The International Energy Agency’s (IEA) two-degree scenario (2DS) requires a near-halving in the proportion of global primary energy derived from oil, coal and natural gas, from 82% in 2013, to 45% by 2050. In the same scenario and time-frame, the chemical and petrochemical sector (hereafter, the chemical sector) follows a very different trajectory to the energy system as a whole: total sector energy consumption doubles, but is out-paced by growth in its fossil fuel inputs, which increase by more than 105% (IEA, 2016a).
These differing energy consumption trajectories reflect two challenges associated with mitigating fossil fuel energy consumption and subsequent emissions of greenhouse gases (GHGs) in the chemical sector. Firstly, like other industrial sectors, the chemical sector already has direct and substantial financial incentives to minimise energy consumption. Readily available efficiency gains are therefore scarcer than elsewhere in the energy system. Secondly, in 2013, roughly 60% of the chemical sector’s energy inputs were in the form of fossil fuel-based ‘feedstock’ energy, which become physically embedded in its final products (IEA, 2016b). Traditional energy efficiency and fuel-switching initiatives can provide few energy and GHG savings with respect to feedstock energy use. A more holistic approach to resource efficiency would clearly be beneficial.
Using traditional material flow analysis (MFA) techniques, macro-scale chemical process characterisations and data from more than 100 sources across multiple disciplines, a high-resolution mass balance for the global chemical sector is constructed. The resulting model describes the myriad pathways that the sector’s fossil fuel feedstock inputs traverse: from initial transformations into primary chemical building blocks (ammonia, methanol, light olefins and BTX aromatics); through to the materials (fertilizers, polymers, elastomers etc.) and end-use sectors (agriculture, construction, packaging etc.) that permeate every element of our modern built environment. The model covers 87 chemical compounds, secondary reactants and by-products. The results are presented in a Sankey diagram, depicting global production quantities for the year 2013, in mass terms. Our model allows us to examine a different future for the sector, than that of the IEA’s 2DS. Using the MFA-based model, the impacts of simpler – and perhaps more economic – mitigation levers can be explored. After delineating the key features of the model and methodologies employed, we quantify the upstream impacts of hypothetical reductions in demand for some of the sector’s key downstream outputs: nitrogenous fertilizers and thermoplastics.
References
IEA (2016a), Energy Technology Perspectives 2016 - Towards Sustainable Urban Energy Systems, IEA/OECD: Paris [Online data visualisation] DOI:10.1787/energy_tech-2016-en
IEA (2016b), IEA World Energy Balances IEA/OECD: Paris, [Online database] DOI:10.1787/enestats-data-en
• Socio-economic metabolism and material flow analysis , • Circular economy
