Borderstep

Potentials and limits of district heating networks, with special regard to renewable heat sources

Examining networks of district heat utilities, in consideration of long-term heat storage in rural areas

District heating is still uncommon and used predominantly in urban communities. At present, the heat source is usually a single cogenerated small or medium power station. There is a certain deficit of theoretical knowledge as well as practical experience regarding more complex district heating networks with various energy sources and recipients (e.g. for thermal heating, industrial water treatment, cooling or process heat). Moreover, the intermittent nature of power requirements makes thermal energy reservoirs or peak load boilers necessary.

In addition to cogeneration (combined heat and power, CHP), other sources of low-temperature heat will also become more relevant to the emerging energy supply system of the future. The use of solar collectors leads to large amounts of excess heat in summer, and the scale of geothermal energy also makes an efficient use of heating networks necessary.

A study commissioned by the Federal Environment Agency (UBA) of Germany reckons that by 2050, about two thirds of heat required will be distributed in networks. In the short to middle term, heat input from CHP will still be the dominant source.

This research project aims at examining how best to connect conventional and renewable heat sources technically and economically.

In order to understand the control engineering and hydraulic properties of district heating networks, an analysis of the entire system - from production and transport to consumption and long-term storage – is essential. This includes dynamic simulations of the networks’ temperature and pressure properties, and of supplier and customer characteristics depending on time and location.

On manufacturer side, due to the existing market penetration, combined heat and power (CHP) plants and boilers with various renewable and fossil fuels will be examined first. On consumer side, air conditioning and process cooling (e.g., absorption refrigeration) will be considered as well as heating and industrial process heat production.

The Borderstep Institute will determine the regional, technological and economic development potentials of CHP, commercial and private heat recovery, solar water heating and geothermal energy for two model regions, as well as the availability of heating grids.

Heating, cooling and air conditioning demands for industrial, commercial and private buildings are estimated for these regions. This is the foundation for developing market scenarios and market potential assessments for the national market.

Guided interviews will be conducted with owners and operators of CHP plants, solar water heating systems, heat surplus storage systems as well as potential heat and cooling purchasers and investors. Technological and economic frameworks and the demands of integrating heat into the utilities networks will be the main focus of the questionnaire. Additionally, we will be examining socio-psychological obstacles and concerns such as the perception of energy supply security. The results of the market analysis and surveys will be presented to the appropriate target audiences and published as part of the entire project coverage.

Project duration:
March 2010 to February 2013

Project partners:
Borderstep Institute
University of Applied Sciences and Arts Hannover
Leibniz Universität Hannover
Technische Universität Braunschweig
District Heating Research Institute Hannover (FFI)

Funded by:
Ministry for Science and Culture of Lower Saxony (MWK)
EFRE

Contact person:
Dr. Jens Clausen
clausen@borderstep.de

Publications:
Clausen, J. (2012) Kosten und Marktpotenziale ländlicher Wärmenetze. (Arbeitspapier zu AP 6 A im Rahmen des Projektes). Hannover. free download

Clausen, J.; Winter, W. (2012). Die zukünftige Entwicklung von Nahwärmenetzen in ländlich strukturierten Gebieten. (Bericht zu AP 6 B im Rahmen des Projektes). Berlin, Hannover. free download

Clausen, J.; Winter, W. & Kettemann, C. (2012). Akzeptanz von Nahwärmenetzen. (Teilbericht zu AP 7 im Rahmen des Projektes). Berlin, Hannover. free download