Feedbacks in district heating systems and transition policies: A systems analysis of net-zero district heating transitions in Europe

Net-zero district heating systems are considered a feasible heating alternative to replace individual natural gas boilers to mitigate emissions in European cities. However, achieving carbon-neutral cities in Europe is a complex affair due to interdependencies in energy transitions. Energy transitions are discussed as products of interdependencies between socio-technical elements within each context, including but not limited to institutions, society, culture, markets, policies, regulations, and technological disruptions/changes. These interdependencies have the potential to transcend beyond the boundaries of technologies, sectors, markets, policies, cities, and even countries which may result in feedback effects. The presence of feedback effects implies co-evolution: policy-making shapes energy system developments which, in turn, influences policy-making through a range of feedback effects. The objective of this study is to increase knowledge on the implications of feedback effects in energy systems and transition policies by highlighting how they can lead to unexpected systemic consequences, thereby causing inertia or acceleration during the switch out of individual natural gas boilers towards net-zero district heating systems. Understanding the root causes and mechanisms behind district heating transitions could support European policymakers in developing policies that can stimulate the transition toward carbon-neutral cities. Our results implicate that energy transition governance seldom consists of “simple” fixes as often claimed by popular policymakers or influential actors because each decision impacts the whole system. Different policy sub-goals are indispensable for achieving carbon-neutral cities but they are often indirectly in conflict with each other due to feedback effects. Unless feedback effects in transitions are acknowledged by policymakers, they could work against carbon-neutrality targets due to wrong assumptions and prioritizations of inconsistent policy sub-goals. Therefore, it is essential for policymakers to recognize and comprehend how feedback effects between energy systems and policies are formed and operate.