The project in Tongchuan shows an annual CO2-saving potential of 38,823 ton per million m2 floor area. If the same result can be obtained in similar urban areas, along with the 2 to 3 times increase in the DH market, this transition can lead to between 326 and 650 million ton saved CO2. This assumes that an additional area of 8.4 or 16.8 billion m2 floor area is converted from individual fossil coal (41 %) and natural gas (59 %) boilers with low efficiency. In Tongchuan, the DH sources of excess heat from the industry, waste-water treatment plants and CHP plants are all regarded as fossil free. In comparison, the total Danish CO2-emission in 2018 was 38.1 million tons CO2 meaning that the expected increase of the Chinese DH system equals savings of 8 to 17 times the Danish 2018 CO2- emission annually. It is noted that this is only CO2-emissions and not total emissions as gases like methane and nitrous oxide (N2O) are excluded in the DHAT calculations due to insufficient data.
Natural gas, electricity, geothermal heat, biomass, solar energy, industrial waste heat, ultra-low emission coal (CHP) and nuclear energy are in China defined as sources for clean heating. The share of clean heating was 34 % in North China in 2016 according to the government and it is expected to reach 50 % in 2019 and 70 % in 2021 which will replace 150 million tons of coal. For biomass alone, it is expected that the heated area will increase by 2.1 billion m2 heated floor area. These impressive plans mean that 28 large urban areas in the North are expected to be converted to DH in just a few years and will increase DH in China dramatically. The specific urban areas are currently without DH but will receive financial support from the Chinese government to promote the transition. The plan does not include development of DH systems in any other urban areas without DH. Individual coal boilers and DH coal boilers have been the cause of a large share of the pollution in China. Therefore, the government has asked the provinces to replace these with natural gas boilers or with heat from combined heat and power plants (CHP). The problem is that natural gas for boilers is relatively expensive and not affordable for many customers. The simultaneous increase of renewable solar Photo Voltaic systems (PV) and wind turbines are causing less heat production at CHP plants. This decrease in available traditional DH source creates a need for new approaches to DH. New clean heat sources, energy conservation, energy planning, new technologies, incentives for flexibility (power market) and structural changes (e.g. metering and changed billing) are needed; and China has not yet found a way to get this done without central planning and subsidies to selected projects. Without a new approach, the continued expansion of DH in the long rung will not be viable. Since 2012, the Danish Climate Envelope, through the Ministry of Energy, Utilities and Climate, has financed energy and climate related programs in several countries including China for supporting the green transition. The partnership program is implemented through an integrated government- to-government cooperation approach, designed to provide mainly technical assistance in a peer-to-peer manner. As a part of this, the DEA, in cooperation with the Chinese National Development ReformCommission (NDRC) andNational Energy Conservation Center (NECC), has made a demonstration project in Tongchuan, North of Xi’an in the Shaanxi province. DEA has demonstrated that the use of DHAT introduces new opportunities for heat planning in China. DHAT is widely used in other bilateral partnership programs managed by the DEA and the Ministry of Foreign Affairs. The project in Tongchuan focuses on implementing DH systems in the city to replace individual solutions and shows the potential for establishing clean, renewable DH systems with a pay-back of 5 to 8 years. Investors hesitate and demand a 3 to 5 years pay-back, which makes it difficult to execute these beneficial projects. The project, though, highlights a large potential for implementing DH even in urban areas without available CHP capacity.
CAN IT BE PREDICTED HOW LARGE THE DISTRICT HEATING SECTOR WILL BE? Yes, the expansion of DH can be predicted and is expected to grow 2 to 3 times in size during the next 30 years. It is noted that these predictions could be improved by having access to better statistics based on metered heat consumption. In China, statistics regarding heat demand in buildings are limited. It is only known how much heat is produced and how much floor area is heated with DH. The heat loss is not known and can only be estimated since supplied heat to buildings is not measured. The DH supply price is set by the government as a monthly price per m2 heated area and is the same for everyone independent of the efficiency of the installations. DH is usually only supplied for space heating and not for hot tap water use. The supply season is usually 4 or 5 months, meaning that the system is closed down outside the winter heating season. The CHP plants are still running to produce electricity, but use cooling towers to remove excess heat instead. Example of “partly optimized energy solutions”: Solar collector for hot tap water placed beside cooling pump emitting heat from the same apartment at the same time. The building is supplied by district heating during the winter, but when the sun is not shining, electricity is used for hot water. Picture from Beijing
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