Fuel Cell Microgrid Research Articles

Control and management of a fuel cell microgrid. Energy efficiency optimization

Increasing the efficiency of energy conversion systems is a relevant aspect to decrease the oil dependence and to minimize environmental impact. Considering the inherent characteristics of the PEM fuel cells, this paper proposes a control algorithm for a microgrid consisting of two fuel cells, in order to improve its energy efficiency. To do this, hardware responsible for managing the microgrid has been designed and implemented and the proposed control algorithm has been applied. Various tests have been performed on the microgrid, analysing its behaviour in each case.

Optimal sizing, operation strategy and case study of a grid-connected solid oxide fuel cell microgrid

The microgrid (MG) system based on renewable energy generators plays a significant role in sustainable development and environmental protection, which has been developed rapidly. As a promising clean energy conversion technology, solid oxide fuel cell (SOFC) is a clean, efficient and controllable power generator, which is very suitable to be integrated in a distributed MG system. Finding the optimal size configuration and the beneficial operation strategy of the Grid-connected MG under different operation modes are critical issues for MG application. In this work, a single-dwelling MG incorporating solar photovoltaic (PV), wind turbine generator (WTG), SOFC and battery energy storage system (BESS) is studied by minimizing the system levelized cost of energy (LCOE) on the basis of system multi-constraints. The dispatching problem of MG is modeled as a quadratic programming problem and an improved GA-PSO algorithm is employed to explore the optimal configuration. Then, sensitivity analysis is carried out to identify the impact of different distributed energy resource size on the performance of MG. Based on the optimal configuration, the operation strategy of the proposed MG under both off-grid mode and grid-connected mode, as well as the influence of electricity price and fuel price on the operation of the MG are investigated. Finally, the economic and environmental benefits of the MG are studied and compared. The results show that, in Shanghai, Beijing, Wuhan and Hulunbuir, the costs of the MG in both off-grid mode and grid-connected mode are lower than the grid-supplied price by up to 13%-28% and 28%-37% separately.

Advanced controller design based on gain and phase margin for microgrid containing PV/WTG/Fuel cell/Electrolyzer/BESS

Nowadays, with the increase in the amount of power generation related to renewable energy resources, the need for energy storage and management is raised. In this regard, the hydrogen energy plays a critical role in the development of renewable technologies. In view of the above, advanced controller design is presented in this paper to effectively perform load frequency control of islanded fuel cell microgrid based on the wind turbine, photovoltaic, fuel cell, electrolyzer, battery energy storage systems, and residential and commercial loads. The controller design is based on the determination of the controller parameters that the fuel cell microgrid system will provide the desired dynamic properties. In the proposed controller design, virtual gain and phase margin testers are added to provide the desired dynamic properties. The controller's stable parameter plane is determined with the help of the stability boundary locus method, taking into account time delay, gain, and phase margin. First, the accuracy of the stable parameter plane determined for the proposed controller design is demonstrated by means of time domain and eigenvalue analyzes. Finally, in order to show the performance of the advanced controller design and the success of the fuel cell as a backup generator, analysis studies have been carried out using actual data of solar and wind, and appropriate changes of load in studied microgrid.

The effects of the FOPI controller and time delay on stability region of the fuel cell microgrid

In this paper, the effects of the time delay (τ) and the order of the fractional integral (λ) on the stable parameter region of the FOPI controller for a fuel cell microgrid is investigated. The stability boundary curves depending on λ and τ values of the fuel cell microgrid, i.e., stable parameters space of the FOPI controller, are obtained by using the stability boundary locus (SBL) method. The SBL is a graphical technique and in this technique, the stable regions of the system are obtained by using the characteristic equation of the system. The obtained stable regions are tested by the time-domain simulations and the generalized and modified Mikhailov (GMM) criterion. The effect of τ and λ on the stable parameter region of the FOPI controller for a fuel cell microgrid with time delay has been shown in the literature for the first time through this study. The obtained results show that τ and λ have considerable effects on the change of stable region. The results also show that the effect of λ is much higher than the τ′s effect. Therefore, it has been demonstrated that the effect of the large time delay, which makes the system unstable, can be reduced by λ in this study.

Modelling of a Solid Oxide Fuel Cell Microgrid System for a Megawatt Load

Fuel cell systems are expected to play a key role for power generation in various applications ranging from domestic, commercial to industrial. A solid oxide fuel cell is one of the types which is suitable for high-power demand. It can power diverse systems including trains, ships, vehicles as well as supplying industrial and residential loads. In this study, a microgrid using a 1.4 MW solid oxide fuel cell is considered operating in grid connection mode under 600 volts. A grid connected inverter is modelled and controlled as a closed loop control system to supply a 1.2 local load while feeding any excess into the grid. The inverter control scheme comprises voltage and current regulators to provide a good power factor and satisfy synchronisation requirements with the utility grid in synchronous frame. The frequency and phase of the inverter are synchronised with those of the grid through a phaselocked-loop. An LCL filter serving as an interface between the inverter and the grid is used to minimise harmonics produced by the grid-connected inverter. Matlab/Simulink environment is used for the modelling and simulation. The results obtained show good performance of the proposed microgrid as well as the inverter design and control approach with a low total harmonic distortion of about 0.5%.

