The white, upper bars represent the consumption of electricity, district heat, hydrogen or e-fuels.
Energy is needed to produce these derived fuels which is visualised in the energy sector. Electricity and district heat are transported via national energy infrastructure (grids). Hydrogen can be produced from electricity or from other sources.
E-gas and e-fuels are fuels produced from CO2 and from hydrogen obtained from electricity. An example is e-kerosene which is an e-fuel suitable for aviation. When combusting kerosene, water and CO2 are produced. To produce e-kerosene, this process is reversed and you start from water, CO2 and a lot of electricity to generate this new fuel.
There is no net CO2 emission from using e-gas or e-fuel when the CO2 to produce those fuels, is captured from the air or from sustainable biomass sources.