Process heat: How chemical sites decarbonise

4 min read

Chemical sites need heat at different temperatures and often steam for production. Waste heat recovery, heat pumps and electric boilers can help replace fossil fuels. Hydrogen is an option for other applications where supply and infrastructure are suitable. The most economical combination depends on the site’s heat demand, energy prices and grid connection.

Map heat demand and waste heat at the site

What is industrial process heat? Process heat is heat used in production processes, for example for drying, distillation or chemical reactions. Planning must account for the required temperature as well as pressure, the amount of heat and how demand varies over time.

A heat inventory compares these requirements with available heat sources. These include exhaust gas streams and cooling circuits as well as potential users within and outside the plant. If heat supply and demand occur at different times, storage should also be considered.

The International Energy Agency identifies waste heat recovery and plant optimisation as ways to reduce fuel demand. Lower heat losses can also reduce the required size of a new electric heating system.

Companies are also subject to § 16 of Germany’s Energy Efficiency Act: they must avoid waste heat and reuse the waste heat produced insofar as this is possible and reasonable. The Act takes technical, economic and operational considerations into account and provides for exemptions, including for companies with an average annual total final energy consumption of no more than 2.5 gigawatt hours over the last three completed calendar years. More specific requirements may apply to certain installations requiring a permit.

Compare heat pumps and electric boilers

An industrial heat pump raises heat from a source to a higher temperature. Waste heat can serve as that source. Whether the system can supply the process depends on factors including the source temperature, the required flow temperature and the load profile.

Electric boilers can heat water or generate steam. At an existing site, companies need to assess how the new system will fit into the steam network and how much capacity the electricity connection can provide. An option analysis can also consider combining it with existing boilers or thermal storage.

The purchase price alone is insufficient for comparison. The calculation should include electricity supply, efficiency under expected operating conditions, maintenance, utilisation and any necessary grid modifications. The emissions balance also depends on how the electricity used is generated.

Assess hydrogen and infrastructure for each site

Hydrogen is another option for heat generation. Its suitability depends on the process and the available supply. The study commissioned by the German Environment Agency identifies in particular applications with high process temperatures or high plant throughput where electric alternatives had limited technical availability at the time of the study.

For an investment decision, companies should assess the origin of the hydrogen, its delivery price, the quantities required and the connection to supply infrastructure alongside the plant technology. The same assessment applies to electrification: a suitable grid connection and a reliable electricity procurement plan are part of the project.

Calculate the business case over the project’s lifetime

A robust decision compares the total costs of several options over their planned lifetimes. In addition to investment and financing, these include energy prices, operating hours, maintenance and connection costs. Scenarios with different electricity and gas prices show how sensitive the result is to changes.

Funding can affect the calculation. Companies must check which programmes and funding conditions are available for a project at the time of application. Climate protection contracts are aimed at eligible transformation projects in emissions-intensive industries and, under their funding guideline, take account of additional investment and operating costs compared with a reference installation.

For plant management, this suggests an order of assessment: first measure heat demand and waste heat, then calculate suitable technical options with the grid operator and plant engineering team. The site decides which measure to implement first based on economic viability, plant condition and security of supply.

Frequently asked questions

Image source: AI-generated (November 2026)

Translated from the German original using artificial intelligence. The German version is authoritative.