PESI - Paradigm shift in urban energy systems through synergies with industry
Starting point / motivation
More than a third of the energy demand is caused by the producing sector in Austria. Because of that, this approach is chosen by the industry to save energy and thus reduce the impact on the environment.
Contents and Objectives
Industrial enterprises are not only characterized by a high energy input, but also by the production of energy e.g. in the form of waste heat, waste water and waste, or available land can be used for the recovery of renewable energy. As far as possible the use of this energy is already done inside the companies. The not internally used energy is, however, in principle available for external use. Instead of releasing this energy unused to the environment, it can be used in the nearby town or urban region. The city acts as a sponge and absorbs the excess energy of industrial companies. This also increases energy efficiency.
In the project, the electricity, cold and heat generation from industrial waste heat, industrial waste water, industrial waste and the energetic use of roof areas are considered. Furthermore potentials are elevated and synergies with the urban energy demand are determined. This is done for four cities in the Styrian Murtal: Zeltweg, Fohnsdorf, Knittelfeld and Judenburg.
The project has the following key objectives:
- Creation of a data base
- Creation of a simulation model for the representative integration of industrial energy in a town
- Analysis of economic and environmental issues
Initially, energy-intensive industries are identified in Styria and in Austria. Based on that, the selection of the industrial companies is made for the project regions. Both for the industry, as well as for the cities the necessary data is researched, collected and processed appropriately.
Then, an equations-based simulation model is created which represents the industry and the city. The simulation model has been designed in a way that it can be adapted to various sizes depending on the requirements. The simulation was performed for all four cities and the model was improved by means of evaluation loops.
Based on the results of the simulation and data research, the economic analysis was carried out according to VDI 2067. Based on different scenarios, various funding systems are involved in the analysis. The effects of price volatility and future developments are considered in a sensitivity analysis.
The ecological assessment, consisting of two parts: The quantitative evaluation considers the impact of the industrial energy use on CO2 emissions. The qualitative assessment analyzed not measurable environmental impacts through the use of industrial energy.
It was found that up to 32% of the total energy demand of the cities can be covered by industrial energy. This leads to a reduction of the maximum power for electricity and heat generation. In addition, almost the total amount of accumulated industrial energy can be integrated into the energy system of the city. Just a few hours a year and at low extent an oversupply of industrial energy occurs.
The use of industrial power is not economical without obtaining feed-in tariffs. The implementation of PV systems is connected with little effort. The electricity production costs are largely influenced by the cost of PV modules. The use of industrial heat is also economical without investment funding. The heat production costs are most influenced by the cost of electricity, which is needed for the operation of the district heating pumps and heat pumps.
Depending on the proportion of directly usable heat and heat, which is used via heat pumps, a decrease in CO2 emissions and primary energy is recordable. CO2 savings of up to 20% compared to the current supply can be registered.
The use of industrial energy leads to a significant increase in energy efficiency for the industrial enterprises, a reduction of CO2 emissions and primary energy, a reduction in the dependence on external energy suppliers and thus an increase in the security of supply.
Prospects / Suggestions for future research
In the course of the research project four characteristic cities were examined in terms of their potential synergy with the industry. Through small adaptations the developed model can be customized for other cities. A generalization about the level of synergy potential for cities of the same size is afflicted with uncertainties; this can be reduced by increasing the number of analyzed cities.
The studied regions are nearby. A merger between consumption and supply across the city's borders would provide an opportunity to increase synergies and reduce any oversupplies.
The short-term oversupply, resulting from electricity generation can be stored either in suitable storages or used for hybridization. There, the oversupply is not fed in the power grid, but used for heat generation (power2heat). A comparison of the two alternatives has to be done.
University of Applied Sciences JOANNEUM, Institut for Energy, Traffic and Environmental Management
DI Dr. Matthias Theißing
DI Josef Bärnthaler - Energieagentur Obersteiermark