Renewable gas has a unique role to play in advancing net zero, and Australia is investing in its future. However, as this fuel has many limitations and dangers, its application must be considered carefully for meaningful action on climate.
Is renewable gas cleaner than natural gas?
Renewable gas is a fuel produced from organic matter, primarily agricultural and food waste and landfill gas. Unlike fossil natural gas, renewable gas is “renewable” in the sense that human activity will keep producing such waste products. It is also known as ‘renewable natural gas’ (RNG), ‘biogas’ or ‘biomethane’.
In most cases, renewable gas has lower life-cycle carbon emissions than its fossil fuel alternative. However, it is still far more polluting than zero-emission energy generation, such as wind and solar. One reason is that both renewable and fossil gas are chemically identical and made primarily of methane. This potent greenhouse gas (GHG) is over 80 times more climate-polluting than carbon dioxide and, therefore, a leading driver of the climate crisis. In addition, both gases emit carbon dioxide (CO2) when burned for energy.
While capturing and using methane is better than allowing it to escape directly into the atmosphere, the GHG emissions from leakages and burning still contribute towards diminishing the world’s rapidly dwindling carbon budget. Overshooting this budget risks triggering the Earth’s tipping points, leading to catastrophic and irreversible climate breakdown. Therefore, regarding the scale of the climate challenge ahead, renewable gas is no substitute for tasks that can be powered by truly clean energy. If used where cleaner options are available, it risks delaying the urgent transition to reach net zero in time to avoid the very worst of climate change.
The role of renewable gas in reaching net zero
In certain sectors, renewable gas can play a unique role in helping to reach net zero emissions. This includes capturing landfill and agricultural methane emissions or decarbonising in difficult sectors, such as some metals. In such cases, it can avoid more emissions than it generates, leading to net-negative carbon intensity.
However, the most powerful solutions for net zero are emission-free renewable energy generation, such as wind and solar, and electrification, such as heat pumps and induction cookers. Should renewable gas displace or delay the uptake of these alternatives, it can slow advancements towards net zero. Therefore, it is essential to be cautious with the applications of renewable gas, says the Climate Council. This is particularly because the fossil fuel industry is branding renewable gas as “green” to mask the fact it is responsible for “one of the fastest growing sources of greenhouse gas emissions worldwide”.
“Rather than committing to substantive action on climate change… the fossil fuel industry touts renewable gases and other solutions that maintain the value of their sunk investments while buying ‘social licence’ to keep polluting, allowing these companies to maintain business as usual for as long as possible”, summarises the Council. While renewable gas has a role to play in net zero, “that role shouldn’t be determined by the existing gas industry vision”.
Where renewable gas can enhance net zero
- Organic waste biomass from agriculture and food typically produce climate-damaging methane emissions. Capturing this methane can prevent these emissions from escaping into the atmosphere while exploiting its potential to provide energy.
- In many cases, this organic waste would generally end up in landfill. Utilising its methane spares it from waste. The solid byproduct of renewable gas production is also useful as a fertiliser.
- Renewable gas can be the solution to reduce emissions in some sectors that are difficult to decarbonise by clean energy generation. This includes using it as a chemical feedstock and refining some metals.
The limitations for net zero
- Renewable gas availability is limited, and Australia does not produce enough organic waste to generate the volumes required. Global assessments indicate that renewable gas is only capable of meeting one-fifth of today’s demand for gas.
- While renewable gas can help reduce the demand for fossil natural gas, this is just one small role in a clean energy future. Leaders must prioritise investing in widespread electrification, energy efficiency and zero-emissions renewable energy.
- Continuing to burn gas in houses for cooking emits toxic air pollutants that can increase the risk of disease, especially in children. The harmful pollutants from these stoves can leak even when they are switched off.
- Renewable gas risks justifying delaying climate action. Some big gas users plan to reduce their emissions by mixing some renewable gas into their networks, while still burning it alongside fossil natural gas. Eliminating fossil fuel use is essential for the net zero transition.
Australia’s energy transition
Australia elected its Labor government with the mandate to take more decisive action on climate. This included strengthening Australia’s GHG emissions reduction target to 43 per cent by 2030, from 2005 levels. In October 2022, Australia also joined over 120 other nations in the Global Methane Pledge, aimed at reducing these emissions by 30 per cent by 2030 from 2020 levels.
Australia’s government is currently supporting the expansion of renewable gas in the country’s energy mix, with the aim to help reach these climate goals. However, its strategy includes supporting investment in projects to incorporate renewable gas and hydrogen into Australia’s gas networks. The evidence shows that attempting to decarbonise an existing gas network is highly limited in terms of meaningful climate action and risks justifying fossil fuel use. Investing in zero-emission energy would have a more powerful impact to reach these goals.
Australia’s renewable gas projects
Due to its classification, renewable gas projects are eligible for funding from Australia’s Renewable Energy Agency (ARENA). Some projects include:
- The Nowra Project, New South Wales. This was Australia’s first large-scale waste-to-energy biogas plant, converting farm and food waste into biomethane to produce electricity.
- The Malabar Biomethane Injection Project, New South Wales. The plant processes biomethane from Sydney Water’s Malabar wastewater treatment plant for injection into the gas distribution network. ARENA funded the project with AUD $5.6 million.
- Hazer Biogas to Hydrogen Project, Western Australia. The project will produce up to 100 tonnes per annum of low-emissions hydrogen using biogas collected from a wastewater treatment plant. ARENA funded the project with an AUD $9.4 million grant.