Wind-hydrogen System Research Articles

Size optimization and economic analysis of a coupled wind-hydrogen system with curtailment decisions

In order to maximize the return on equity (ROE) of wind-hydrogen system investors, take full advantage of the wind power as well as smooth the wind power output of a wind farm, an optimal sizing model of a coupled wind-hydrogen system (CWHS) is established considering the requirements of wind power grid-connection technology. The fluctuating cost of wind power is calculated by an “equal-kWh following load” method and the chance-constrained programming is introduced to deal with the uncertainty generated by the wind power. The optimal capacity of each unit for a CWHS, including the wind power transmission project, electrolyser, compressor and so on, is acquired and the economic analysis is evaluated under comprehensive aspects, e.g. wind curtailment decisions, hydrogen prices, the correlations between wind power output and system load, and the fluctuation degrees of wind power generation. The simulation is established by the realistic historical data from a wind farm in Fujian, China. When the confidence level is 92%, the capacity of electrolysers increases with the increase of the hydrogen price when it is larger than the equivalent value 4.34 €/kg. In addition, the smaller the correlation between wind power output and load and the bigger the volatility index of wind power output, the less the smoothing benefit of the CWHS, where the smaller capacity of the transmission project and bigger capacities of electrolysers and compressors are required.

Control strategy of electrolyzer in a wind-hydrogen system considering the constraints of switching times

In order to improve the operational performance of alkaline electrolyzers powered by wind power, the influences of the fluctuating wind power on alkaline electrolyzers must be taken in accounts. In pursuing this goal, the influences of fluctuating wind power on both the hydrogen production and the self-safety of alkaline electrolyzer is discussed firstly. And a wind-hydrogen integrated energy system (WHIES) integrated supercapacitor is designed to smooth the fluctuation of wind power. In which, the fluctuation of wind power is divided into two kinds, instantaneous fluctuation and wide power fluctuation, the former is absorbed by supercapacitors, the latter is overcomed by adopting a modular adaptive control strategy to optimize the operation mode of alkaline electrolyzer. A simulation has been developed for a specific wind farm located in Northeast China. The simulation results show that under the condition of fluctuating wind power, the WHIES with the proposed control strategy can reduce the switching times of electrolyzers by 93.5% and increase hydrogen production by more than 44.18% when compared with other control strategies.

Optimizing unit capacities for a wind-hydrogen power system of clustered wind farms

Optimizing unit capacities for a wind-hydrogen power system of clustered wind farms

Optimal sizing of a grid-assisted wind-hydrogen system

Hydrogen obtained from water electrolysis in addition to being sustainable becomes commercially competitive when a high degree of purity is sought. Ideally such purity is achieved by keeping the electrolyzer on a constant and rated power. To satisfy this objective the assistance of the electric grid to deal with the variability of the wind resource was proposed. The disadvantage of this alternative is the failure to ensure a 100% carbon-emission-free hydrogen. The surplus wind energy can be delivered to the grid to optimize the trade-off between purity and cleaning degree. This paper presents a study on how the electrolyzer should be sized – according to the turbine and wind resource – to fully compensate these emissions along the year, that is, to cancel the annual power supplied by the grid.

Feasibility of a Wind-Hydrogen Energy System Based on Wind Characteristics for Chabahar, Iran

Abstract The knowledge of wind speed characteristics of a region is among the most important aspect of wind turbines utilization for electricity production and assessing the cost of power generation. The wind spectrum and the wind power density for the city of Chabahar located in the southeastern part of Iran were modeled using Weibull distribution and power law estimation. An empirical approach was used to determine the shape parameter, k, and the scale parameter, c, of Weibull distribution function at different heights from 2014 to 2016 during two years period. Wind characteristics in Chabahar were extensively analyzed along with assessing the effects of parameters such as air humidity and temperature, surface roughness, turbulence, and wind velocity durations. The amount of wind power that can be produced by installation of eight wind turbines with different powers ranging from 2.5 kW to 8 MW at Chabahar were investigated. Additionally, the annual capacity factor for each turbine was determined. A wind-hydrogen system was considered in the analysis for evaluating the hydrogen production ability from wind energy in the station at Chabahar. The highest amount of hydrogen production was related to Vestas V164 with the yearly value of 194.36 ton-H2.

