Speaker
Description
Current economy heavily relies on fossil resources to satisfy energy demands of human societies. Reaching climate change mitigation objectives requires to shift to carbon neutrality through the development of a bioeconomy. Notably, such transition requires the substitution of fossil-based energies into biomass-based energies (e.g. biogas). However, reducing dependency on fossil energies through production and use of biomass energies can lead to undesirable pressures and impacts on the environment if biomass production relies on intensive agriculture. The latter depends on external fossil-based inputs to produce biomass and would be energy deficient if fossil energy use were replaced by energy produced with biomass$^1$. Another way of biomass production is possible by switching to agroecological systems$^2$. Such agriculture models rely on ecosystem services rather than industrial inputs and thus, would reduce dependency on fossil energies and improve efficiency of input used and energy production. Integrated assessment of agriculture models and associated biomass energy plants have to be performed to clarify the potential of agroecology to develop a sustainable and efficient bioeconomy. Clarifying the role and effects of developing ecosystem services on energy flows and efficiency in agriculture and bioeconomy remains poorly investigated.
Classical energy assessments are based on ratios between inputs and outputs like EROI (Energy Return On Investment). Some recent studies aimed to develop new assessment approaches accounting for internal and external energy flows in agroecosystems, but strong disagreements$^3$ exist on the way to represent and assess internal flows and poorly deal with the concept of ecosystem services. In this study, we present a new conceptual and operational framework for energy flows and efficiency analysis, accounting for internal energy flows, ecosystem services in particular. A first sketch of this conceptual framework is depicted in Figure 1, considering, like in Life Cycle Analysis, both a natural (ecosphere) and a technical (technosphere) subsystem. Furthermore, natural capital and ecosystem services are considered as energy carriers and flows respectively in the same way as fossil resources and industrial inputs$^4$. Then based on previous pioneering studies$^5$$^,$$^6$, we aim to develop original energy assessment indicators enabling to account for the part of energy provided by nature through ecosystem services vs. the ones provided by the technosphere through industrial inputs. For example, as already shown$^6$, assessment of the mineralisation rate of soil organic matter can be used to assess energy provided by some ecosystem services linked to the soil functioning.
Our framework will provide the researchers and stakeholders with an operational approach for the assessment and design of energy efficient agroecological systems connected to biomass energy plants. We will illustrate our approach by applying it to farms-biogas plant systems considering different agriculture models of biomass production: from conventional to agroecological ones.
References:
1. Harchaoui, S. & Chatzimpiros, P. Can Agriculture Balance Its Energy Consumption and Continue to Produce Food? A Framework for Assessing Energy Neutrality Applied to French Agriculture. Sustainability 10, 4624 (2018).
2. Therond, O., Duru, M., Roger-Estrade, J. & Richard, G. A new analytical framework of farming system and agriculture model diversities. A review. Agron. Sustain. Dev. 37, 21 (2017).
3. Tello, E. et al. Assessing the energy trap of industrial agriculture in North America and Europe: 82 balances from 1830 to 2012. Agron Sustain Dev 43, 75 (2023).
4. Dardonville, M. et al. Assessment of ecosystem services and natural capital dynamics in agroecosystems. Ecosystem Services 54, 101415 (2022).
5. Guzmán, G., Molina, M., Soto Fernández, D., Infante-Amate, J. & Aguilera, E. Spanish agriculture from 1900 to 2008: a long-term perspective on agroecosystem energy from an agroecological approach. Regional Environmental Change 18, (2018).
6. Hercher-Pasteur, J., Loiseau, E., Sinfort, C. & Hélias, A. Energetic assessment of the agricultural production system. A review. Agron. Sustain. Dev. 40, 29 (2020).
| Keywords | integrated assessment ; multi-criteria assessment ; cropping systems ; biogas |
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