**Preface to "Alternative Sources of Energy Modeling, Automation, Optimal Planning and Operation"**

This Special Issue entitled "Alternative Sources of Energy Modeling, Automation, Optimal Planning and Operation" was proposed in order to cover alternative/renewable sources of energy (ASE/RES) modeling and computer simulation, RES automation and more precisely solar thermal plants, photovoltaic (PV) plants, autonomous PV installations, wind energy plants, small hydro plants, modeling, automation, optimal planning and operation. Fuel cells, hydrogen, batteries, and energy storage technologies, modeling, automation, optimal planning and operation were also considered within the SI's main purposes. Biomass, biofuels, biogas, gasification, bioenergy in general, tidal systems, geothermal systems, waste to energy modeling, automation, optimal planning and operation were also of interest. Moreover, hybrid ASE/RES models, automation, optimization, smart micro grids integration as well as ASE/RES forecasting and optimal planning based on artificial neural networks, fuzzy logic, neuro-fuzzy methods, machine learning and artificial intelligence (AI) methods were welcomed. Finally, optimization methods as well as decision support systems (DSS) applied in ASE/RES optimal planning and/or optimal operation as well as to the RES plants reliable grid integration were considered.

> **George S. Stavrakakis** *Editor*
