EHDO is a free webtool that determines and optimizes the configuration of energy supply systems. The tool was developed by the Institute for Energy Efficient Buildings and Indoor Climate at RWTH Aachen University. The primary purpose of this tool is to support academic teaching in the master program Energy Engineering at RWTH Aachen University.

EHDO is a tool to find an optimal energy supply system from a large set of possible system configurations. The optimal system configuration is calculated by a mathematical optimization model. All model parameters can be changed by the user. This makes EHDO a very flexible and widely applicable tool. EHDO has been developed for academic teaching at RWTH Aachen University: Students learn how optimal configurations of energy supply systems with high renewable penetration look like, how energy storage are sized and how energy carrier like hydrogen can be employed in future energy systems in an optimal way.