Recently, there has been a big push from the gas industry to promote ‘biogas’ (also known as ‘biomethane’ or ‘green gas) as a climate solution. Let’s cut through the political spin and look at the facts.
- Benefits of biogas include its value for curbing methane emissions, reducing waste, and as a chemical product unto itself.
- Though biogas (and hydrogen) has many potential benefits as an energy source, it is often co opted by the gas industry to mislead the public and prolong the life of fossil fuels in our energy system.
- Shortcomings of biogas include there not being enough, it being insufficient to reaching net zero, and it being used as a smokescreen for the gas industry to delay real action on climate change.
‘Biogas’ is a form of methane produced by the fermentation of organic matter that can be used as a renewable energy source, but not without conditions—especially in a political and fossil fuel context. The gas industry has spent decades trying to convince the public that gas is anything other than a fossil fuel causing climate change and harming our health in the process. As it begins to lose this fight, it has chosen another front to fight on: biogas. Biogas is a necessary tool in the fight against climate change, but it is vital to be cautious with it, particularly because the fossil fuel industry is increasingly using it to paper over the fact they are one of the fastest growing sources of greenhouse gas emissions worldwide.
Being renewable, ‘biogas’ and its dizzying array of aliases – biomethane, green gas, renewable gas – are gaining currency as the world moves to decarbonise. Biogas is distinct from the fossil fuel-based ‘gas’ that is piped into homes and businesses around the world. But conveniently, since biogas and ‘gas’ are more-or-less chemically identical, biogas can still be introduced into our pre-existing network. Biogas presents a number of opportunities for a renewable energy future, but it is no substitute for wide scale electrification or simply making our energy use more efficient.
As with other technologies like carbon capture and storage, biogas is often used as an elaborate distraction and a delay strategy. Rather than committing to substantive action on climate change, such as rolling out proven technologies like wind and solar, improving efficiency and electrification, 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 to maintain business as usual for as long as possible.
The most important thing to know about biogas is that it has limits. There is simply not enough biomass ‘fuel’ to generate the quantity of biogas required to replace our current usage of gas. Optimistic scenarios developed by the International Energy Agency show that biogas has the potential to replace just 20% – or one-fifth – of the world’s demand for gas. While it can play a part in reducing fossil fuel use, getting to net zero nonetheless requires massive reductions in gas use.
Biogas, Biomethane, and Green Gas versus Renewable Gas
The terms ‘biogas’, ‘biomethane’, and ‘green gas’ are all synonyms. They refer to the same product: methane produced by the fermentation of organic matter. It is ‘renewable’ since it is produced by organic fuels like food and agricultural waste that will always be generated in perpetuity.
Though biogas is a type of renewable gas, not all renewable gases are biogas. Another prominent renewable gas is hydrogen – yet another gas competing for investment and widespread rollout across the country. As with biogas, hydrogen’s potential is also misused and exploited by the gas industry.
Is biogas valuable in a renewable energy future?
Absolutely. Biogas will play a role, but that role shouldn’t be determined by the existing gas industry vision. Some of the benefits we stand to reap include:
- Capturing stray methane: The biomass that acts as a fuel stock for biogas is organic waste and comes from a variety of sources: agricultural waste, food waste, and wasted crops, all of which typically produce methane emissions. Methane is a powerful greenhouse gas, capable of heating the planet by up to 100 times more than carbon dioxide in the short term. By capturing, then using this methane (which is inevitably created from decaying organic matter), we can prevent these emissions from escaping to the atmosphere and exploit their potential to provide energy.
- Reduce emissions in difficult sectors: While wind and solar, electrification and energy efficiency will play a bigger role than biogas, there are some tasks that will be simpler to accomplish with biogas. This includes using it as a chemical feedstock, and in the refining of some metals. Biogas is a valuable resource to reduce emissions in these areas.
- Reduces waste: In many cases, the biomass used to produce biogas would typically wind up in landfill, its nutrients not necessarily circulated through the ecosystem. By utilising the methane produced from this product, it’s spared from waste. Further, the solid byproduct of producing biogas, the digestate, can be used as fertiliser.
Does biogas come with its own problems?
Of course. There are several important limitations to biogas.
- Limited availability: As mentioned above, Australia does not produce enough organic waste to generate the volumes of biogas required to satisfy today’s demand. Optimistic global assessments of the future availability of biogas indicate that it is only capable of meeting one-fifth of today’s demand for gas.
- It can’t reach net zero alone: Because of this, while biogas may play an important role in our clean energy future, we will still need to invest very heavily in electrification, energy efficiency and other forms of renewable energy. To limit climate harm is to replace virtually all consumption of coal, oil and gas with zero emissions alternatives. Biogas can help reduce gas demand, but there’s much more that is needed to reach zero.
- Biogas is being used to justify delaying action today: Plans by big gas users to reduce their emissions by mixing a little biogas into their networks are being used to delay the inevitable transition to a zero emissions energy system. What is ultimately needed is a plan to eliminate the use of fossil fuels – coal, oil and gas – wherever they are used today.