Sector Coupling

Sector coupling refers to the integration and coordination of different energy sectors – usually heating, industry, mobility and electricity. In a coupled system, these sectors are connected in a way that allows them to exchange energy with each other. The overarching goal is to drive the adoption of renewable energies by facilitating a more efficient and interconnected use of resources. For example, excess electricity from wind and solar power can be used to produce hydrogen through electrolysis, which can then be used as a fuel for transportation or heating. Similarly, waste heat from industrial processes can be used for space heating or to generate electricity.

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Coupling strategies

Electrification

Electrification refers to the substitution of fossil fuels as an energy carrier with electricity. In heating, for example, this means using an electric radiator or a heat pump instead of a gas boiler. This eases the transfer of energy between sectors as clean power can be used directly to power heat pumps or electric vehicles without the need for an intermediary, such as e-fuels. 

In addition, electrifying energy-consuming sectors also adds more flexibility to the overall energy system. With demand-side management technologies, this flexibility can be used to match electricity consumption with generation.

Power-to-X

Power-to-X, or power-to-everything, refers to the use of clean electricity to produce climate-neutral chemical energy carriers, such as hydrogen or e-fuels. This conversion makes power-to-x far less energy efficient than electrification. However, many synthetically produced clean fuels can directly substitute fossil fuels without the need to alter existing infrastructure and machinery. For example, a gas boiler may be operated with hydrogen instead of natural gas.

Sector links

Heating

Electrode boilers use electric currents to directly heat water, without the need for a combustion process. As the electricity is channeled directly into the water, electrode boilers are more efficient than other forms of electric boilers, such as heating rods (see below). Electrode boilers enable high temperature and the creation of steam. They are mainly used in industrial applications.

Heat pumps transfer heat from one place to another rather than creating heat themselves. They are extremely efficient at heating and cooling buildings but are still in their infancy when it comes to industrial applications. 

Heating rods, or heating elements, convert electrical energy into heat through the process of resistance. They are comparatively cheap but lack efficiency.

Power-to-Gas is the creation of gas using electrical power. This gas can be used in conventional boilers to replace fossil fuels. It is especially effective in cutting fossil fuels in industrial applications, where temperatures above 500°C are required.

Mobility

Electrofuels (e-fuels) are synthetic fuels that can substitute conventional fossil fuels. They are synthesized using a combination of hydrogen and captured carbon dioxide or carbon monoxide. While they are carbon-neutral across their entire lifecycle, they still produce local emissions. Moreover, they have an extremely low energy efficiency. 

Electric vehicles (EVs) are fueled by electricity, which is stored in an internal battery. This removes the need for conversions and renders them very efficient.

Power-to-hydrogen is the conversion of water into hydrogen using electricity. For this process, an electrolyser is needed.The hydrogen can then be used to fuel vehicles. Like other conversions of electrical energy into chemical carriers, it is rather inefficient.

Energy Optimization

Smart charging

Electric vehicles can provide a lot of flexibility to the electricity system as their charging can be shifted to times of abundant electricity via different EV charging strategies. This reduces the cost for EV owners and makes use of renewable energy that might otherwise be curtailed.

Vehicle-to-grid

Just like EVs can make use of surplus electricity, bidirectional charging allows them to act as a source of electricity when generation is scarce. This reduces the need for fossil fuel-based power plants, such as gas power stations. On top of this, compensating EV owners for their flexibility further reduces electric cars’ cost of ownership.

Seasonal storage

While converting electricity into chemical energy carriers leads to significant losses, chemical energy carriers are well-suited to store large amounts of energy over long periods of time. Hydrogen, for example, can be stored in caverns or depleted gas fields.

The effects of sector coupling

Sector coupling presents both opportunities and challenges to future clean energy systems. Integrating electricity, heating, mobility and industry is crucial to maximize energy efficiency and flexibility and ensure we can add the necessary share of renewables into the power mix. But it also requires more holistic and sophisticated solutions that take different requirements and complexities into account. Energy companies are expected to bundle services and reduce this complexity for end users to make clean digital energy solutions the obvious choice.