From Glasgow to Delhi to Sharm El-Sheikh
If we want to kickstart decarbonization until next year's COP 27 conference, we have to learn how to build solutions that work outside industrialized countries: We have to learn how to underengineer.
If we were to summarize the various responses to last month's COP 26 conference in Glasgow, “the expected disappointed” might sum up the majority of informed sentiments.
Amidst a smattering of positive news, including steps towards international standards for carbon markets, negative signals such as the last-minute change in wording from “phase out” to “phase down” coal power plants at the behest of India, stand out.
Closer to our own interests, hydrochar and hydrothermal carbonization were all but non-existent during the conference, and even pyrolitic biochar (pyrochar) received only a sideways glance. Despite remarkable research advances, the hopes of industrialized countries is still in high-tech, often overengineered, solutions.
The case of India
But the case of India proves that overengineered solutions won't get us closer towards the 1.5 degree goal. Seven of the ten biggest countries by population are in the “high” or “mid” brackets of the Human Development Index, projected to see rapid industrialization and energy-intensive lifestyle improvements in the near-to-mid future. For such a country the question often boils down to “coal power or no power”, with an obvious answer.
Currently India’s air is polluted in a way that it is harmful to breathe. Air pollution lockdowns were established in some areas as the concentration of tiny pollution particles (PM2.5) exceeded the safe level by a factor of 30 over a 24-hour period. In particular in densely populated northern India the air pollution spikes in autumn due to the burning of crop residues on the agricultural used fields.
Burning of crop stubble is a fast and easy way to get rid of these residues and to kill germs attached to them; but, as we can see with the air pollution, it is more than just a nuisance: it kills people breathing polluted air. And it is a waste: it is a waste of organic matter that could be used for a better planet. How so?
The organic matter was collected and accumulated in the crops by means of photosynthesis. The plants collect carbon dioxide and the energy of the sunlight and form carbohydrates like sugars, starch and cellulose and other substances like lignin. We only use a fraction of the crops: the seeds like corn, wheat, etc. To burn these residues means that the carbon dioxide is released together with the particular matter and smoke into the atmosphere.
Burning these residues causes the carbon dioxide to be immediately released back into the atmosphere together with the smoke. So for the environment protection 2 times bad: the carbon dioxide is there again and in addition we have locally high particulate matter values.
A better idea
By collecting the crop residues, carbon can be produced decentrally and easily by applying pyrolysis or HTC in simple plants. This yields biochar (pyrochar or hydrochar), which can have multiple uses for climate protection:
Either apply it directly to the fields again and deposit the carbon previously bound by photosynthesis together with the remaining mineral nutrients into the soil. The carbon is permanently removed from the atmosphere and now improves the soil in terms of water-holding capacity, structure and the ability to store nutrients.
The biochar obtained is fed to livestock as an admixture in the diet. In this way, ruminants become healthier and emit significantly less methane. The dung of the animals can then be returned to the fields and the unchanged excreted biochar additionally improves the soil.
Biochar can also be used as an energy source. The carbon is released again as carbon dioxide but it can save the use of fossil coal, for example in power plants, blast furnaces and cement factories. And the biochar is much lower in pollutants than the fossil coal.
Where dry biomass is abundantly available, pyrochar is the first, low-tech alternative to burning agricultural residue. In wetter climates, especially where farmers have to fend off invasive species, turning wet biomass into hydrochar might be the better fit.
Between the two, decentrally deployable and comparatively low-tech solutions, a country like India with depleting soils and emerging energy needs can turn biomass into soil ameliorants, biofuels, and potentially even become a net exporter of carbon offsets.
Sandhya Ramesh “Biochar could be the solution to crop burning that Indian farmers were waiting for” The Print (2019).
Md. Azharul Islam, Md. Sharif Hasan Limon, Marija Romić & Md. Atikul Islam “Hydrochar-based soil amendments for agriculture: a review of recent progress” Arabian Journal of Geosciences (2021).
Sivaprasad Shyam, Jayaseelan Arun, Kannappan Panchamoorthy Gopinath, Gautam Ribhu, Manandhar Ashish & Shah Ajay “Biomass as source for hydrochar and biochar production to recover phosphates from wastewater: A review on challenges, commercialization, and future perspectives” Chemosphere (2022).
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