This paper provides a systematic review of 34 large-scale projects of power-to-heat demand response. The projects have been classified in terms of location, size, technical implementation and objective. The chronological ordering of the reviewed projects enables key takeaways to be drawn considering other developments in the energy sector, such as its restructuring and the emergence of competing flexibility options. The presented approach provides renewed insight to the debate on power-to-heat demand response diffusion. Historically, power-to-heat demand response has been used because of its wide availability on the demand side. Within utility programs, it has mostly been used to deal with infrastructure capacity limitations. This is still a major driver for power-to-heat demand response today. To address the challenges that come with the integration of renewable energy sources, more recent research projects have focused on exploring its capability to provide real-time balancing and frequency response at a smaller scale. The literature review suggests that the period of energy sector restructuring introduced uncertainty to energy companies regarding power-to-heat demand response and thus influenced its use. This period is now superseded by developments focused on electricity markets that are open to the demand side. Considering the flexibility requirement of the future energy system, new opportunities arise for power-to-heat demand response. Based on a critical analysis of the technical and regulatory changes, this paper makes the claim that the economic and policy frameworks have had a much more significant effect on the varying diffusion of power-to-heat demand response than the effect of the control and information technologies. In that sense, market rules should be carefully tailored so as to unlock the flexibility not only of power-to-heat demand response, but also of other flexibility resources.

本文对34个大型的热电需求响应项目进行了系统的回顾。根据位置，规模，技术实施和目标对项目进行了分类。审查后的项目按时间顺序排列，可以根据能源行业的其他发展情况（例如能源行业的结构调整和竞争性灵活性选择的出现）得出关键要点。提出的方法为有关电力对热需求响应扩散的辩论提供了新的见解。从历史上看，由于在需求方具有广泛的可用性，因此一直使用电热需求响应。在实用程序中，它主要用于处理基础结构容量限制。如今，这仍然是电力对热需求响应的主要驱动力。为了应对可再生能源集成带来的挑战，最近的研究项目集中在探索其以较小规模提供实时平衡和频率响应的能力。文献综述表明，能源行业的重组时期给能源公司带来了不确定的动力-热需求响应，从而影响了其使用。现在，这一时期已被侧重于对需求方开放的电力市场的发展所取代。考虑到未来能源系统的灵活性要求，从电力到热力的需求响应将出现新的机会。根据对技术和法规变化的严格分析，本文认为，与控制和信息技术的影响相比，经济和政策框架对电热需求响应的变化扩散的影响要大得多。从这个意义上讲，应该仔细制定市场规则，以便不仅释放电力对热需求响应的灵活性，而且释放其他灵活性资源的灵活性。