Micro Cogeneration : towards a Decentralized and Sustainable German Energy System ?

Micro cogeneration – the simultaneous production of heat and power in an individual building based on small energy conversion units such as Stirling and reciprocating engines or fuel cells – is expected to increase energy efficiency on the level of household energy supply. A large-scale introduction of micro CHP may radically change the electricity system and turn consumers into power producers. At the same time, micro CHP could, if supported by favorable economic and policy conditions, represent a considerable market segment, promoting downstream innovations such as "virtual power plants", altered consumer awareness or new household energy management systems. This potential has to be evaluated with respect to its sustainability in both economic and ecological terms. In the paper, we present selected results of a case study of an interdisciplinary research team (Pehnt et al., 2006). The case study considers the status quo and potential of micro cogeneration in Germany. The diverse consequences of a broader introduction of micro CHP for the energy market, the customers, the environment and the economy require an interdisciplinary investigation into the real benefits and barriers of micro CHP. We use various methods, including a life cycle assessment of ecological impacts, a model of its economic performance, and an institutional economics analysis of actors involved in (potentially) implementing micro cogeneration on a larger scale. In the public perception, high expectations are associated with the introduction of technologies such as fuel cells, while other – more developed – CHP options, such as Stirling and reciprocating engines, are hardly known yet. Correspondingly, perceptions and expectations on the level of government, industry, and science will impact on the level of policy support and incentives granted to micro cogeneration. The paper will discuss the status quo and perspectives behind this observation.