Beyond electrification Worldwide, process industries rely heavily on natural gas and oil to generate process heat. These industries include food production, chemicals, pharmaceuticals, and other manufacturing sectors where a reliable heat supply is essential for daily operations. Reducing emissions from these sectors is often more complex than decarbonising buildings or electricity generation. Industrial processes require stable energy supplies, competitive costs, proven technologies, and an understanding of linked subprocesses. Many companies therefore focus primarily on electrification – or simply postpone addressing the issue. However, electrification is not always the most practical or cost-effective solution. In some cases, it may not even be feasible due to limitations in the local power grid. Alternative approaches are needed to accelerate emission reductions while maintaining industrial competitiveness – here DH can play a significant role. This is demonstrated by cases in operation in Europe and practical experience from Artelia’s work as a technical consultant to both industry and DH. The next step is to move from pioneering cases to a standardised methodology to support better decisions. Two current answers When an industrial company starts planning for solutions to become more sustainable, two solutions usually come up first. The first is electrification. Fossil-fuel boilers are replaced with heat pumps or electric boilers, installed on site. The company provides its own heat supply, powered by electricity. The second approach is to continue using fossil fuel locally but recover the surplus heat instead of wasting it. The surplus heat can be applied either internally or supplied to external users. This is typically low-temperature heat, but a heat pump can upgrade it to a suitable temperature level, allowing it, for example, to be utilised in a DH network to heat buildings in the surrounding urban area. New answers emerging Both approaches require the company to organise and implement the solution largely on its own. That is already an obstacle, but there are other major concerns too. For electrification, the uncertainty is future electricity prices, connection costs, and security of supply. For surplus heat recovery, the underlying problem remains if fossil fuels are still being burned on site. A third option is emerging, though still rarely seen in practice: a tailor-made mix of technologies and energy carriers, combining electricity, DH, and sometimes other solutions, matched to what each company needs. The Hot|Cool article “District Heating brings value to the process industry” lists benefits for both sides and gives examples of cases in operation across five countries. Instead of solving the challenge alone, the company can draw on the energy infrastructure already around it, such as the power grid and a DH grid. DH can supply heat to the
company, not only receive it. It becomes part of a flexible, tailored solution for that specific site. The available DH supply may not always meet the required temperature levels at a given site. However, several technologies can be applied to increase the temperature to the desired level. Although this requires additional equipment and investment, it can still be economically attractive in many cases. DH also brings something else to the table: a track record. Many DH utilities have steadily reduced the carbon content of their heat supply for years, and have a demonstrated record of continuous supply, with a low risk of failure — a quality highly valued by industrial customers. Broaden the perspective to see new solutions This is relevant for companies located near an existing DH network. But it is just as relevant when a DH system is being planned — in that case, industrial heat supply and demand should be designed into the network from the very start. Electrification and reuse of surplus heat remain valuable solutions, but they should not always be seen as the only options. In some cases, they can stand on their own; in others, they can form part of a tailor-made energy mix for industrial companies or areas. The shift in mindset is toward combined solutions that improve affordability and flexibility — and toward remembering that DH could be a key component of that mix. Seeing the whole picture An industrial production line rarely needs just one type of energy. It needs heat and electricity, at different times of the day, at different temperatures, across many connected sub- processes.
INVERTER
SOLAR CELLS (PV)
ELECTRICITY DEMAND
HEAT PUMP
ELECTRICITY GRID
HEAT DEMAND (WATER)
GAS BOILER
HEAT (WATER)
SPACE HEATING
GAS GRID
NATURAL GAS
GAS STEAM BOILER
HEAT DEMAND (STEAM)
HEAT (STEAM)
ELECTRICITY STEAM BOILER
ELECTRICITY
NATURAL GAS
ELECTRICITY
HEAT (STEAM)
SOLAR ENERGY
HEAT (WATER)
Figure 1: An example model of an industrial site’s energy system — the reference case before any integration with a DH system. Solar power, the electricity grid, and the gas grid feed a heat pump and boilers, which supply the site’s electricity demand and its water- and steam-based heat demand. The same type of model can then test alternative setups, including how district heating could supply part of this heat.
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