Influence of noise of wind speed data on a wind-hydrogen system

In recent years, the importance of greenhouse gas pollution has become a global issue. Due to environmental concerns over fossil fuels, most countries are considering renewable energies as an alternative for these traditional fuels, in order to prevent environmental damages. However, lack of year-round access to renewable resources is problematic. Nevertheless, the storage of electricity generated from these resources in the form of gas or liquid is the most sensible solution. In this study, a wind-hydrogen energy conversion system is proposed to produce hydrogen from wind energy, wherein the hydrogen production is proportional to the wind turbine output power. In this paper, three different methods for estimating average wind turbine power are studied and compared with the real power from a 2.5 MW Clipper wind turbine installed in Kirkwood. The results show that all utilized methods have an acceptable accuracy. Additionally, the effectiveness of the recorded wind speed noises on the wind turbine power and the amount of hydrogen is evaluated. As expected, the increase of the signal-to-noise ratio leads to a lower error. The results showed that if the hydrogen generated by the electrolyzer be used in transportation industry, the identified wind turbine can create the required hydrogen amount for averagely 43 cars/day.

Sustainability of a wind-hydrogen energy system: Assessment using a novel index and comparison to a conventional gas-fired system

This study applies a previously developed methodology to assess the sustainability of a wind-hydrogen system designed to meet the energy needs of a small community in southern Ontario. A thermodynamic analysis demonstrates that the energy system can meet the heating, cooling, and electrical energy needs of the 50-household community with a wind turbine rotor radius of 28 m and hydrogen storage capacity of 8550 kg. A subsequent multi-criteria assessment reveals that the Integrated Sustainability Index (ISI) is particularly sensitive to weighting factors associated with Affordability, Global Warming Potential, and Stratospheric Ozone Depletion Potential sub-indicators. Although the individualist ISI only varies from 0.77 to 0.90, the egalitarian ISI varies from 0.30 to 0.75 over a range of weighting factors. A comparative assessment of a wind-hydrogen and traditional gas-fired system shows that there is very little difference in the ISI of each system. The individualist ISI is 0.84 and 0.86 and the egalitarian ISI is 0.56 and 0.52 for the wind-hydrogen and gas-fired system, respectively. This suggests that superficial assessments of sustainability should be avoided and that multi-criteria analysis is essential.

Optimization of operating parameters in a hybrid wind–hydrogen system using energy and exergy analysis: Modeling and case study

In this study, hybrid renewable energy system based on wind/electrolyzer/PEM fuel cell are conceptually modeled, and also, exergy and energy analysis are performed. The energy and exergy flows are investigated by the proposed model for Khaf region-Iran with high average wind speed and monsoon. Exergy and energy analysis framework is made based on thermodynamic, electro-chemical and mechanical model of the different component of hybrid system. Also, the effects of various operating parameters in exergy efficiency are calculated. The results show an optimum wind speed where the exergy efficiency and power coefficient is at maximum level, and also, when the ambient temperature start to be increased in wind turbine, the efficiencies decrease by a great deal for constant wind speeds. Also, the optimum temperature is calculated by exergy analysis in electrolyzer and fuel cell as 353 and the exergy efficiency of electrolyzer decreases by increasing the membrane thickness. Furthermore, pressure changes affect exergy and energy efficiency in PEM fuel cell. Finally, the electrolyzer and fuel cell efficiencies are calculated as 68.5% and 47% respectively.

Modelling and simulation of a wind-hydrogen CHP system with metal hydride storage

Abstract This paper describes the modelling and simulation of a wind-hydrogen system aimed at supplying electrical and thermal residential loads, where the thermal load is in part supplied by a catalytic hydrogen combustion device with hydrogen stored in a metal hydride system composed of a cluster of five metal hydride tanks equipped with a metal foam heat exchanger. The complete mathematical model has been developed from models available in literature and describing the different sub-systems that constitute the overall wind-hydrogen system. It has been later implemented in a multi-domain software environment to simulate system operations. Results over a year-long simulation show complete stand-alone capabilities, with an electrical efficiency and a combined heat and power efficiency of 8.2% and 12.5% respectively. At the end of the simulation period, a hydrogen annual surplus of 110.5 kg is left over which can, for instance, be used to feed a hydrogen powered car for about 9500 km.

