Development of an innovative business model for large-scale solar thermal plants for industrial and commercial companies

The current project has the aim to develop an innovative business model for large-scale solar thermal plants (> 500 m² collector area) for industrial and commercial companies. This business model offers the energy customer a contractually binding solution in a time frame of 3 to 5 years; also, the energy delivery costs are lower compared to conventional sources.

Short Description




This business model is going to be realized with an innovative approach, the so-called ‘mobile and flexible solar plant'. This means that the removable parts of the solar plant remain property of the investor. If required (e.g. if the customer makes modifications in his production line or moves to a different location), the removable parts of the plant can be detached, changed or re-used in a different building. The solar plant is financed in advance by an investor in an energy service model (ESM). The investor or operator of the plant reduces the operating risk by means of the re-utilizability of the plant. Additionally, the new model makes it easier to respond to changes in the customer's energy consumption, as the new system allows adding or removing collector area as required by the customer.

This flexible model makes solar thermal energy more attractive for companies in the industrial or commercial sector. This implicates an increased use of renewable energy and especially solar thermal energy in industrial and commercial businesses and in this way contributes to an effective reduction of the environmental pollution through emissions.

Overview over the project progress

  • First, the actual situation in the industrial and commercial sectors was investigated by a market analysis and by interviews with the industrial partners. Within the interviews, concrete technical and economical basic data were determined. Also, the attitude of the companies towards solar thermal engineering was perceived.
  • Based on the data received in the interviews, rough technical and economical concepts (case studies) were elaborated, leading to a first cost estimate for the mobile solar plant.
  • The case studies and the information of the interviews served for developing the business model.
  • Topics concerning possible subsidies and contractual aspects of the mobile solar plant were discussed.
  • Necessary technical adaptations of the solar plant and single components of it (e.g. the collector) were carried out in order to make the assembly and disassembly of the solar plant an easier task.

Outcome of the project

  • The industrial and commercial sectors have huge thermal energy needs and there is generally a lot of interest towards the use of solar thermal energy.
  • The current project provided a technical basis for an economically feasible concept of an easily removable solar plant.
  • Most decision-makers of industrial companies are currently ill-informed about the opportunities and the state-of-the-art of solar thermal engineering.
  • On the part of the customers, there is a high interest of realizing solar plants by an ESM (energy service model), i.e. the companies do not need make any financial investment.
  • Due to the very large energy needs that most industrial businesses have, the solar plants usually are large-area plants (500 up to many 1,000 m² solar collectors).
  • Large-scale solar plants are on a competitive basis compared to fossil fuels, and they have the additional advantage that the energy costs of a customer can be calculated up to 20...25 years in advance. The energy prices that solar energy can offer at present are in the range of the fossil fuel prices, and in some case they are even lower!
  • For the first time, it is possible to detach a large-scale solar plant if necessary, to carry it to a different location and to re-mount it on that location.
  • Industrial customers typically have energy needs that vary over the time. By means of an easily mountable and removable system for solar plants, it is now possible to respond to the changes in the energy needs - e.g. by mounting more solar collectors.
  • There is a possibility to get an investment subsidy for the solar plant.
  • Different investors could be found for the further realization of solar plants.
  • From a legal point of view it is possible that the solar plant remains property of the operator although it is firmly mounted on the roof of an industrial business.
  • The investment and the economic profitability of the solar plants depend largely from the plant size. The larger the solar plant, the smaller the specific costs of the plant (in € per m² of collector area). The specific investment cost of the solar plants also depend on the kind of application (e.g. domestic hot water preparation, space heating, space / process cooling,...); they are currently in the range of 270...460 €/m².

Project Partners

Project management

DI Horst Strießnig
S.O.L.I.D. Gesellschaft für Solarinstallation und Design mbH

Project and cooperation partners

  • TU - Graz, Institut für Wärmetechnik (Werkvertragspartner)
  • Mag. Diethard Isepp, Steuerberater (Werkvertragspartner)
  • Mag. Sebastian Eger, Unternehmensberater (Werkvertragspartner)
  • Dr. Josef Unterweger, Rechtsanwalt (Werkvertragspartner)
  • nahwä (Finanzierungspartner)

Contact Address

DI Horst Strießnig
S.O.L.I.D. Gesellschaft für Solarinstallation und Design mbH
Herrgottwiesgasse 188, A-8055 Graz
Tel: +43 (316) 292840
Fax: +43 (316) 292840-28