Advanced energy flexibility enhancement via the novel resources of wave energy converter reservoirs and electric storages for a hybrid wave-wind energy supported hotel energy system

Abstract

Renewable resources are fluctuating and uncontrollable. The susceptible and intermittent generation not only causes the mismatch between the demand and supply but also brings grid pressure. Therefore, several measures were conducted on a coastal building energy system to enhance energy flexibility. From the aspects of operational cost, net present value, peak-shaving, valley-filling, and on-site electrical energy matching/fraction, a series of non-renewable and hybrid wave-wind-based renewable energy cases were studied to investigate the impact of the flexibility enhancement measures. Based on a specific electricity pricing scheme considering the monthly maximum power and the on-peak/off-peak energy demand, first, utilised the battery as a flexibility source to adjust the grid's interactions. It showed superior peak shaving capability during the on-peak period reaching 100%. Second, the battery control after the load which was partially covered by hybrid wind–wave energy reduced about 1% of operational cost. Generally, the battery control helped in various aspects whereas diminished the net present value due to high investment. Third, using the inherently integrated reservoir of the overtopping wave energy converter, the flexibility of the seawater discharging control like a reservoir-type power plant was investigated. The novel reservoir control presented outstanding comprehensive performance and feasibility. It enhanced the energy matching by 10% and reduced the operational cost to 83.99% compared with the case without employing control, bringing an extra 40% increment of relative net present value.