Amid the coronavirus crisis and the calls for a green recovery, the energy transition has enjoyed renewed impetus, says ADBA’s (The Anaerobic Digestion and Bioresources Association) Charlotte Morton.
Biomethane and hydrogen could green the gas supply and they could do it together: biomethane could be used to produce green hydrogen while delivering carbon abatement today.
The coronavirus outbreak has populated the headlines of every news source over the past few months. Yet, the urgency of climate change has remarkably not been overshadowed by the ongoing pandemic.
On the contrary, terms such as green recovery, Net Zero, and green transition have dominated in the news, businesses’ plans, and Government’s announcements.
The new trend of aspiring to a better, safer and greener future has been ignited by the financial measures that governments must adopt to revive their economies from the current crisis and by the widely shared feeling that Covid-19 could be an unprecedented opportunity to move away from business-as-usual and create a new economy.
The new trend of aspiring to a better, safer and greener future has been ignited by the financial measures that governments must adopt to revive their economies from the current crisis and by the widely shared feeling that Covid-19 could be an unprecedented opportunity to move away from business-as-usual and create a new economy.
In this context and against the backdrop of the oil price crash triggered by the coronavirus pandemic and the price war between Saudi Arabia and Russia, the energy transition has been reaffirmed as a priority of the UK’s Government.
The International Renewable Energy Agency (IRENA) has defined the energy transition as “a pathway toward transformation of the global energy sector from fossil-based to zero-carbon by the second half of this century[1].”
Electrification will certainly play a key role in the energy transition, but as argued by the International Energy Agency (IEA), greening the gas infrastructure is just as critical[2].
The two main options to decarbonise the gas supply are biomethane generated by anaerobic digestion (AD), and low-carbon hydrogen[3].
The Committee on Climate Change (CCC) has repeatedly advised the Government that both will be needed to achieve Net Zero.
Ready to use
Unlike hydrogen, AD is a ready-to-use technology that is already producing biomethane by recycling organic wastes. Hydrogen has enjoyed unrivalled attention both in the media and in the Government’s plans to achieve net zero by 2050.
While its potential is unquestionable, it is not ready to deliver the carbon abatement that we are required to deliver to keep global warming below 1.5°C.
The main obstacles to the adoption of hydrogen lie in the distribution infrastructure and end-user equipment, both of which will need to be adapted to make it suitable to hydrogen transmission.
On the other hand, biomethane is indistinguishable from natural gas and so can directly replace fossil gas without any change to the existing gas infrastructure. Indeed, biomethane is already being injected in the gas grid.
The IEA stated “Biomethane is the largest contributor to low-carbon gas supply in the time horizon of the World Energy Outlook (WEO) Scenarios[4].”
Backing AD now could secure a third of the savings needed to meet the 2030 carbon budget and importantly, could contribute to the hydrogen future that the British Government is envisaging.
Backing AD now could secure a third of the savings needed to meet the 2030 carbon budget and importantly, could contribute to the hydrogen future that the British Government is envisaging.
The two technologies are not mutually exclusive. On the contrary, biomethane could be used to produce green hydrogen, that is hydrogen generated from renewable energy sources rather than fossil fuels. The main technique is steam reformation, which splits the methane molecule (CH4), into carbon dioxide (CO2) and hydrogen (H2).
So long as biomethane is used, releasing the carbon dioxide is carbon neutral. This is because CO2 from AD is what is called biogenic CO2. Such emissions are offset by the sequestration of an almost simultaneous (or at least close in time) equivalent CO2 absorption from biomass, unlike fossil carbon, for which the sequestration occurs over a geological timescale. Blue hydrogen is created through the same process of steam reformation, however using fossil methane. For this reason, the CO2 must be captured and stored for the resulting hydrogen to become carbon neutral, something that has not been achieved at scale yet.
Interestingly, once carbon capture and storage technology (CCS) becomes more economically viable, combining CCS with hydrogen production from biomethane could achieve the so-called “negative emissions”.
Steam reformation is also not the only method. The Australian Government has recently granted substantial financial backing – $9.41 million – to the world’s first project to turn biomethane into hydrogen and graphite.
Using an iron oxide as a catalyst, biomethane from sewage will be converted into renewable hydrogen, separating the carbon to produce graphite.
The process has been developed by the Hazer Group that has raised the funding to kick start the development of a 100-tonne-per-year low-emission hydrogen production facility, to create an alternative pathway to producing green hydrogen.
Two sides of the same coin
Commenting on the project, Hazer Group CEO Geoff Ward said: “The methane in biogas[5] is the same as the methane in natural gas, except one was created by the breakdown in organic material between 20 and 60 million years ago and the other by the breakdown of organic material between two weeks and two months ago[6].”
Biomethane and hydrogen are two sides of the same coin, both have the potential to decarbonise the gas supply and the former can be used to produce the latter.
One last thing to consider is that biomethane is generated by recycling organic wastes. Food waste, manures, slurries, other agricultural wastes, and wastewater can be all converted into biomethane thanks to AD, preventing harmful methane emissions from rotting food and farm wastes.
The by-product of the process is a rich in nutrient biofertiliser – digestate – which can help restore depleted soils. Biomethane therefore has an equally important role to play in the creation of a truly circular economy as it does in the energy transition, and to achieve Net Zero we will need both.
References
[1] https://www.irena.org/energytransition
[2] https://webstore.iea.org/download/direct/2970?fileName=Outlook_for_biogas_and_biomethane.pdf
[3] As with electricity, hydrogen is only as environmentally friendly as the way it is produced. Only blue hydrogen generated using natural gas with carbon capture utilisation and storage (CCUS), and green hydrogen produced using renewables, are compatible with Net Zero.
[4] The World Energy Outlook (WEO) series is a leading source of strategic insight on the future of energy and energy-related emissions, providing detailed scenarios that map out the consequences of different energy policy and investment choices. The time horizon is between today and 2040. https://webstore.iea.org/download/direct/2970?fileName=Outlook_for_biogas_and_biomethane.pdf
[5] Biomethane results from the purification of biogas.
