Simulation analysis of value of energy storage technologies in existing energy systems

The desire to pursue decarbonisation of the energy sector has brought worldwide countries to face new challenges. The need of reducing CO\(_2\) emissions has discouraged the intensive use of fossil-fuelled generators, and the increasing share of electricity from renewable sources has urged the investment in new energy technology able to balance the variability of the generation. Of various technologies, energy storage provides a potential solution to the balance of energy networks, supporting the low carbon energy development. This work investigates the potential financial and environmental value of energy storage technologies when integrated into real energy systems. The results have been achieved through simulation analysis run on models that replicate the electricity dispatch of entire grid networks. Great Britain and Tenerife energy systems have been analysed as representative of two different electricity grid layouts, to assess the value of energy storage in different conditions. The simulation analysis focuses on various roles of the energy storage with the purpose to assess the most convenient operation for the investor or the overall energy system perspectives. When simulating Tenerife grid, the energy storage plays three different roles: acting as load-shifter to facilitate the regulation provision and minimise the costs, working in synergy with a single OCGT to improve its energy performance, or increasing the penetration of renewable energy when large wind power plants will be installed. From the energy system point of view, the best results are achieved when the storage increases the penetration of renewables, because the presence of the storage allows reaching the minimum system costs and CO\(_2\) emissions. In this case the operations of the energy storage device connected to the wind power plants save 0.5% of the total system costs, while the savings achieved with the similar device connected to the entire electric grid in absence of large renewable plants would be only 0.2%, and even less when directly linked to the single OCGT. It is interesting to notice that the case study that represents the most productive scenario for the entire energy system does not correspond to the most remunerative one for the energy storage owner. From the energy storage owner point of view, the best energy scenario is represented by the case where the storage acts as load-shifter, because it can maximise the number of discharge processes and profit from the fluctuation of the daily wholesale electricity price profile. One aim of this work is to examine how energy storage technologies can be operated to optimise the penetration of renewable electricity in existing energy systems. An interesting case study looks at the potential adoption of thermal storage devices in GB for converting wind electricity excess into heat for residential applications. The benefits achievable with this solution would not be limited to the power sector but they would be extended to the domestic heat demand because of the link created by the thermal storage. The savings of gas heating consumptions are directly reflected in the reduction of fuel costs, due to the decrease of natural gas used for space heating purposes. After the installation of 1.1GW of thermal storage devices in Scotland, the reduction of the wind curtailment would be almost 60% and it would correspond to the savings of 30% of the total gas heating generation that is needed for household consumption in Scotland. The simulation results have shown that when replacing the thermal storage capacity with electric storage devices or transmission enlargement the wind curtailment reduction would be almost negligible