Simulation of PV–Wind-hybrid systems combined with hydrogen storage for rural electrification

Since many years, engineering, research and development of hybrid systems for rural electrification are strongly supported by computer simulations. Different software packages have been used according to the required level of details along with the progress of the project HYRESS. For the development of optimal system control and load/energy management strategy, different simulation models from APL (Alternative Power Library) have been used for a Hybrid PV–wind-hydrogen system that will be installed in the Essaouira region in Morocco. This library provides models developed by IWES for the simulation of regenerative power supply systems and it is used to investigate the integration of a hydrogen storage path in hybrid system operation.

Influence of wind turbine power curve and electrolyzer operating temperature on hydrogen production in wind–hydrogen systems

Current simulation tools used to analyze, design and size wind–hydrogen hybrid systems, have several common characteristics: all use manufacturer wind turbine power curve (obtained from UNE 61400-12) and always consider electrolyzer operating in nominal conditions (not taking into account the influence of thermal inertia and operating temperature in hydrogen production). This article analyzes the influence of these parameters. To do this, a mathematical wind turbine model, that represents the manufacturer power curve to the real behaviour of the equipment in a location, and a dynamic electrolyzer model are developed and validated. Additionally, hydrogen production in a wind–hydrogen system operating in “wind-balance” mode (adjusting electricity production and demand at every time step) is analyzed. Considering the input data used, it is demonstrated that current simulation tools present significant errors in calculations. When using the manufacturer wind turbine power curve: the electric energy produced by the wind turbine, and the annual hydrogen production in a wind–hydrogen system are overestimated by 25% and 33.6%, respectively, when they are compared with simulation results using mathematical models that better represent the real behaviour of the equipments. Besides, considering electrolyzer operating temperature constant and equal to nominal, hydrogen production is overestimated by 3%, when compared with the hydrogen production using a dynamic electrolyzer model.

Life cycle environmental and economic analyses of a hydrogen station with wind energy

This study aimed to identify the environmental and economic aspects of the wind-hydrogen system using life cycle assessment (LCA) and life cycle costing (LCC) methodologies. The target H 2 pathways are the H 2 pathway of water electrolysis (WE) with wind power (WE[Wind]) and the H 2 pathway of WE by Korean electricity mix (WE[KEM]). Conventional fuels (gasoline and diesel) are also included as target fuel pathways to identify the fuel pathways with economic and environmental advantages over conventional fuels. The key environmental issues in the transportation sector are analyzed in terms of fossil fuel consumption (FFC), regulated air pollutants (RAPs), abiotic resource depletion (ARD), and global warming (GW). The life cycle costs of the target fuel pathways consist of the well-to-tank (WTT) costs and the tank-to-wheel (TTW) costs. Moreover, two scenarios are analyzed to predict potential economic and environmental improvements offered by wind energy-powered hydrogen stations. In LCA results, WE[Wind] is superior to the other pathways in all environmental categories. The LCC results show that the projected WTT cost savings of WE[Wind] and WE[KEM] compared to gasoline are US $ 0.050 and US $ 0.036 per MJ, respectively, because hydrogen will not be subjected to any fuel tax according to the Korean Energy Policy in 2015. Although WE[KEM] and WE[Wind] incur high capital costs owing to the required capital investment in fuel cell vehicles (FCVs), they have lower well-to-wheel (WTW) costs than those of conventional fuels due to the high FCV efficiency in fuel utilization stage. WTW costs for gasoline are higher than those of WE[KEM] and WE[Wind] by US $ 12,600 and US $ 10,200, respectively. This study demonstrated the future competitiveness of the WE[Wind] pathway in both environmental and economic aspects. In the WTT stage, the point-of-sale of the electricity produced by the wind power plant (WPP) cannot be controlled because the wind-powered electricity production fluctuates considerably depending on the wind. However, the use of a wind-powered H 2 station in the future enables stable wind power plant management and provides greater economic profit than the present system since the wind-powered electricity can be used for the hydrogen production in the H 2 station and any residual electricity is sold to Korea electric power corporation (KEPCO). If 5% of conventional vehicles in Korea are substituted with FCVs using H 2 via WE[Wind] in 2015, CO 2 emission will be reduced by 2,876,000 tons/year and annual LCC costs by US $ 8559 million. Thus, the operation of wind-powered hydrogen stations will encourage the introduction of hydrogen into the transportation fuel market.

