The Invert simulation tool supports the design of efficient promotion schemes for renewable and efficient energy technologies [1]. It was developed by the Energy Economics Group (EEG) at Vienna University of Technology in 2003 (with new features added constantly). Four major versions of the model have been released, and the current version can be downloaded from [1]. To date there is 170 users, and it takes approximately one day to learn how to use the software.

Invert is primarily used to simulate national energy-systems. The simulation can be run for up to a 25 year period, in 1 year time-steps and it accounts for all sectors of the energy system. All thermal generation except nuclear power, all renewable generation except wave and tidal, no storage and conversion technologies, and only biofuel transportation are simulated by the model. The model focuses specifically on the heat sector, by analysing the utilisation of heat pumps, solar thermal, conventional heating systems etc. As the core objective of Invert is to evaluate the effects of different promotion schemes, all costs including feed-in tariffs, subsidies, soft loans etc can be defined in the model. Outputs include costs, unit productions, fuel consumption, mix of energy carriers, energy demands, and installed capacities of units required.

Invert has been used previously to identify sustainable energy solutions for the town of Jordanów, Poland, the city of Vienna, Austria and , the regions of Baden Württemberg in Germany and Cornwall in the United Kingdom, the island of Crete, Greece, the entire country of Denmark: A full overview of these studies and their conclusions is available in [2] while detailed conclusions are available in [3, 4]. In addition, Invert has been used to identify policies to support renewable energy in the heat sector [5], and to analyse the influence of different promotion schemes on the penetration of renewables in the electricity sector for the island of Crete [6].


  1. Invert, Vienna University of Technology, 25th April 2009,
  2. Ragwitz, M., Brakhage, A., Kranzl, L., Stadler, M., Huber, H., Haas, R., Tsioliaridou, E., Pett, J., Gürtler, P., Joergensen, K., Figorski, A., Gula, A., Gula, E., Sliz, B. & Wyrwa, A. Final Report of Work Phase 6 of the project Invert. Vienna University of Technology, 2005,
  3. Stadler, M., Kranzl, L., Huber, C., Haas, R. & Tsioliaridou, E., Policy strategies and paths to promote sustainable energy systems–The dynamic Invert simulation tool. Energy Policy, 35(1), pp. 597-608, 2007.
  4. Kranzl, L., Stadler, M., Huber, C., Haas, R., Ragwitz, M., Brakhage, A., Gula, A. & Figorski, A., Deriving efficient policy portfolios promoting sustainable energy systems–Case studies applying Invert simulation tool.Renewable Energy, 31(15), pp. 2393-2410, 2006.
  5. Bürger, V., Klinski, S., Lehr, U., Leprich, U., Nast, M. & Ragwitz, M., Policies to support renewable energies in the heat market. Energy Policy, 36(8), pp. 3150-3159, 2008.
  6. Tsioliaridou, E., Bakos, G. C. & Stadler, M., A new energy planning methodology for the penetration of renewable energy technologies in electricity sector–application for the island of Crete. Energy Policy, 34(18), pp. 3757-3764, 2006.