The production of chemicals and derived products today is highly dependent on the use of fossil carbon. Industrial processes require carbonaceous raw materials to provide process energy for a variety of processes and to use the embedded carbon (carbon bound in the molecular structure) as a starting material for a variety of chemical building blocks for e.g. polymers or detergents.
The study "CO2 reduction potential of the chemical industry through CCU" examines in an explorative scenario which greenhouse gas reductions can be achieved in the global chemical and downstream industry if the entire demand for embedded carbon is covered exclusively byCO2 instead of fossil sources. In order to present the topic in a transparent and understandable way, major simplifications are made. Methanol (CH₃OH) is chosen as a representative way to cover the carbon demand for chemicals and downstream products with renewable carbon. It is a plausible scenario to assign methanol a central role in supplying the chemical industry of the future.
The investigated CCU-based production pathway includesCO2 capture as a combination of direct air capture (DAC) and capture from various point sources, hydrogen supply and the hydrogenation reaction for methanol synthesis. In CCU-based methanol synthesis, greenhouse gas emissions depend on the emissions from renewable energy production. The emissions of CCU-based methanol are 67 to 77% lower compared to the emissions of fossil-based methanol when using photovoltaic electricity produced at current levels. With a completely renewable energy system, the reduction can even be 96 to 100 %.
The annual global demand for carbon contained in chemicals and derived products increases from 450 million tons of carbon (Mt C) today to 1000 Mt C in 2050 according to the scenario. Meeting this demand with CCU-based methanol means an immense energy demand of 29.1 PWh/year. Major efforts are required to provide this amount of renewable energy.
If photovoltaic plants in the desert were used to generate the green hydrogen for methanol production, only 1.3% of the total area of the Sahara would theoretically be required to cover the entire carbon demand of the chemical and derived products produced worldwide.
With a completely decarbonized energy supply, this could save 3.7 Gt ofCO2 per year. Even compared to today's global emissions of 55.6 GtCO2 equivalent per year, these savings in greenhouse gas emissions are considerable. The result shows that CCU can be a promising technology to reduce greenhouse gas emissions in the supply of embedded carbon to the chemical industry, provided sufficient renewable energy is available. CCU-based carbon will be an important pillar of the future of chemistry that relies on renewable carbon, CCU, biomass and recycling. For CCU to make a relevant contribution to a climate-friendly supply of raw materials for the chemical industry, global photovoltaic and wind capacities must be rapidly expanded.
The study "CO2 reduction potential of the chemical industry through CCU" is available free of charge at www.renewable-carbon-initiative.com/media/library/
