Reduced version of the model DIETER

This is a much-reduced version of the model DIETER (Dispatch and Investment Evaluation Tool with Endogenous Renewables). It is used for the stylized graphical illustrations in Wolf-Peter Schill's Commentary "Electrical storage and the renewable energy transition". This model version is derived from the one used in the paper "On the economics of electrical storage for variable renewable energy sources", https://doi.org/10.1016/j.euroecorev.2018.07.004. Whenever you use this code, please refer to the Commentary and/or the sources listed under http://www.diw.de/dieter.