District heating and passive houses - Interfering strategies towards sustainable energy systems

Panel: Panel 2. Making buildings more energy efficient

Author:
Philipp Späth, IFZ – Inter-university research centre for technology, work and culture

Abstract

Today, 'district heating systems' (DHS) in many cases are the most energy efficient option to provide space heating in densely populated urban areas. Such grid based systems involve heavy investments though, which in the form of 'sunk costs' create a 'technological lock-in situation', often accompanied by 'institutional lock-in'. After the decision for such an infrastructure is taken, these path dependencies usually rule out the application of decentralised efficiency strategies (such as investments in state-of-the-art insulation of houses) for many decades. In the long run, this can lead to non-optimal energy systems.

This raises two questions: a) whether and how the negative long-term effects of lock-in on efficiency can be reduced and b) on what basis optimal decisions on energy systems (in the long run) can be taken.

Scenarios about the path dependencies and the long term developments in energy systems (e.g. improved supply options and shifts in demand) are prerequisite for decisions on the most sustainable energy options. Ideally, such scenarios also show ways to reduce the prohibitive effects of DHS on future efficiency strategies in the planning phase. Technical factors like increasing efficiency standards are important for an adequate dimensioning of the generation and grid capacity. But even more important are institutional trajectories. As this paper exemplifies, specific tariff structures translate the technological path dependencies into economical incentive structures. They often prevent individuals to invest in efficiency improvements such as passive house standards or solar water heating. Since such tariff structures are often subject to public decision making processes, knowledge of such effects is crucial for opinion makers which seek to promote sustainable energy systems.

As a case study, the decision making process about the heat supply for 'Vauban District' in Freiburg, Germany is described and analysed. Indications are derived, what kind of alternative policy making process could have resulted in an outcome, that the actors were actually aiming for: the most efficient energy system available.