Design and Optimization of a Sustainable Beccs Supply Chain in the European Union to Reduce the Stress on Core Planetary Boundaries

The raising interest gained by negative emission technologies and practices (NETPs) in academia, industry and international organizations is motivated by the ambitious goal set by the Paris Agreement[1] to reduce the global temperature rise by 2100 well below 2°C above pre-industrial levels. In fact, since the current scenario still features massive deployment of fossil fuels in hard-to-abate or costly-to-abate sectors, such as cement production or aviation, the removal of greenhouse gases (GHG) has become necessary to meet the target. In particular, research has been focusing on carbon dioxide removal (CDR).

In recent years, diverse NETPs have been studied and developed, from nature-based to more engineering options. Among them all, bioenergy with carbon capture and storage (BECCS) has been identified as the most promising one, because of its potential to remove CO₂ from the atmosphere and provide a sustainable and reliable source of energy. In a nutshell, BECCS involves the capture of the CO₂ from the atmosphere via photosynthesis during the plants growth; the biomass is then processed and transported to be converted into products, e.g., bioenergy or biofuels. The CO₂ emitted during the process is captured and stored permanently underground, creating a net carbon sink.

A highly detailed BECCS supply chain (SC) model has been designed and analyzed in the context of the European Union (EU-28 referring to 2018 data) to provide insights on the impact on the planetary boundaries (PBs)[2], [3] of the infrastructure associated with the carbon removal and electricity production on a multi-regional level. The model is based on a six-type feedstock biomass chosen among energy crops and residues types. The energy crops are cultivated on marginal land to avoid competition with food production and the amount available is based on the regional yield and land availability. The model includes five echelons (cultivation, processing, pelleting, combustion with carbon capture and storage) linked by transportation stages with three different transportation means. The CO₂ is capture employing a post-combustion technology with a monoethanolamine (MEA) aqueous solution and it can be stored in three different sites.

The goal of this work is to determine the configuration of an SC across all the EU members that meets a minimum CDR requirement in a given year and minimizes the transgression on the PBs. The CDR is shared among the countries of the EU-28 according to a cooperative approach. A linear programming (LP) optimization model has been implemented and solved in GAMS[4] interfacing with CPLEX. The analysis follows a life cycle optimization approach, considering the CO₂ removal as the functional unit, and focuses on nine PBs from cradle to grave. The solution has been enforced to be cost optimal using an epsilon-constrained method.

The results of the optimization is driven by the CO₂ removal: 473 Mt of biomass is cultivated in the EU in addition to 511 Mt of residues collected. The amount of biomass determines the amount of CO₂ removed from the atmosphere and it is constrained by the storage capacity in the EU-28. The solution to the minimum transgression scenario favors the deployment of biomass residues available in each country with the assumption that they are not held accountable for impacts from cultivation such as land and water usage – the main source of controversy of BECCS. At the end of a year the negative emissions provided by the SC amount to 0.95 Gt CO₂ with a total cost of the processing and infrastructure of 156 billion EUR in 2018. The supply chain is shared among all the countries of the EU-28 (except for Malta, which does not contribute at any echelon), however transportation of biomass across national borders only occurs from the land to the pelleting sites, while the combustion takes place in the same country of pelleting. The CO₂ is then distributed via a pipeline network across the EU to be stored. The cooperation among the countries allows taking advantage of the land of each country to grow or collect the biomass to meet the CDR target and to compensate for those countries which do not have any storage capacity.

After the minimization of the PBs transgression, we take a step forward and analyze the results in the context of the current transgression scenario in the EU focusing on three core PBs linked to CO₂: climate change CO₂ concentration, climate change energy imbalance and ocean acidification. We calculate the current transgression using the consumption-based emissions from the EORA database. The results show that the CDR provided by the SC can reduce the stress on the three core PBs by 20% where credits for the electricity produced are not even included.

In this work, we demonstrated that BECCS is a NETP viable option to meet the goal set by the Paris agreement while accounting for all the infrastructures involved in the SC in a very detailed optimization model. Additionally, the use of biomass on marginal land and residues allows for a sustainable feedstock which does not compete with food production. We proved that the collaboration among the states makes possible almost a 1 Gt CO₂ removed in a given year and can decrease the pressure on three fundamental PBs by 20%. The cost associated with the removal is shared among all the countries and they amount to about 11% of the GDP in the whole EU in 2018.

[1] “The Paris Agreement | UNFCCC.” https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-ag....

[2] J. Rockström et al., “Planetary boundaries: Exploring the safe operating space for humanity,” Ecol. Soc., vol. 14, no. 2, 2009, doi: 10.5751/ES-03180-140232.

[3] W. Steffen et al., “Planetary boundaries: Guiding human development on a changing planet,” Science (80-. )., vol. 347, no. 6223, 2015, doi: 10.1126/science.1259855.

[4] “GAMS - Cutting Edge Modeling.” https://www.gams.com/.