Biogas. Neither cheap nor green. Can this be changed?

Only one-third of its energy can be converted into electricity. The remaining two-thirds are lost in the form of the so-called residual heat. Meanwhile, coal does not generate greenhouse gases until the chemicals it contains begin to break down.

We like and value "organic" materials, don't we? This is probably the best prefix next to "eco" that does not require any additional marketing today, and itself is a marketing foundation in Indo-European languages. And then follow all the other ones. This has already been sold to us; there is no need to promote it further because there is already a long queue. On the other hand, for at least two decades, as part of the above-mentioned "eco", there was supposed to be an energy transformation, where - as a salvation for all humanity until windmills, solar panels and heat pumps save us - the word gas would be mentioned in every possible configuration.

Of course, February 2022 changed a lot in this matter, but gas still has not become a synonym for “bad mzimu”. You must learn to get it from sources other than the Russian Federation. It is also important to ensure these sources are as diversified as possible. So how did it happen that "biogas" has not been a best-seller for a long time and still is not a success?

When you are very young, you have dreams. As a high school graduate in 1990, I had many dreams, because the world suddenly turned in the right direction, and biotechnology appeared in Poland (and this word made me tremble inside). For the time being, it was a proposal to study it at several universities in Poland, including Wrocław. The door was wide open when you were a finalist in the Biology Olympic Competition. And I wanted so much... to co-create biogas (the idea of devoting one's life to something as precious as fighting against cancer was only the second in a line).

This text is about biogas. Isn't it nice and good to turn organic waste, stinking fish scraps, wood waste, cow, pig and poultry manure, as well as sludge from sewage treatment plants - which take too much space anyway and smell bad - into something functional? Giving warmth, light, and life? Turning all of that into something useful, energy-giving and (as I thought ...) potentially cheap substance?

Jakub Wiech, a specialist from the "Energetyka 24" website, informed me that Poland's delays in terms of energy transformation are also visible in the field of biogas. We are dealing here with a situation in which a country that is among the top twenty largest exporters of agri-food products, with a 10% share of farmers among its employees, has practically no biogas sector.

Approximately 300 biogas plants are operating along the Vistula River. As a comparison: in Germany there are about 10,000, in Italy about 1,600, and in France about 1,100. For this reason, the share of bioenergy in the Polish mix is negligible and reaches 1 GW. About the same amount of power is used in hydroelectric power plants in Poland. Meanwhile, the potential of biomethane production by the Polish agricultural sector is relatively large - estimated at approximately 4 billion cubic meters per year. Thanks to this, Poles could double their possibilities of internal gas supply."

The matter is therefore quite serious and completely incomprehensible. The thing itself is a source of considerable scientific discoveries. For example, a whole new anaerobic bacteria order was discovered recently in a "biogas factory" (order is broader than a family, genus and species), which could further increase the efficiency of biogas production. The discoverers proposed the “Darwinibiotices” name for them. It turned out that among the bacteria living in biogas plants, i.e. carrying out the anaerobic fermentation necessary to produce methane from the decomposition of the organic material, Darwinibiotices are one of the most numerous microorganisms in general. No one had noticed that before ... Because nobody was looking for it either.

To discover new bacteria, you must go places where strange biochemical processes are happening. Processes that none of us, homogeneous and metabolically boring as semolina cooked in water (creatures with cells equipped with a nucleus), could ever perform. Bacteria are all sticky, tiny and essentially round, but they have the most diverse metabolisms you could imagine. They differ from each other, so to speak, on the inside, not on the outside. They are quite different from us.

European specialists, mainly from the Dresden University of Technology, thanks to funding for the Micro4Biogas project, analysed 80 samples from 45 biogas plants scattered across Europe and found this microscopic Holy Grail. Representatives of Darwinibiotices were present in all samples, despite the differences and distances between the biogas plants from which they were collected. This means - there is no biogas without these bacteria, and if we worked on them a bit, there could be more of it from the same mass of bio-waste.
A laboratory in Lublin where various types of algae are grown to produce biomass needed to produce biogas at the “Centre of Excellence for Applied Physics in Sustainable Agriculture” of Prof. Bohdan Dobrzański Polish Academy of Sciences. Photo PAP/Wojciech Pacewicz
Now we need to briefly understand what biogas is and how it is produced. Science has poorly explored this process; it is the so-called Black Box because the role and dynamics of most microorganisms involved remain unknown. And since their metabolism is so diverse, the product of anaerobic fermentation produced by bacteria X can constitute food for bacteria Y, which will result in a compound from which bacteria Z will generate methane. In the case of the analysed European biogas plants, most likely one specific bacterial family within this new order (i.e. the Darwinibacteriaceae family) cooperates in the above way with the archaea present in the fermenter. Archaea are the third branch of the tree of life, next to bacteria and eukaryotes, just like the bacterial branch - it consists only of non-nuclear microorganisms. Bacteria would therefore produce metabolic compounds - it is not necessarily obvious which ones and in what proportions – which archaea could then use to produce methane.

The aim of the Darwinibiotices discoverers is to make biogas plants resistant to the conditions and biomass used for production and, above all, "less dependent on subsidies for commercial operation, which would provide a boost to renewable energies around the world". So, is biogas subsidised? Well, today bacteria make it free from waste (transport is almost negligible because these should be local productions). Wouldn’t it be cheaper to extract oil… which similar bacteria and geological processes did several hundred million years ago?

As scientists from Ghent University experimentally stated in 2018 in the leading journal "Energy & Environmental Sciences": "Biogas does not need subsidies." Unless we burn it – which also has bad consequences because methane would always produce carbon dioxide after burning it, and methane itself is also a greenhouse gas. Biogas is not as green as it’s painted, but I will return to this matter later.

