‘Smart Power to Heat’: Hybrid Process Heating for the Metal Industry

Project Approach

In industrial melting processes such as hot-dip galvanizing, burner and furnace systems are already in use that can be operated with either natural gas or electricity.

ZINQ is now pursuing a new concept known as ‘Smart Power to Heat’ (SP2H), aimed at implementing bivalent process heat generation in the metal industry. The energy carrier coupling applied here enables systems in which both electricity and molecular energy sources (natural gas and/or hydrogen) can be used interchangeably and at 100% capacity. This allows for the grid-supportive use of renewable electricity, for example by switching to electric heating during surplus phases (e.g. when wind and solar generation is high), while using molecular fuels in regular operation. This approach – referred to as Smart Power 2 Heat (SP2H) – is technically implemented through so-called “thermal batteries.”

In contrast to monovalent flexibility (i.e. adjusting production volumes), this hybrid flexibility approach – the flexible choice of energy carrier – allows continuous operation without disrupting optimal production processes.

Continuously operated metal melting systems that primarily rely on gas (natural gas or, in future, green hydrogen) can, by investing in additional electric heating systems, utilize surplus electricity to generate the required process heat. Additionally, a certain amount of surplus electricity can be temporarily stored by overheating the molten metal (“superheat”) – creating a monodirectional thermal battery. A prerequisite for this bivalent energy system is the appropriate infrastructure: connections to both gas (hydrogen-ready) and electricity grids.

The application and benefits of the SP2H method – for both industrial users and the energy system – are examined in the study using the energy-intensive batch galvanizing industry as a practical example.

Project Objective

The project titled “Study on Grid-Compatible Process Heat Generation via Hybrid Heat Supply” aims to evaluate the feasibility, potential, and required framework conditions for using monodirectional thermal batteries as a specific form of power-to-heat energy carrier coupling (SP2H). The study will assess their grid-supportive role as a complement or alternative to bidirectional electricity storage systems, contributing to the optimization, stabilization, and flexibilization of the electricity grid in Germany, thereby enabling a cost-efficient and successful energy transition.

The project will assess the economic potential of the SP2H concept in comparison to conventional natural gas usage. In principle, the switch to electricity-based process heat is economically justified when electricity is cheaper than natural gas. This decision may be based on auction results for secondary balancing power/minute reserve services (under appropriate agreements with the transmission system operator), or on cost-saving opportunities in the electricity spot market (day-ahead or intraday). Currently, cost advantages over natural gas – and prospectively over green hydrogen – form the decision-making basis for selecting the energy source for process heat generation.

In addition to determining the technical and economic conditions for SP2H deployment in the hot-dip galvanizing sector, a key objective is to evaluate the transferability of the results to the broader natural gas-based process heat sector in Germany.

Project Partners

ZINQ Technologie GmbH
Project lead – plant operator – process expertise provider

Fraunhofer UMSICHT (subcontractor)
Techno-economic analysis and potential assessment of hybrid heat supply in hot-dip galvanizing

ESFORIN SE (subcontractor)
Marketing strategies – CO₂ reduction potential – market integration – operational strategies

ZVO (German Surface Technology Association)
Potential application partner