Distributed Control Applied to Multi-Energy Generation Portfolios

In 2004 the Power Systems and High Voltage Laboratories at ETH initiated the research project ”Vision of Future Energy Networks” (VoFEN), which applies a greenfield approach to the design of future energy systems. The main aspect of the project is the consideration of multiple energy carriers, i.e. the analysis is not restricted to electricity but also considers other energy carriers such as natural gas, hydrogen and district heating [1]. By exploiting synergies among various forms of energy, system improvements in terms of overall energy cost reduction, system emission reduction and increase of reliability of supply can be achieved. The couplings between the different energy infrastructures are taken into account with the novel concept of the Energy Hub, which is a generalization and extension of a network node including conversion, conditioning and storage of multiple energy carriers. Energy systems are built up by a certain number of Energy Hubs. Based on these concepts, further methods have been developed. One of them is the application of mean-variance portfolio theory to portfolios generating multiple energy carriers. Efficient multi-energy portfolios are determined considering a set of possible scenarios and technologies. Using this method, investments in multi-carrier energy systems can be planned taking into account relevant risk factors. The resulting technology mixes can be considered as Energy Hubs. A network of interconnected hubs forms a distributed power generation structure where each hub is controlled by its respective control agent. A distributed control scheme is applied in order to guarantee the energy supply of the whole system during operation. In order to arrange coordination between hubs, the distributed control scheme is extended and applied to the geographically distributed portfolios. Here, these two concepts, portfolio theory and distributed control, are applied to a system consisting of three hubs, interconnected by an electricity and natural gas network.