I spent the last three years of my life almost evangelising about biomethane and more broadly, biofuels. Perhaps that is not the right word given that I am a Christian but basically I was trying to get people more aware about biomethane because of the benefits it could bring to the energy transition. It was something that was overlooked during the course of the hydrogen hype, and there had been very aggressive lobbying and campaigning against biomethane for some political and emotional reasons.
In the backdrop of the wars that are taking place in the Middle East now, the potential impacts on energy systems and markets, I want to revisit the whole biomethane story, sharing the good, and explaining some of the concerns away, while also identifying the concerns that remain, which won’t be dealt with by biomethane.
The Good
Biomethane is produced from anaerobic digestion (AD) of organic matter. It is a natural process though it can be rushed and optimised through temperature and humidity control as well as careful management of the substrate (whatever organic feedstock) put together under those conditions.
Left alone, these organic stuff would have produced carbon dioxide and methane anyways. The carbon dioxide is biogenic so it doesn’t add to global warming potential, but the methane does (and it’s 28 times more potent). So by capturing this methane, we are already reducing emissions of greenhouse gas (GHG).
But what’s even better comes when this captured methane is actually used to displace fossil fuel. And it does so in two ways. Remember I mention it the AD process produces carbon dioxide and methane? The carbon dioxide can be used in industries for making dry ice, for cleaning purposes, and even used as feedstock for some specialty chemicals. Traditionally, these carbon dioxide are from fossil sources, so getting it from biogenic sources reduces final emissions. At the same time, when biomethane is displacing the fossil methane, we further reduce final emissions when we combust it for energy or consume it for other processes.
That is quite a bit of GHG emission reduction isn’t it?
The Better
It doesn’t just stop there. The biogenic carbon dioxide can be used to produce other e-fuels including e-methane that will help increase the methane yield of the feedstock. The other chemical process pathways like gasification, methanation and all will play a role in enabling this. This provides a suitable commercial pathway for green hydrogen to help contribute to energy transition at this stage without having to refit the demand-side equipment. It helps kickstart the market without the transport logistics and infrastructure in place yet.
There’s more. AD produces a liquid slurry that is called digestate as a residue in the reactors. These are remaining organic matter that has been mainly stripped of the carbon content, but other nutrient content remains, making it suitable for use as a fertiliser. Traditionally, fertiliser is made using synthetic ingredients, including ammonium salts, featuring natural gas as a feedstock to the chemical process. By using AD digestate to make up for part of the fertiliser, we are reducing the use of fossil fertiliser and once again reducing final emissions.
As energy security and food security become a more relevant topic, we begin to see how biomethane wonderfully contributes to both the energy and food ecosystems. While we all wonder when the holdup at the Straits of Hormuz is going to end, we can start investing in the right areas that will help create the biomethane ecosystem, which can enhance our energy security and resilience, rather than squandering further resources trying to backstop our fragility.
The feedstock concerns
One of the most common issues around biomethane or biofuels in general is the challenge of having enough feedstocks. At Blunomy, I’ve conducted many feedstock studies and mapped feedstocks. The truth is that we probably won’t be able to meet all the gas demand through the biomethane that we can produce from existing feedstocks. But neither should we.
Just as we should not be relying on a single gas field or a single strait to transport all our gas. Biomethane feedstocks are naturally diversified from various sources, and policies could encourage more organic waste or residue to be properly managed upstream to produce more biomethane.
Moreover, we have not even begun exploring the possibility of growing novel crop feedstocks on marginal land that can be dedicated to energy. These crops serve to rehabilitate the soil, the land ecosystems while contributing to energy. The concern about feedstock limitations should not even feature at this moment when we have not even exploited a tiny fraction of it.
Perpetuating oil & gas interest?
Another political and emotive concern raised is that biomethane will allow the energy industry to maintain oil & gas infrastructure, further entrenching our capture by these companies. We should not perpetuate gas infrastructure and entrench ourselves in the fossil ecosystem.
More often than not, the infrastructure is regulated, and we simply need to have the right policy and governance in place to push them to serve the interests of the energy transition rather than the status quo. In many countries that have started introducing blending mandates for biomethane in the gas networks and pipelines, the largest gas consumers and even fuel suppliers have become the biggest customers for biomethane!
The methane slip concerns
So the feedstock limitation or concern around energy industry interests, isn’t something to fuss over. What we can and ought to fuss over, is the fugitive emissions, and methane leakages from continuing to use of methane for energy in the existing infrastructure. Biomethane is still methane, so while combusting it produces biogenic carbon dioxide, which we consider non-additive GHG, the release of biomethane into the atmosphere itself is still a GHG emission.
This continues to be a challenge and certainly contributes to rising GHG emissions. What we cannot always agree on is whether pushing to end the use of methane entirely is worthwhile.
There is greater consciousness of methane leakages precisely because monitoring has improved, sensing equipment is now more broadly available, and I believe the technology to upkeep the infrastructure has also improved. This is an issue to be resolved through better infrastructure, better management and better systems to ensure accountability, compliance and monitoring.
Biomethane will not resolve the issue of methane leakages, but I am not sure if this problem should be stopping us from exploring biomethane as a solution to all the other above issues that I raised. Natural gas continues to be broadly use, and the huge amount of gas infrastructure already invested into could rightly be used to serve the transition if we are willing to build this biomethane ecosystem.
I hope you’re convinced biomethane is something worth working hard to make manifest in the future we are all working for. It’s worth wondering, when we pay for energy, what are we actually buying? And whether cheap energy comes at the cost of fragility, environmental harm, lower end-use efficiency, and reduced resilience. Are we exhausting our resources, and the environment for what really matters to us?
Update (26 March, 11:18am): Initially the post mentioned methane is 12 times more potent than CO2 in global warming potential but that has been corrected to 28 times.