Department of Environmental Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
Waste Manag. 2010 Jul;30(7):1264-72. doi: 10.1016/j.wasman.2010.03.026. Epub 2010 Apr 10.
Municipal solid waste incineration contributes with 20% of the heat supplied to the more than 400 district heating networks in Denmark. In evaluation of the environmental consequences of this heat production, the typical approach has been to assume that other (fossil) fuels could be saved on a 1:1 basis (e.g. 1GJ of waste heat delivered substitutes for 1GJ of coal-based heat). This paper investigates consequences of waste-based heat substitution in two specific Danish district heating networks and the energy-associated interactions between the plants connected to these networks. Despite almost equal electricity and heat efficiencies at the waste incinerators connected to the two district heating networks, the energy and CO(2) accounts showed significantly different results: waste incineration in one network caused a CO(2) saving of 48 kg CO(2)/GJ energy input while in the other network a load of 43 kg CO(2)/GJ. This was caused mainly by differences in operation mode and fuel types of the other heat producing plants attached to the networks. The paper clearly indicates that simple evaluations of waste-to-energy efficiencies at the incinerator are insufficient for assessing the consequences of heat substitution in district heating network systems. The paper also shows that using national averages for heat substitution will not provide a correct answer: local conditions need to be addressed thoroughly otherwise we may fail to assess correctly the heat recovery from waste incineration.
城市固体废物焚烧产生的热能占丹麦 400 多个区域供热网络热能供应的 20%。在评估这种热能生产的环境后果时，典型的方法是假设可以以 1:1 的比例节省其他（化石）燃料（例如，输送 1GJ 废热可替代 1GJ 基于煤炭的热能）。本文研究了在丹麦两个特定的区域供热网络中基于废物的热能替代的后果，以及连接到这些网络的工厂之间的能源相关相互作用。尽管连接到两个区域供热网络的废物焚烧厂的电能和热能效率几乎相等，但能源和 CO（2）账户显示出明显不同的结果：一个网络中的废物焚烧导致每输入 1GJ 能源可减少 48kgCO（2），而另一个网络则为 43kgCO（2）/GJ。这主要是由于连接到网络的其他热能生产厂的运行模式和燃料类型存在差异。本文清楚地表明，简单评估焚烧炉的能源效率不足以评估区域供热网络系统中热能替代的后果。本文还表明，使用国家平均热替代率将无法提供正确答案：需要彻底解决当地条件，否则我们可能无法正确评估废物焚烧的热能回收。
