One of the challenges in seeing the many opportunities biogas offer us in dealing with climate change – dealing with waste sustainably, reducing deforestation, protecting the environment, and producing clean energy – is that it is such a diverse range. But we are going to be hearing much more about those possibilities this fall, when world leaders convene in Glasgow for COP26.
The World Biogas Association (WBA) is bringing a strong message – “There’s No Net Zero without Biogas”. If we made efficient use of biogas, we would reduce global climate change emissions by 20%, create a global sustainable industry worth GBP 1 TRILLION and millions of jobs, many of them in rural areas; deliver home-grown, distributed, storable and dispatchable green energy; treat wastes that otherwise would produce harmful methane by recycling them into green energy, biofertilizer and biochemicals; and decarbonize difficult areas such as heavy good vehicles and agriculture.
The WBA set out the possibilities in detail in a March 2021 report called Biogas: Pathways to 2030, and there was a huge virtual Biogas Summit last month.
The key to producing biogas is anaerobic digestion, which is the simple and natural breakdown of organic material that occurs in the absence of oxygen, much like the process that takes place in a cow’s stomach. It produces biogas (carbon dioxide and methane) and organic fertilizer called digestate.
By SNV – SNV, Public Domain, https://commons.wikimedia.org/w/index.php?curid=8793880
“By recycling organic wastes such as food, farm and sewage wastes, energy crops, crop residues, grasses, seaweeds and algae, anaerobic digestion extracts the energy in the form of biogas and turns the rest into biofertiliser, replacing the need for energy intensive chemical fertilisers, and/or higher value bio-products and chemicals,” the WBA explains. “Able to produce renewable energy constantly in the form of a gas, biogas can deliver energy in the form most needed – whether that’s baseload electricity and heat, or gas to fuel those areas that are harder to decarbonise, such as heating homes or fuelling heavy goods vehicles.”
Biogas always seems to have been one of those stories that plug along below the radar, and I’ve never understood why that is. Maybe it is because it covers so much territory – from food waste to human waste, which we’re not keen to discuss even if we call it ‘toilet resources”. Maybe because the innovation seems to have started outside North America. The Ashden Awards has been profiling biogas projects for a long time but while there has been some use of biogas on US dairy farms, I am not aware of much use of biogas to generate energy in the US more widely. (If you know more, do let me know.)
The first time I really grasped the cross-cutting possibilities of biogas was a decade or more ago, when I learned how Rwanda had transformed its prisons with help from the International Committee of the Red Cross. Rwanda’s prison population grew dramatically after the genocide, and housing all these prisoners and those awaiting trial brought environmental problems in terms of dealing with waste and problems with deforestation as the prisons used wood for cooking. It called for a rethinking of how the prisons were run, and that led the Rwanda Correctional Service to turn to biogas.
This video was made in 2008 when KIST won an Ashden Award for its work.
“Rwanda has 13 prisons with around a total of 60,000 prisoners, who previously consumed around 10 tonnes of firewood a day which was equal to a yearly cost of around 1 billion Rwandan francs (USD 1.7 million), all this money just spent on buying firewood,” Cleanleap reported in 2015. “RCS started building large biodigesters in all 13 prisons, and currently biogas is used for more than 60% of all cooking fuel. Staff and inmates at the prisons now do not complain about the polluted air. In the past, when waste containers were full, the prisons used to have no other option than to release it in the surrounding areas which caused the human waste to flow to rivers.”
After realizing the success of biogas in prisons, the Rwandan government introduced the National Domestic Biogas Program (NDBP) focusing on rural areas helping them to cook using clean energy.
The program was created in 2007 in partnership with the Netherlands and German development organizations, SNV and GIZ with the goal of developing a commercially sustainable sector in which biogas replaced wood, and in which agricultural production was supported through using a bio-slurry fertilizer. There were three sizes of domestic plants, and government subsidized low income people who were willing to use biogas.
The program was expanded to all 30 districts and, in 2015, was being used by around 5,000 households.
The International Committee of the Red Cross helped Rwanda with the biogas prison project and used it in other prisons for which it had responsibility in Nepal and the Philippines, for the same reasons – it treats human excreta and kitchen waste in an environmentally-friendly and effective way while generating fuel for smoke-free cooking and a nutrient-rich fertilizer. The programs reduce prison costs and reduce deforestation. From 2002 to 2009, the ICRC helped build 13 biogas systems in 11 prisons of Nepal, the Philippines, and Rwanda.
The total cost of all five digesters in Nepal was US$12,960, for the Philippines US$27,700 and for a 500 m3 plant in Rwanda, it is about US$74,000, paid by the Ministry of Internal Security, according to a 2016 evaluation. Operational and maintenance costs are 2% of the total investment cost. The firewood savings are 22.5 tons/year in Nepal, approximately 40 tons/year in the Philippines, and 6.35–7.35 tons/year in Rwanda.
And in all these places, people who served time in the prisons have learned how biogas works and can take that knowledge home with them.