Alternative carbon sources (ACS) are increasingly considered necessary for the defossilisation of fossil-based chemicals. However, the potential and impacts of integrating ACS-based processes in existing petrochemical clusters are often overlooked. This paper aims to systematically analyse key techno-economic and environmental indicators associated with producing bio-based isobutene as an option to defossilise the production of methyl-tert-butyl-ether (MTBE) in the Port of Rotterdam, the Netherlands. The assessment is conducted at process and cluster levels. For this, the bio-isobutene (bio-IBN) process (358 kt/y of product), along with the existing fossil-based processes involved in MTBE production (i.e. the MTBE cluster), were modelled in Aspen Plus v12. The results show that under current conditions, although bio-IBN production could defossilise the MTBE cluster by c.a. 80 %, it is not cost-competitive compared to the current fossil-based process. Furthermore, deploying the bio-IBN process would significantly change the structure of the existing MTBE cluster, increasing by a factor of two or larger electricity, cooling water and bare land requirements. These requirements would affect the economic and environmental performance of the full cluster. The results emphasise the critical role of strategic change of new processes within existing petrochemical clusters.

The rising pressure to defossilize the chemical industry has driven research toward producing chemicals that use alternative carbon sources (ACS). However, the challenges and impacts of replacing already implemented processes and symbiotic relationships remain largely underexplored. This paper systematically assesses the impacts of defossilizing existing processes, both individually and simultaneously, in a propylene cluster in the Port of Rotterdam, the Netherlands. Nine fossil-based processes and three ACS-based processes (i.e., CO₂-based polyol, biopropylene glycol (bio-PG), and biomethyl-tert-butyl-ether (bio-MTBE)) were included in the assessment. Integrating a single ACS-based process enlarges the propylene cluster and results in an excess of upstream chemicals that are no longer required by the ACS processes. Still, relatively simple technologies can reduce total energy and water use, resulting in lower direct CO₂emissions and water consumption of the cluster. Deploying multiple processes in parallel can drive the full defossilization of the cluster, but it requires a complete overhaul. The results illustrate the extent to which combining ACS-based processes could change the layout of an existing petrochemical cluster, affecting its performance. The paper stresses the importance of assessing such deployments, considering the existing conditions in industrial clusters.

This paper investigates green hydrogen and bio-based sustainable aviation fuels, including their production technology and feedstock, in combination with Clean Sky 2 propulsion technologies and novel hydrogen-powered propulsion technologies. The impact that these alternative aviation fuels and propulsion technologies can have on greenhouse gas emissions is identified and the demand for alternative aviation fuels is compared with their expected availability, both until 2050.