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New study shows in detail for the first time how the heat transition can work in industry

What does the future of heat generation in industry look like? A new study by Fraunhofer ISI and the IOB at RWTH Aachen University now looks in detail at the other half of the heat transition for the first time and provides an overview of the state of the art of climate-neutral alternatives. The challenges are complex, as they involve plants in continuous operation, temperatures that often exceed 1,000 degrees Celsius and very high energy densities. The study commissioned by the Federal Environment Agency shows where alternatives such as hydrogen or electrification could become established and which challenges must first be solved by the state and companies.

The new study by the Fraunhofer Institute for Systems and Innovation Research ISI and the Institute for Industrial Furnace Construction and Heating Technology (IOB) at RWTH Aachen University provides the first systematically broad overall picture of the technical possibilities and challenges of switching to CO2-neutral process heat in the industrial sector. A total of 13 sectors with 34 applications in the metal and mineral industry were analysed at a level of detail not previously presented. The applications analysed are representative of around 1,800 individual process heat plants in Germany.

The study analyses the current state of the art and future potential of the various CO2-neutral alternative technologies, taking into account technical, economic and ecological criteria. Electrification and the use of hydrogen were considered in particular as possible alternative technologies for the conversion of plants and processes.

Climate-neutral process heat generation is technically feasible by 2045

A large proportion of greenhouse gas emissions in the industrial sector are caused directly by process heat. The study shows that the switch to climate-neutral process heat generation by 2045 is technically feasible in principle. CO2-neutral alternatives are available or under development for all applications. The opportunities, challenges and technological maturity vary greatly between sectors. A transformation strategy towards CO2-neutral process heat must take these structural differences into account and at the same time set a clear goal of greenhouse gas neutrality.

Electrification vs. hydrogen - the answer differs depending on the industry

The use of hydrogen can be advantageous over electricity, particularly in gas-fired industrial processes that require a very high energy density. Here, direct electrification is often not yet technically mature or requires significant modifications to existing systems. The complete electrification of industrial furnaces still faces major technical challenges, for example in the minerals and steel industries. Although electrical systems are already being used in isolated cases, electrification in existing systems is usually much more complex than the use of hydrogen.

According to the study, applications with comparatively low temperatures or low production capacities should rather rely on electrification, which is often already available on the market. Which solution is advantageous also often depends on the location - for example, due to the hydrogen infrastructure planned in the vicinity or the expansion of the electrical connected load.

Electric vapour generation already available on the market

When looking at the maturity levels of the various technologies, the report shows that steam boilers using electricity or hydrogen are already available on the market on an industrial scale, particularly for steam generation. More energy-efficient than these electric steam boilers are, for example, large heat pumps that are already available in the paper and food industries, which can generate the temperatures required for steam generation in an even more energy-efficient manner.

A direct entry into the transformation of steam generation is possible via hybrid systems, i.e. the short-term retrofitting of existing gas-fired systems with electric heat pumps or steam boilers. These can then be operated flexibly in times of low electricity prices and allow a low-risk entry into the transformation.

Further research, development and demonstration is needed

The use of hydrogen is not yet ready for the market in most applications; the technologies are still at the pilot and demonstration stage. However, the researchers assume that hydrogen heating technology can be operated in the near future in the form of industrial-scale systems and that it will often be possible to retrofit existing gas-fuelled furnaces. The greater uncertainty lies in the availability of green hydrogen at the respective industrial location.

According to the study, targeted research, development and demonstration are now required for both electrification and the use of hydrogen in industrial furnaces in order to make the technologies marketable and competitive. Technological development via pilot and demonstration plants as well as the large-scale industrial market launch should be specifically promoted.

The state must create a framework for economic operation

The study concludes that the current instrument framework is not sufficient to enable the transformation of process heat by 2045. Many industrial plants have long modernisation cycles and are sometimes used for several decades. At the same time, alternative technologies are not yet economically viable and uncertainties regarding the availability of green electricity or hydrogen at the respective location are very high.

The political roadmap for the transformation in the industrial sector must therefore create planning security for companies so that plants can be modernised or replaced as quickly as possible and, in particular, re-investment in new fossil fuel plants can be avoided - as these would be in operation until after 2045. Energy costs are crucial here: CO2-neutral hydrogen and electricity from renewable energies must be competitive with natural gas. Various instruments are possible to achieve this, such as a higher CO2 price to make fossil alternatives more expensive, a reform of grid fees to enable hybrid heat generation or targeted measures to reduce electricity prices for electrical process heat during the transformation phase.

Study author Dr Tobias Fleiter, Business Unit Manager in the Competence Centre Energy Technologies and Energy Systems at Fraunhofer ISI, concludes: "The decisions for the future of process heat in the various sectors of our industry must be made now. Our study shows what the opportunities are for the individual sectors. Which industry will and can rely on electrification? Where will climate-neutral hydrogen be used? Time is of the essence, as many industrial plants have an operating life of several decades. If our industry is to be climate-neutral by 2045, the framework for this must be created now."

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