As featured in our publication RePower London, Drees & Sommer's Simon Joe Portal and Mustafa Rashid discuss sector coupling and its role in decarbonising London to achieve net-zero by 2050.

The roadmap to the ambitious target of net-zero by 2050 is marked by clear signposts: the electrification of our economy and transportation systems, the expansion of carbon-free energy production, and the exploration ofalternative heat sources for our homes, and the decarbonisation of manufacturing and industry. Yet, while thesemilestones are clearly defined, the path to reaching them is less straightforward.

Sector coupling involves the integration of various consumer groups via centralised energy systems such as electricity, heating, cooling, and fuel, to create a more efficient and resilient energy network. This holistic approach not only enhances energy efficiency but also promotes the use of renewable energy sources, thereby reducinggreenhouse gas emissions. In cities like London, sector coupling can be a game-changer for decarbonisation.

There are various approaches to sector coupling, including CO2 capture, e-fuels, heat networks, and hydrogen. For example, producing e-fuels through CO2 capture in industries like cement production enables the integration of the industrial sector with other sectors, such as transport. This e-fuel can then be used to decarbonise hard-to-electrify transport methods, such as aviation.

Sector coupling also involves the strategic use of waste heat as a supply for district heat networks. By capturing waste heat from sources such as industrial processes, data centres, and even the London Underground, this heat can be redistributed through district heating systems to provide efficient and sustainable heating solutions forresidential and commercial buildings. This not only reduces the need for additional energy production but also significantly lowers carbon emissions, making it a crucial component of a holistic decarbonisation strategy.

The city of Neu Isenburg is a good example of how sector coupling works in action. Investors had commenced the construction of a new data centre in the region, with the computers at the centre generating up to 50 MW of waste heat that would typically be released into the environment unused. Recognizing this opportunity, a concept, led by Drees & Sommer, was developed to utilize the heat generated to supply the entire city and its surrounding area with heating throughout the year. The system employs heat pumps and a region-wide distribution network to deliver heatto homes, offices, and industrial centres. This innovative approach not only significantly reduces the carbonemissions of Neu Isenburg but also offers substantial cost savings and improves the data centre’s carbon footprint.

For the UK the use of power-to-gas technology, where surplus renewable electricity is converted into hydrogen through electrolysis, will be key. This hydrogen can then be used as a clean fuel for transportation, heating, or even reconverted into electricity when needed. This process not only provides a flexible storage solution for renewable energy but also creates a versatile energy carrier that can be used across different sectors, such as industry, allowing them to operate in a carbon-free manner. In London and other urban areas, surplus renewable electricity that is converted into hydrogen could be used to power public transportation, reducing the city’s reliance on fossil fuels. In times when no renewable energy is available, stored hydrogen could also be used to power the city via converting back to electricity or providing building heating.

Sector coupling offers a promising pathway for London to achieve its net-zero goals but it is not without challenges. With careful planning and the right expertise, London could become one of the world’s first carbon-free metropolitan hubs, setting a benchmark for other cities to follow.