IW3: beacon project of the energy transition

As part of the BMWK-funded Energy Transition Laboratory IW3, Hamburg Institut is setting up the first Guarantees of Origin registry for green district heating in Germany. Heating Guarantees of Origin (GOs) make it possible to allocate green heat quantities to individual buildings and neighbourhoods. In the future, marketing green district heating as a distinct product could help to improve the economic viability of projects for district heating generation from renewable energies and waste heat.

About the IW3 Project

The name IW³ stands for “Integrierte WärmeWende Wilhelmsburg”. The aim of the project is to establish a climate-friendly decentralised heating supply for the residential quarters on Hamburg’s Elbe island that is CO₂-neutral and can manage without fossil fuels in the long term.

IW³ is one of the “Reallabore der Energiewende” (Energy Transition Laboratories). With this programme, the German Federal Ministry for Economic Affairs and Climate Action (BMWK) promotes the implementation of innovation projects on an industrial scale in order to accelerate the transfer of technologies and solutions for the energy transition to the market. IW3 is being implemented under the leadership of Hamburger Energiewerke, supported by a consortium of various partners, including Hamburg Institut Research gGmbH (HIR).

The core elements of the energy transition laboratory are the construction of a geothermal plant (IWU ) and an aquifer storage facility as well as research on the system integration of different heat sources (IWS ) and on novel trading and marketing mechanisms for climate-friendly district heating (IWM ).

Our “Green District Heating” sub-project

In the IW3 project “Integrated Heating Market” (IWM ), Hamburg Institut is implementing the sub-project “Green District Heating”. As a pilot project for Germany, a Guarantees of Origin registry for green district heating is being developed with the aim of making it possible to allocate green heat quantities to individual buildings and neighbourhoods. Building on experiences with the certified green electricity market, producers and heating suppliers will be able to market green district heating as a distinct product in a legally secure manner. Revenues from this can facilitate the refinancing of new projects for the generation of renewable district heating and thus create additional decarbonisation incentives.

Registry for green district heating online

The first guarantees of origin registry for green district heating in Germany went online at the end of May 2022 on www.waermeregister.de. Participation in the pilot registry is possible for heat suppliers and heat generators located in the project region of Hamburg.

The technical implementation of the registry was carried out in cooperation with Grexel. The first the first heating guarantee of origin for the Hamburger Energiewerke will be issued soon.


  • Analysis of the energy economic, regulatory and technical framework conditions for the introduction of Guarantees of Origin in the heating market
  • Exchange with stakeholders to deepen insights on the needs of different market participants on the supply and consumption sides
  • Implementation of a software-based Guarantees of Origin registry for green district heating which enables legally compliant verification of the green credentials of marketed heat quantities
  • Systematic evaluation of experiences from the use and operation of the registry
  • Investigation of regulatory development options for a building-specific determination of the primary energy factors of district heating supply, in order to increase the value of district heating from renewable energy and unavoidable waste heat sources

Links & Docs

At a European webinar on 9 December 2021, registry operators gained insights into the design of the IW3 green district heating GO registry. The presentations are available for download here:

An overview of central processes in the IW3 pilot registry (in German) is available for download here.

Project report “Guarantees of Origin for Green District Heating: Legal Framework and Design Options (August 2023)

More information on IW3 on the project website

Contact for further information:

Marina Kemper


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