Oil products such as gasoline and diesel, which are produced in a refinery from crude oil, are used for our transport (passenger cars, lorries, shipping, aviation) and heat production (especially in industry, for example, oil refineries). Part of the petroleum refining products, in particular the naphtha fraction, is used as a raw material for the petrochemical industry, such as for the production of ethylene and propylene that serve as a raw material for plastics.
Liquefaction transforms energy carriers such as natural gas and hydrogen into liquid form, with a large number of applications in our energy system. An enormous infrastructure has also been built around liquid energy carriers. Oil drilling, oil and liquid natural gas (LNG) tankers, pipelines, gas stations, and combustion engines are all part of chains that help us meet our daily energy needs.
Because many sources of emission-free energy – such as wind, sun and nuclear energy – generate electrical energy, these sources are not directly compatible with the infrastructure built for liquid and gaseous energy carriers. To achieve a green energy transition, it is necessary to consider how the current function of fossil liquid (and gaseous) energy carriers can be replaced by renewable energy sources.
In parts of the economy that run on liquid energy carriers, far-reaching sustainability through electrification is achievable. For example, electricity can be generated from sun and wind, and cars can increasingly run on electricity in the future. The current energy infrastructure must then be adapted to large-scale wind and solar parks, large-scale storage in batteries, charging stations and electrical infrastructure.
Electrification is not yet possible in some parts of the economy. This includes fuel for aviation (kerosene) and shipping (especially heavy products from an oil refinery, such as fuel oil), road traffic with energy-intensive and demanding deployment patterns and production of high-temperature heat (for example, boilers for processes where high temperatures are required) in various industrial processes. Liquid and gaseous energy carriers are also needed for large-scale storage and transport of energy in order to balance supply and demand for energy everywhere and at all times.
To be able to use large-scale green energy generation from wind and sun for these parts of the economy, hydrogen offers a solution. This hydrogen must then be generated with the help of electrolysis with electricity that can be generated with solar or wind energy. After reaction with CO2, this hydrogen can be converted into a synthesis gas (a mixture of CO and H2), which can be further converted into liquid fuels via a Fischer-Tropsch conversion. Fuels obtained from biomass can also be used here.