malabar facility the Certification Rules under the GreenPower scheme are published by the Office of Energy and Climate Change, NSW Treasury. GreenPower is a national renewable energy accreditation program, administered by the NSW Government on behalf of the NGPSG made up of the New South Wales, Victoria, and South Australia governments, with the Australian Capital Territory, Northern Territory, Tasmania and Queensland governments as observing members.
You can find more details about the Malabar certification here.
• Are there any safety considerations?
The safe operation of our gas networks is the most critical thing we do. New technology and best practice network management systems ensure a high level of public safety and reliability of supply.
At AGN, we are committed to managing our networks safely for the community we operate in and for our staff. Our vision is to maintain a culture where managing health and safety is a way of life and where we are always looking to improve.
Given the benefits of biomethane, it’s little wonder why nations like the US, the UK and Germany are advocating strongly for biomethane and investing heavily in it as a renewable energy source. Australia has the potential to join them as leaders in renewable biomethane.
Australia is at a pivotal moment in its renewable energy journey. And the development of biomethane as a renewable energy source that also helps reduce our organic waste is a progressive step that highlights the sustainable possibilities for homes and cooking in the future, a future where our very waste can help power our homes!
Biomethane fueling the cooktops in the MasterChef kitchen marks a landmark first. Hopefully it can be a catalyst for public opinion, awareness, and ultimately a steppingstone towards effectively and efficiently decarbonising the gas in our networks that we rely on to power our homes and businesses.
A diverse, fully renewable energy landscape is possible for every home and business in Australia. Especially if we remain open minded about innovative technologies and sources like biomethane.
Learn more about biomethane here
All figures quoted in this article were correct at the time of publishing (May 06, 2024).
