Any energy transformation process (electricity, gas, heat, cold) results in energy wastage.
Unavoidable energy is all of the energy that is considered to be wasted if it is not used as soon as it is available. For example, these are residual energies produced during industrial processes, or more surplus renewable electricity that cannot be stored.
Capturing and using this unavoidable energy, or recovery energy, is a major catalyst for optimising our energy efficiency. To do this, it is necessary to create connections between different sites that produce and consume the energy in order to optimise the energy efficiency of the whole grid. For example, we can capture CO2 emitted by an industrial site, then mix it with hydrogen to produce synthetic methane that can be used to replace natural gas to supply this or another site. This is known as a multi-energy grid.