The SimREN (Simulation of Renewable Energy Networks) software designs “close to reality” models of energy supply and demand systems following a “bottom-up” approach [1]. It was developed in 1999 by the Institute for Sustainable Solutions and Innovations (iSUSI) [2]. However, he model is not sold to third parties, but it is possible to pay for projects to be completed, with price varying considerably depending on the project.

SimREN uses independent and detailed models for energy demand, energy management, adapted distribution systems and energy supply can be used to study different energy systems relying on renewable sources. A national or island energy-system can be divided into N regions, each region subdivided in up to M sub-regions, each consisting of many different suppliers and consumers. The simulation uses real measured weather data for a complete year with a typical time resolution of 15 minutes for one simulation step (smaller and bigger steps can be chosen). Both supply and demand can be simulated with their dependence from the actual time and weather. All thermal generation and renewables can be simulated using the model except for wave and tidal power. Pumped-hydroelectric energy-storage, battery energy-storage, and hydrogen production can also be modelled but no transport technologies are considered. A detailed overview of the model is available in [3].

SimREN has been used to simulate a 100% renewable-energy electricity-sector for the region of Catalonia in Spain [4], and also a 100% renewable energy-system for Japan [3].


  1. Energy Rich Japan, Institute for Sustainable Solutions and Innovations, 4th July 2009,
  2. Welcome to ISuSI, Institute for Sustainable Solutions and Innovations, 4th July 2009,
  3. Lehmann, H., Kruska, M., Ichiro, D., Ohbayashi, M., Takase, K., Tetsunari, I., Evans, G., Herbergs, S., Mallon, K., S., P. & Aßman, D. Energy Rich Japan: Full Report. Institute for Sustainable Solutions and Innovations, 2003,
  4. Peter, S., Doleschek, A., Lehmann, H., Mirales, J., Puig, J., Corominas, J. & Garcia, M. A Pathway to a 100% Renewable Energy System for Catalonia. Institute of Sustainable Solutions and Innovations, 2007,