Sustainable Economy

  • In our everyday lives, we use a wide range of materials such as plastics, detergents and cleaning agents, pharmaceuticals, and biofuels. A future sustainable economy can use either biomass or carbon dioxide from the atmosphere to produce these materials. The overall demand for the raw materials can be reduced by increasing the recycling rate.

  • An analysis of the demand and potential of biomass shows that third-generation biomass alone, i.e. the exclusive use of residual components from food production, is not sufficient to supply enough raw materials for a future chemical industry and for the production of biofuels. If development continues as previously, a bio-based economy will also have to rely on first or second generation biomass. These are food components such as starch, sugar, and vegetable oil, or plants grown on land where also food could be produced, such as grasses and wood. It is therefore inevitable that bio-based compounds will compete for the same land area as food production.

  • For a bio-economy, all the necessary technologies have been demonstrated at least on a pilot-plant scale. A bio-economy would therefore be technically and economically feasible with existing technology. Already today, various products are obtained from biomass in an economically viable way.

  • The direct capture of carbon dioxide from the atmosphere requires new technologies for which several proposals are currently being further developed. Due to the low concentration of carbon dioxide in the atmosphere significant technical challenges have to be overcome. As a consequence, the economic feasibility on a larger scale still has to be proven. The subsequent conversion of the separated carbon dioxide into chemicals requires a considerable amount of energy, but already works with production volumes of 5000 tonnes per year.

  • For a carbon-dioxide economy, no fertile land area would have to be used, since carbon-dioxide capture can be implemented anywhere, including for exampe deserts or permafrost regions. The required energy can also be generated sustainably, for example through photovoltaics in deserts.

  • Establishing a carbon-dioxide economy, however, will currently not reduce greenhouse-gas emissions as long as we burn fossil resources for energy use. Only after the energy transition could a carbon-dioxide economy make a sustainable contribution to reducing carbon dioxide in the atmosphere.

  • The repeatedly proposed use of algae either to capture carbon dioxide from the atmosphere or to produce chemicals from carbon dioxide turns out to be less efficient than comparable chemical routes. Algae are therefore not a suitable solution.

  • Both a bio-economy and a carbon-dioxide economy are in principle technically feasible and allow the material cycles of a circular economy to be closed.

  • However, as long as there are undernourished people, bio-economy is ethically questionable because of its competition with food production. Without a change in our behavior with respect to animal-based nutrition and number of children the problem of world hunger cannot be overcome. So we decide with our behavior whether we can realize an easily accessible bio-economy or whether we are forced for ethical reasons to aim for a carbon-dioxide economy with all its still unsolved economic and technical challenges.

The discussion presented here is based on a publication in ChemBioEng Reviews:
Pfennig, A.: Sustainable Bio- or CO2-Economy: Chances, Risks, and Systems Perspective.
ChemBioEng Reviews (2019) 6(3), 90-104.