Energy  |  Successes  |  30.08.2011

Systematic Implementation of Small Scale CHP-Plants

The Frankfurt City Council decided in 1990 that distributed co-generation should become a major part of the City’s climate protection programme. Following resolutions of the City Council, the Energiereferat started to perform systematic studies on potential sites for distributed co-generation systems in 1990. For the project a consistent method for evaluating the technical feasibility and economic viability was developed. The studies also covered the environmental impact of co- and, in some cases, tri-generation.

Thirteen sites with a high heat and power demand (hospitals, public swimming pools, offices) were selected for feasibility studies. In the beginning only sites outside the district heating service areas were investigated in order to avoid competition between district heating and co-generation. The focus of these studies was on technical viability, taking into account neither the state of the installed heating system nor the readiness of the building-operator to invest in a “new” technology. As a result, only one project in a hospital was carried out as an immediate outcome of these studies in 1994. With an annual operating time of over 8,200 hours in the first year of operation, this tri-generation project in a hospital was very successful.

In the light of these studies, sites for further studies were selected taking into account economic and emotional aspects in addition to technical criteria. Further studies were also carried out for particular applications, e.g. old people’s homes, hostels and workshops for the handicapped.

To date more than 250 feasibility studies have been prepared for hospitals, office buildings, old people’s homes and other areas with high heat and/or electricity consumption. In addition to feasibility studies for new or existing buildings, the Energiereferat is preparing case studies on energy supply alternatives for new urban development schemes.

This process has been given the title systematic discovery planning. As a result of this process distributed CHP generation in small and medium sized units in the city was increased. In total 150 CHP plants have been installed until now with sizes ranging from 5 kWel (kindergarten) to 4000 kWel (German Federal bank).

The surveys carried out in Frankfurt show that there is a further potential for distributed small and medium size co-generation units of at least 20 to 30 MW. The co-generation plants are financed and operated either by the owner of the building itself or by contracting companies (e.g. local utility, private contractors, building departments). Most of the plants are powered by natural gas, which allows CO2 and NOx emissions to be reduced to a level 50% below the legal requirements. Fuel oil is also used in some of the plants. The first co-generation plant (440 kWel) using biogas from a composting plant started operation in 1999. With a new German law (EEG), rates for electricity from renewable energy have been fixed at satisfactory levels so that in the future co-generation plant using renewables (biogas or bio-fuel) might become more frequent. The wide range of application areas, i.e. hospitals, schools, offices, small residential district heating systems, private houses, swimming pools, a botanic garden and hostels, demonstrate that co-generation is not only limited to industry.

An article from, where you can read extensively about the role of the Greens in this process.

Back to Overview commons Javier de Jaureguiberry