Energy efficiency for industries through synergies with urban areas

• Four towns and their possible energetic interaction with industries are modelled.
• Towns can utilize energy from industrial sources without the need of large storages.
• 3–35% of primary energy demand for the towns can be saved via industrial energy.
• Industrial energy use increases energy efficiency for both industries and towns.

Generally waste heat, waste water and waste streams are available as industrial energy resources in industrial plants and their roof areas for solar energy use. In Austria, until now, only waste heat has been used in small parts for heat supply of towns. The application of waste heat has so far been largely taken for internal heat recovery only. A holistic approach considering all available energy resources by the industry in synergetic connection with the surrounding urban areas is yet to feature. Only a few projects in terms of waste heat usage for district heating have been implemented. At international level, the utilization of industrial energy has also hardly been considered in a synergistic combination with the municipal authorities. Numerous legal requirements (Directive for Integrated Pollution Prevention and Control, law for energy efficiency) determine conditions for industrial companies in terms of their environmental performance and energy savings etc. To a large extent, the production processes are already optimized due to the application of quality management systems and other tools. With the help of other energy efficiency methods it is hardly possible to achieve the required energy efficiency savings without influencing the production process. Therefore, the energetic linking of industrial companies and urban areas through the usage of industrial energy, to cover the energy demand of the towns offers an energy efficiency measure for industries without biasing their economic behaviour. Additionally, this approach represents an opportunity for energy enhancing independency of specific regions. The potentials for synergies were examined based on four project regions in Austria with a population between 7000 and 12,000 inhabitants and a more or less strong penetration of industrial companies. It was found that in total, up to 35% of the total energy demand of the surveyed towns could be covered. This means also a saving of the primary energy demand for the towns in the same extent. For electricity, coverage of up to 46%, and for heat, coverage of up to 32%, are possible. That means that nearly no oversupply of the towns occurs and all accumulating industrial energy can be taken by the towns. The recovery and exploitation of the so far unemployed industrial energy leads to a significant increase of efficiency for the industrial companies.