An assessment of wind-hydrogen systems for light duty vehicles

A hydrogen economy could offer energy stability, economical, and environmental benefits. In this paper, a hydrogen system based on wind-generated electricity is presented as a viable component in a hydrogen transition strategy. The strengths of a wind-hydrogen system are exhibited in its modular design, exploitation of existing technology, and utilization of a renewable resource. Specifically, a state level assessment of wind power was conducted in order to determine the ability of individual states to meet light-duty vehicle hydrogen fueling demands while utilizing the proposed system. Additionally, analysis related to existing hydrogen resources is presented in order to form a transition scenario.

Generation management using batteries in wind farms: Economical and technical analysis for Spain

This paper presents an hourly management method for energy generated in grid-connected wind farms using battery storage (Wind–Batteries systems). The method proposed is analysed technically and economically. Electricity generation in wind farms does not usually coincide with the electrical demand curve. If the wind-power penetration becomes high in the Spanish electrical grid, energy management will become necessary for some wind farms. A method is proposed in this paper to adjust the generation curve to the demand curve by storing electrical energy in batteries during off-peak hours (low demand) and selling stored energy to the grid during peak hours (high demand). With the results obtained and reported in this paper, for a Wind–Batteries system to be economically as profitable as a Wind-Only system, the selling price of the energy provided by the batteries during peak hours should be between 22 and 66 c€/kWh, depending on the technology and cost of the batteries. Comparison with flexible thermal generation has been performed. Additionally, the results are compared with those obtained if using hydrogen (Wind–Hydrogen system, which uses an electrolyser, hydrogen tank, and fuel cell instead of batteries), concluding that the Wind–Batteries system is both economically and energetically far more suitable.

Hourly energy management for grid-connected wind–hydrogen systems

This paper is a complete technical–economic analysis of the hourly energy management of the energy generated in wind–hydrogen systems. Wind power generation depends on the unpredictable nature of the wind. If the wind-power penetration becomes high in the Spanish electrical grid, energy management will be necessary for some wind farms. A method is proposed in this paper to adjust the generation curve to the demand curve, consisting of the generation of hydrogen and storing it in a hydrogen tank during off-peak (low demand) hours, while during the rest of the hours (peak hours, high demand) the stored hydrogen can be used to generate electricity. After revising the results obtained in this paper, for the current values of efficiency of the electricity-hydrogen-electricity conversion (approximately 30%) and due to the high cost of the hydrogen components, for a wind–hydrogen system to be economically viable the price of the sale of the energy generated by the fuel cell would be very high (approximately 171 c€/kWh).

Hydrogen storage for mixed wind–nuclear power plants in the context of a Hydrogen Economy

A novel methodology for the economic evaluation of hydrogen production and storage for a mixed wind–nuclear power plant considering some new aspects such as residual heat and oxygen utilization is applied in this work. This analysis is completed in the context of a Hydrogen Economy and competitive electricity markets. The simulation of the operation of a combined nuclear–wind–hydrogen system is discussed first, where the selling and buying of electricity, the selling of excess hydrogen and oxygen, and the selling of heat are optimized to maximize profit to the energy producer. The simulation is performed in two phases: in a pre-dispatch phase, the system model is optimized to obtain optimal hydrogen charge levels for the given operational horizons. In the second phase, a real-time dispatch is carried out on an hourly basis to optimize the operation of the system as to maximize profits, following the hydrogen storage levels of the pre-dispatch phase. Based on the operation planning and dispatch results, an economic evaluation is performed to determine the feasibility of the proposed scheme for investment purposes; this evaluation is based on calculations of modified internal rates of return and net present values for a realistic scenario. The results of the present studies demonstrate the feasibility of a hydrogen storage and production system with oxygen and heat utilization for existent nuclear and wind power generation facilities.