Sino-Danish Clean Heating Expert Panel Workshop 4: CETO-chapter on heating

On Tuesday the 6^th of December 2022, the Sino-Danish Clean Heating Expert Panel met online for its fourth workshop. The Danish Energy Agency, China Renewable Energy Engineering Institute, and experts from China and Denmark gathered alongside other international experts and had a dynamic discussion on the outline and potential contents of the heating chapter in the China Energy Transformation Outlook (CETO) developed by the China Energy Transformation Programme.

The agenda started with a brief throwback to the latest expert panel workshop on the heat roadmap process for China followed by a thorough introduction to CETO.

To kick off and guide the discussion advisors from the Danish Energy Agency gave a presentation on the CETO-chapter outline, which includes three sections: heat demand, heat infrastructure and distribution, and heat supply.

Background – transformation of the heating sector

DEA is developing a chapter regarding the transformation of China’s heating sector to be incorporated in the broader context of China Energy Transformation Outlook, which is jointly produced by the Energy Research Institute of Chinese Academy of Macroeconomic Research and the Danish Energy Agency. The aim is to describe the status and development of the heating sector as part of the energy modelling that acts as a foundation for CETO. Throughout the chapter, heating is highlighted as a key sector with an emphasis on that heating can support the further transformation of the power sector and energy system through increased efficiency, flexibility and diversification.

Heat demand

When considering the heat demand we normally look at different key factors, namely which buildings are included in the calculated heat demand, and how the building sector is expected to develop. Heat demand should be considered as part of the energy demand; therefore, efforts should be put into estimating how the demand develops over time. The guiding questions for the discussion on heat demand included the following:

• CETO describes the main drivers behind the development of the building stock in regard to building standards, new buildings, retrofitting existing buildings and industrial efficiency. Any reflections on drivers for growth in heat demands and floor area?
• The traditional accounting in CETO might not consider small district heating systems to the desired degree resulting in a large share of the heat demand being excluded. How do you see district heating existing in large and small cities respectively?
• Are there practical difficulties meaning that domestic hot water (DHW) could not be included as part of the heat demand?
• If process heat is not included, does it hinder the representation of district heating? What are the implications of only focusing on heating residential/service areas?

The experts mentioned that the general practice to assess the heat demand in China is to know the heated floor area and roughly calculate the expected demand based on the local climate zone. Domestic hot water is seldom combined with the central heating systems but the heating systems on the community level often supply both space heating and domestic hot water.

The experts pointed out that there is an important distinction between central district heating production and community-based district heating. Often the latter is not included in statistical data on heat consumption and thus there is a risk of a large share of the heat demand being excluded.

Heat infrastructure, distribution and heat supply

Transforming heat supply focuses on diversifying supply technologies and replacing fossil sources with efficient and renewable sources as part of a decarbonisation strategy. There are many benefits in utilizing heat production technologies to benefit other sectors, which again emphasises the importance of including heat modelling in overall energy analysis. The questions guiding the discussion on heat infrastructure, distribution and supply included:

• Addressing the different sizes (and ownership structures) of district heating systems, since larger systems are likely to have more potential for aspects like sector coupling, integrated energy systems etc.
• We are unlikely to be able to explore an expansion in district heating areas in the long term, in this round of the CETO analysis, is this something the experts feel we should consider in the future?
• Specifically for the Chinese energy system, geography, and pathway to 2030 and 2060, how do you see the role of different district heating technologies for China?
  • Excess heat (both conventional high-temperature excess heat sources and low-temperature sources)
  • Combined generation of heat and power (CHP)
  • Electrification through large-scale heat pumps (LSHPs)
  • Local renewable potentials (solar thermal, geothermal)
  • Role of thermal storage (short and long-term)
  • Role of heat-only boilers (HoB)
• We consider these technologies as very flexible technologies in a modern adaptable heating system in Denmark. How do you see this in a Chinese context? How do you ensure that flexibility and interaction with other sectors are ensured in the planning of new district heating systems?
• What have been the advantages of including heat modelling in energy modelling so far?

In addition to the topics above, the experts discussed the importance of defining the different heating demands and systems to be included and the need for good data and definitions. This included specifically the potential for industrial excess energy.

China’s current heating system is a high-temperature DH system with large community substations whereas the Danish heating system model entails low temperatures and building-level substations. This led to a discussion supporting the various designs to include domestic hot water distribution systems were discussed, from a supply perspective.

Finally, the importance of including thermal storage and sector coupling was mentioned.