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The electricity production from Renewable Energy (RE) in isolated locations requires long-term energy storage systems. To that end, Hybrid Energy Storage Systems (HESS), through a combination of hydrogen and batteries, can benefit from the different advantages of both technologies. This paper presents a hybrid Power-to-Power (PtP) Optimal Power Dispatch (OPD) model for isolated systems with no electric grid access. Currently, the electricity supply in such cases is usually based on a mix of RE as the primary energy source sustained by a diesel genset acting as a backup generator. In this context, the model delivers the hourly energy flows between renewable production sources, energy storage devices and the electrical load, which minimises costs and Green House Gases (GHG) emissions. For validation purposes, the model was tested through its application to a case study in an isolated area in the Canary Islands, Spain. The results show that the algorithm calculates the hourly OPD successfully for a given plant sizing, considering the defined operational states of the different assets. These operational constraints showed a decrease in the PtP round-trip efficiency of 5.4% and a reduction of the hydrogen production of 9.7%. Finally, the techno-economic analysis of the results proves that the combination of hydrogen and batteries with RE production is a feasible alternative to phasing out fossil fuels for the selected case study – reducing the diesel generator usage down to 1.2% of the yearly energy supply. • Novel multi-state optimal power dispatch model for power-to-power energy systems. • Multi-year techno-economic evaluation of an off-grid case study. • Phasing out fossil fuels with renewable energy-based hybrid energy storage systems. • Hydrogen technology contributes to a lower levelized cost of energy. • High initial investment cost was a significant entry barrier to deploying hydrogen. [ABSTRACT FROM AUTHOR]

This paper considers the case study of a smart microgrid district at Graciosa Island in the Canary Islands. The smart energy microgrid district consists of several households and a public use building (school) that includes renewable energy sources (photovoltaic), Li-ion batteries for electric energy storage, domestic hot water heaters acting as thermal energy storage, a pool for balancing energy consumption and supplies, and the connection to the electric grid. We have modelled such a problem as a nonlinear mathematical programming model that is linearly approximated using special ordered sets of type 2. The linear approximation is solved using Gurobi optimization software, providing close-to-optimum solutions within an interval of 15 min that allows near-real-time operation of the smart energy district. The obtained results allow advancement of the net-zero energy neighbourhood concept in all the evaluated scenarios within a daily horizon and a positive energy balance in wider horizons. Obviously, these results are obtained in part due to the magnificent insolation conditions of the Canary Islands, but they allow justifying that the appropriate use of renewable energy resources and energy storage systems together with a balancing mechanism at the district level (such as the pool in our case study) may also lead to near-net-zero energy neighbourhoods in other geographical locations. [ABSTRACT FROM AUTHOR]