Increasing operational flexibility of integrated energy systems by introducing power to hydrogen

Abstract

Owing to the limited operating regions of combined heat and power (CHP) units, the operation of integrated energy systems suffers from low flexibility, low-cost efficiency, renewable curtailment etc. Meanwhile, as the capacity of renewable energies keeps growing and integrating into power systems, various methods, such as installing electric boilers to enable electricity-heat conversion, have been developed to absorb excessive renewables and increase system operation flexibility. To further increase the system operation flexibility, this study explores the possibilities of utilising electrolysers and hydrogen storage tanks to enable electricity-hydrogen-heat conversion. To better visualise the enhanced flexibility, this study presents extra flexibilities from electric boilers, electrolysers and hydrogen tanks as the equivalent operating region expansion for CHP units. In this study, the system is modelled as a mixed-integer optimisation problem which balances the electricity, heat and hydrogen demands in a 24-hour period. A 6-bus test system is used in the case studies to illustrate the effectiveness of implementing electrolysers and hydrogen storage tanks. The optimisation results show the application of hydrogen energy improves the system operation flexibility, reduces wind curtailment, thereby decreasing fuel consumption and carbon emission. Pr i, t pressure of unit i ∈ ℋS at time t (bar). c i, t cost of unit i ∈ CℋP at time t

Economic operation of integrated energy systems considering combined production of hydrogen and medical oxygen

“…The uncertainty of renewables raises natural concerns of maintaining the real-time balance between energy demand and supply, along with reducing the curtailment of renewables. As integrated energy systems (IESs) include various devices and couples heating and electricity systems, they can help improve the operating flexibility of energy systems [2,3]. Thus, developing IES has been considered a feasible pathway to reliable and economic renewable-powered energy systems [4,5].…”

“…In recent years, the power-to-hydrogen (P2H) is recognised as a promising method to enhance the economics of IES further, and help reduces renewable curtailments [3]. Because hydrogen can generate heat and electricity, produce methane, and power fuel cell vehicles [6].…”

“…Because hydrogen can generate heat and electricity, produce methane, and power fuel cell vehicles [6]. Currently, excess renewable energy is recognised as a suitable energy source for P2H [7], and researchers usually use mixed-integer models to evaluate the economics of this measure [3]. In practice, P2H in IES is realised by electrolysing water.…”

Modelling and control coordination scheme of a wind‐to‐hydrogen set for future renewable‐based power systems

“…ELZs have the potential to participate in the provision of primary service [4] and perform faster in frequency support than conventional generators [5]. In [6], it is shown that utilising ELZs can increase the operational flexibility of an integrated energy system consisting of combined heat and power and wind power. Also, a set of an ELZ and FC can be integrated into a stand-alone microhydro plant or a microgrid to provide long-term energy balance [7,8].…”

Linear network model for integrated power and gas distribution systems with bidirectional energy conversion

“…The produced hydrogen or hydrocarbons can be stored in gas storage tanks or injected into the natural gas network, for which the surplus RDG can be spatially or temporally shifted [34,35]. Due to the compressibility of gas, more flexibility can be exploited to improve operational efficiency [36]. In the inner processes of P2G stations, it is the first step that the alternating current is converted to the direct current which is used for electrolysis.…”