In their calculations, specialists from Ghent used data according to which in 2018 the biogas combustion process was responsible for obtaining approximately 10 percent of "green energy" in the EU. Subsidies for this combustion then ranged from 20 Euro to 276 Euro per megawatt hour. Back then, it was from half to 6 times the price of that megawatt hour on the market. In the EU, burning biogas and producing electricity from it is still subsidised; nothing has changed since then. However, Belgian experts proposed that instead, biogas should become "a raw material for the production of chemicals, which would bring benefits to companies, governments and the environment". What is going on?

Well, biogas is essentially reduced carbon. If we want to synthesise organic compounds, it is energetically cheaper to synthesise them from already reduced compounds because they would have to be chemically reduced before synthesis. Moreover, only one-third of the energy contained in biogas can be converted into electricity. The remaining two-thirds are lost in the form of the so-called residual heat. Carbon locked in stable chemical compounds does not generate greenhouse gases until those chemical compounds begin to break down, generally by oxidation. Therefore, significant carbon sequestration occurs, cutting it off from easy oxidation and thus preventing from transferring it to the atmosphere.

The Center for Microbial Ecology and Technology (CMET) and the Laboratory for Chemical Technology (LCT) of the University of Ghent suggest that chemical companies convert biogas - taken directly from the network - into carbon monoxide, which is coal gas, one of the main raw materials in the chemical industry, based on organic synthesis. Another ingredient for organic synthesis would be methanol. They assume that although biomass is processed locally, its product is available everywhere, without the need for transportation, thus it could be used as gas injected straight into the network – like natural gas. The "Carbon Footprint" would be reduced here, because part of the fossil gas (i.e. the biomatter from hundreds of millions of years ago, trapped in the Earth's crust until it is extracted) could be replaced with biogas, processed with the organic matter of the present day.

“We can cover the world's methanol demand four times using the EU biogas. In fact, this would be a mix of different products: we estimate that we can sequester more than half of the world's industrial carbon dioxide emissions through the use of "natural biogas", that is - through the intelligent use of biomass" - say biotechnologists from Ghent who have already developed the necessary technology for this process. However, is it quite possible to reach "deep decarbonisation" just by using the production and transmission of biogas as an admixture to natural gas, used then for organic syntheses? Oh well, this depends on those who decide on combustion subsidies.

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As Jakub Wiech claims, "the political climate around bioenergy is changing. In the European Union's climate policy, biogas is classified as a renewable source. This is based on a simple calculation assuming continuity of production. To generate biogas, you need to have a certain amount of biomass, which - during its growth - absorbed carbon dioxide. However, when it is burned, a certain amount of greenhouse gases is released into the atmosphere anyway. This means that biogas is increasingly perceived as the so-called grey technology that should be rather abandoned, not supported.”

It is worth noting that the assessment of what is "eco" in terms of biogas has been changing for several years, which may be a disappointment for fans of the so-called biofuels, i.e. growing oil plants only to make substances poured into vehicle engines. I'm leaving aside all the automotive issues I know nothing about. Still, regarding the profitability of the processes - not so much for the wallet, but for the environment - scientists from Bangor University and the Thünen Institute in Germany commented on the issue in 2015 in the "Global Change Biology Bioenergy" scientific journal. Their calculations show that biogas obtained from waste is at least ten times more effective than biogas from crops in terms of reducing greenhouse gas emissions per hectare of cultivated land.

Then, and still today, in many EU countries, the subsidies mentioned above - for biogas combustion, called feed-in tariffs for bioelectricity - encourage the use of crops not for feeding people and animals but for the production of biogas in large anaerobic fermentation plants. In addition, mandatory “biofuel blend targets” stimulate the production of liquid biofuels from food crops.

To put it in a language used excessively in the documents of the European institutions - although this time prompting truths not necessarily accepted there - political measures here are not aimed at the most sustainable bioenergy options – which is to reduce dependency on polluting fossil fuels and focus on reducing greenhouse gas emissions. The so-called environmental efficiency, or even more so environmental sustainability, is a complicated topic that would require more than just one article. However, I can easily imagine that common sense and Mother Earth will be less offended - where 9% of the human population goes hungry – if the heating and biogas electricity, produced by home gas plants, use biogas generated from pig excrement and food waste, not corn. SIGN UP TO OUR PAGE As the authors of this study note, "anaerobic digestion of manure and food waste prevents emissions resulting from storing manure and composting food waste. [...] However, care must be taken to minimise ammonia emissions when storing and applying «biofertiliser» from digestate produced on land together with biogas in anaerobic digestion plants.”

Microorganisms that produce biogas in anaerobic digesters, as it turned out, live in highly organised biomes, where the well-being of one newly discovered type of bacteria determines the effectiveness of others. This happens in the organic world - you can't manipulate one element, just like you wouldn’t manipulate only one gear in a mechanism - consequently, everything will move. Bioengineering is one kind of manipulation, and the subsidy system is another. It is worth understanding that biogas is produced in a complicated and still not fully understood way; it would probably bring a better future for us if scientists were listened to and their calculations were carefully checked. It may turn out that they could save us a lot of money and our planet, and "bio" would be really green, not grey.

– Magdalena Kawalec-Segond

TVP WEEKLY. Editorial team and jornalists

– Translated by Katarzyna Chocian


Main photo: Construction of the Pomorzany sewage treatment plant in Szczecin in 2009. Biogas is produced in these chambers. Photo Marcin Bielecki / Forum
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