UnEarth Magazine.

Words by Emily Feeke, Art by Emma Dalton.

From the London West End to the streets of St Andrews a rallying cry rings out- “Just Stop Oil”. Climate activists around the UK call for the government to stop all new drilling and extraction of oil and gas to decrease carbon emissions and mitigate the current climate catastrophe humanity is set to face. The campaign totes a very noble cause, specifically calling for the movement away from petrochemical-derived fuels for the transport sector. It does not, however, address other uses of oil and gas, specifically their use in the petrochemical industry¹.  

Termed a key “blind spot” by Dr Fatih Birol, there is a question of how we will make a vast array of fossil fuel derived products that are fundamental to modern life. From fertilisers to clothing and from tyres to digital devices, petrochemical-derived products play an integral role in the production of essentials. Furthermore, petrochemical derivatives are critical for many technologies which have been shown to be essential in the renewable energy transition. 

Despite the complexity of the petrochemical industry, there are 7 main chemicals from which it is composed. The primary two are ammonia (used in fertilisers) and methanol (used as a solvent) which are typically made from natural gas or coal. The remaining 5 are collectively termed high-value compounds (HVCs), as they are made from oil. They consist of ethylene and propylene (used to make plastics), and benzene, toluene and mixed xylenes (used in the production of health and hygiene products). 

As the global population increases, the demand for these products increases too, thus upping the reliance on oil.  Petrochemical-derived products have been set to account for over a third of the increase in oil demand in 2030 and half the increase by 2050! An urgent call to find renewable feedstocks for these chemicals is necessary, if the transition away from oil and gas is to be achieved.  

A renewable feedstock is one that can be easily regenerated. There is currently two primary feedstock routes that are being researched for the generation of traditionally petrochemical-derived products: biomass and by-product CO₂.  

The use of biomass is promising because it is a more sustainable hydrocarbon source but raises the question, where should biomass be obtained? Is it fair to use land that could be used for food to produce feedstocks? To overcome this issue, it has been proposed that agricultural waste could be used as the primary source of biomass. A further issue then arises, biomass feedstocks have higher oxygen content than those derived from fossil fuels. This oxygen must be removed in processing, a step which is not required for traditional feedstocks and presents a need for further processing technologies.  

Another feedstock route that is being considered is the use of CO₂ from carbon capture and storage (CCS) or siphoning it from the air. CO₂ is typically a by-product of industrial processes, and compared to traditional feedstock options, its use would result in a net reduction of CO₂ emissions. The CO₂ source would be coming from fossil fuels indirectly but as otherwise the CO₂ would be released into the atmosphere the use of these types of feedstocks would not contribute to the overall accumulation of CO₂ in the atmosphere. These technologies are limited by the fact that the separation and handling equipment are energy intensive.  

The use of by-product CO₂ has been implemented on a large scale with ammonia production. CO₂, a by-product of the ammonia synthesis process, is used as a raw material in the manufacturing of urea. Further to this, projects which adopt the use of renewable feedstocks are taking off, such as the Nordic Blue Crude project which takes carbon dioxide from the air and hydrogen from an adjacent ammonia plant to make hydrocarbons in a process entirely powered by hydroelectricity. Although the hydrogen used currently is produced from natural gas, in the future the hydrogen could be sourced from the electrolysis of water.  

In the quest for decarbonisation, renewable feedstocks hold hope for a more sustainable horizon. To accomplish this transition away from petrochemical feedstocks, however, research and investment are of utmost importance. Technology needs us to be poised to meet the needs of consumers when the UK finally takes the necessary step to “Just Stop Oil”.