Energy vectors play a crucial role in facilitating the movement and conversion of energy. As the U.K. transitions towards a net zero future by 2050, these vectors play a crucial role within a whole energy systems approach because they facilitate the movement and conversion of energy from one form to another. Defined as simply as possible: Energy vectors are the carriers of energy. These vectors enable the efficient transport, storage and utilisation of energy from various sources.
These are the key energy vectors that will be the bedrock for the U.K. in the coming era of dynamic grid and load conditions:
Electricity: Electrical energy has transformed civilisation and will continue to do so. It is a versatile and highly efficient energy vector, used for everything from lighting and electronics to industrial processes and transportation. It is the bridge between different energy sources and end-use sectors, providing flexibility in energy distribution.
Hydrogen: As the lightest element in the universe, hydrogen is often considered a clean energy vector because it can be produced from various sources. Hydrogen has long been produced from natural gas, or other fossil fuel sources, but also can be extracted from water through electrolysis. It qualifies as a carbon-free energy resource when electrolysers are powered by renewable energy sources, or when the carbon emitted from fossil processes is captured at the back end. Hydrogen has applications in sectors where direct electrification may be challenging, such as heavy industry, long-haul transportation and energy storage.
Heat: Thermal energy is a significant energy vector because of its necessity for heating and cooling in residential, commercial and industrial settings. District heating and combined heat and power systems are examples of how heat can be integrated into whole energy systems.
Liquid fuels: Liquid fuels like gasoline, diesel and biofuels are essential vectors for transportation, especially in sectors — including aviation, maritime and long-haul ground shipping — where electrification is not yet feasible. The conversion away from hydrocarbon-based fuels towards biofuels and synthetic fuels produced through sustainable processes are part of efforts to decarbonise this vector.
Biomass: Biomass can be considered both an energy source and a vector, as it is used to produce bioenergy in various forms, including solid biomass (wood pellets), liquid biofuels (biodiesel, ethanol) and biogas. Biomass can be integrated into combined heat and power systems and used for electricity generation, heat production and transportation fuels.
Natural gas: Natural gas is a versatile energy vector used for heating, electricity generation, and many industrial and chemical industry processes. Efforts are being made to decarbonise the natural gas vector by incorporating biogas and synthetic methane, or by capturing, storing or using the carbon emissions.
Chemical energy: Chemical energy includes various energy vectors stored in chemical compounds, such as batteries, fuel cells and chemical energy carriers like ammonia or synthetic hydrocarbons. These vectors are critical for energy storage, especially in intermittent renewable energy systems.
District energy systems: District energy systems are centralised systems that distribute thermal energy (hot water or steam) to multiple buildings for heating and cooling. They offer energy efficiency benefits and can incorporate various energy sources, such as waste heat from industrial processes, combined heat and power, and renewable energy.
Integration Is The Way Forward
In a whole energy systems approach, the goal is to optimise the use of these energy vectors, considering factors like energy efficiency, environmental impact, economic viability and system resilience.
This approach often involves integrating various vectors, such as combining electricity and hydrogen production, or developing multi-vector energy systems to meet the diverse and evolving energy needs of society while striving for sustainability and reduced carbon emissions.
Accomplishing a task as big as rolling back carbon emissions to levels not seen since the early 1990s will require a concerted and holistic approach spanning all energy vectors. This is what is meant by a whole systems approach.
System planning is crucial as power grids around the globe experience unprecedented challenges.