Optimization-based integration of a metal hydride storage in a residential energy system – A techno-economic analysis

The increased use of electrified heating systems in residential buildings places additional demands on the power grid, alongside the growing load from, e.g., photovoltaic power. One solution to relieve the strain on the power grid could be to increase the energy autarky of residential buildings by increasing the consumption of self-generated electricity. Higher self-consumption requires an energy storage system that is capable of storing large amounts of electricity (seasonally). Metal hydride storage systems could be a technically feasible solution. Excess heat from the metal hydride storage tank could contribute to the heating system and further reduce electricity consumption. This study aims to investigate the extent to which a metal hydride storage system can be used in a single-family house to relieve stress on the power grid significantly. To investigate this novel approach, a design and operation optimization is performed to determine the most cost-effective system configuration at maximum autarky level. Compared to a reference case with no seasonal energy storage, the autarky level could be increased by integrating a metal hydride storage system by 27%-points to 79% resulting in a feed-in reduction of 35% into the superior power grid. In addition, grid electricity consumption can be reduced by up to 45%. However, such a system results in a 4.3-fold increase in total annual costs. Even with positive developments in the future (technological and economic), this factor can only be reduced to 2.5. Independent of the clear cost increase under current cost relations, the integration of metal hydride storage systems into a future home energy system is a technically viable option. • Integration of metal hydride storage in a single-family house to increase energy autarky. • Metal hydride storage enables higher use of self-generated electricity. • Autarky level can be increased to 79%. • Total annual costs are 4.3 times higher with maximum autarky. • 35% reduction in electricity feed-in at maximum autarky.