SAPHyR

A large share of heat generation in district heating networks is currently still based on fossil fuels. The integration of waste heat plays a central role in the decarbonization of district heating networks. As of 2024, unavoidable waste heat already accounted for 14 percent (18 TWh) of the green share of district heating generation. Two sources of waste heat will be of great systemic importance in the future but have been scarcely researched to date: waste heat from hydrogen production and from data centers. Both sources offer the potential to reduce hydrogen production costs and make data center operations more economical—yet a system-wide assessment of their contribution to the heating transition is still lacking.

The SAPHyR project analyzes these two sources of waste heat from three perspectives: (1) systemic analyses using energy system models, (2) site-specific analyses using a heat network model, and (3) a legal analysis of the existing regulatory framework and barriers. To this end, the Enertile, DisCo, SPIDER, and DINO models developed by the project partners Fraunhofer ISI and EWI are coupled and expanded to include waste heat from electrolysers and data centers.

Project goals

• Quantification of the technical and economic potential of utilizing waste heat from electrolysers and data centers for district heating networks in Germany, as well as the impacts on the overall energy system
• Identification of suitable, system-friendly locations for electrolysers and data centers, taking into account the power grid, heating networks, and waste heat utilization
• Development of decision-making frameworks for policymakers, industry, and researchers to adapt the legal framework for improved waste heat utilization

Research Questions

• What is the technical, site-specific potential for utilizing waste heat from electrolysers and data centers in district heating networks in Germany?
• What are the systemic effects of this waste heat utilization on the overall energy system, particularly on the power grid and district heating supply?
• Under what conditions is waste heat utilization economically viable?
• How should the legal framework be adapted to ensure that waste heat is actually utilized in practice?

Role of EWI in SAPHyR

The EWI is collaborating on “Work Package 2—Systemic Analysis of Waste Heat from Electrolyzers and Data Centers” and is responsible for leading and carrying out the work on “Work Package 3—Site-Specific Analysis of Waste Heat from Electrolyzers and Data Centers.”

• Further development of EWI’s proprietary power grid model, SPIDER, to incorporate district heating potential and additional constraints (e.g., hydrogen and data networks), to identify locations for electrolyzers and data centers that are beneficial to the power grid while taking waste heat utilization into account
• Expansion of EWI’s proprietary district heating model, DINO, to include the endogenous operation of electrolysers and data centres, to determine cost-optimized hydrogen production and cost-optimized data centre operation while simultaneously utilizing waste heat
• Definition and analysis of up to four practical case studies of real district heating networks to examine the economic viability of waste heat utilization, considering different legal frameworks
• Provision of the scenario basis and comprehensive results as open-access datasets for use in further models and analyses