US Navy sub base breaks ground on FCE fuel cell microgrid

The US Naval Submarine Base New London (SUBASE) in Groton, Connecticut has begun construction of its 7.4 MW fuel cell park, which features two SureSource 4000™ molten carbonate fuel cell power plants from FuelCell Energy to generate power for the base and local power grid.

FuelCell Energy wins 40 MW of projects for Long Island, completes university microgrid

Connecticut-based FuelCell Energy has been awarded three fuel cell projects, totaling 39.8 MW, by Long Island Power Authority (PSEG Long Island). FCE has also completed a 1.4 MW molten carbonate fuel cell microgrid at the University of Bridgeport, successfully proving grid-independent operation.

AFC Energy to build Surrey fuel cell microgrid

AFC Energy to build Surrey fuel cell microgrid

水素貯蔵システムを用いた燃料電池マイクログリッドに関する研究

水素貯蔵システムを用いた燃料電池マイクログリッドに関する研究

Installation planning of a battery for stand-alone fuel cell microgrid

Installation planning of a battery for stand-alone fuel cell microgrid

Bloom, Constellation start work on fuel cell microgrid in Hartford

The City of Hartford in Connecticut, energy supplier Constellation, and Bloom Energy have begun construction of a fuel cell powered microgrid system to help manage electricity costs and supply emergency power to part of the city's Parkville neighbourhood.

A study of the installed capacity and electricity quality of a fuel cell-independent microgrid that uses locally produced energy for local consumption

SUMMARY Reducing the rates of nuclear power generation for all electric power sources has been seriously discussed in Japan since the accident at the Fukushima No. 1 nuclear power plant in March 2011. Thus, the distributed power supply is expected to expand. The local production of safe and clean energy for local consumption is greatly needed in Japan. In this paper, the Saroma Lake green microgrid (SLMG), a fuel cell microgrid using tidal power generation and photovoltaics, has been planned. Energy balance equations were used to investigate this system's method of operation. Further simulated analysis of the facility, its operation cost, and the electric power quality of the network were conducted using MATLAB/Simulink, and the relationships among the capacity of a facility, the cost, and supply rate of green energy and the electric power quality (interphase voltage, frequency, and higher harmonic wave) of the power network were clarified. The total projected cost of the equipment and operation for introducing the proposed SLMG is ¥1,500,000,000/10 years. Increasing the supply rate of green energy and reducing the facility cost will require the introduction of biofuels and the reduction of the facility costs of solid oxide fuel cells in the SLMG. Copyright © 2012 John Wiley & Sons, Ltd.

Optimization of equipment capacity and an operational method based on cost analysis of a fuel cell microgrid

A microgrid requires a stable supply of electric power and heat, which is achieved by the cooperative operation of two or more pieces of equipment. The equipment capacity and the operational method of the equipment were optimized using a newly developed orthogonal array-GA (genetic algorithm) hybrid method for an independent microgrid accompanied by a fuel cell cascade system, solar water electrolysis, battery, and heat storage. This type of system had not been hardly developed until now. The objective function of the proposed system was the minimization of the total amount of equipment and fuel cost over ten years. For the first step in the proposed analysis method, the capacity of each piece of equipment and the operational method, which are considered to be close to the optimal solution of the system, are combined using the orthogonal array and factorial-effect chart, which are an experimental design technique. In the next step, the combination described above provides the initial values to the GA, and the GA searches for the optimal capacity and operational method for each piece of equipment in question. Compared with a simple GA, the convergence characteristic improves greatly using the proposed analysis method developed in this study.

Installation Plan of a Fuel Cell Microgrid System Optimized by Maximizing Power Generation Efficiency

If energy-supplying microgrids can be arranged to operate with maximal efficiency, this will have a significant influence on the generation efficiency of the grid and will reduce greenhouse gas production. A means of optimizing the microgrid needs to be developed. Moreover, microgrids that use proton exchange membrane-type fuel cells (PEM-FCs) may significantly reduce the environmental impact when compared with traditional power plants. The amount of power supplied to the grid divided by the heating value of the fuel is defined as the system generation efficiency. The authors find that when a set of PEM-FCs and a natural gas reformer are connected to the microgrid in an urban area, the annual generation efficiency of the system slightly exceeds 20%. When a PEM-FC follows the electricity demand pattern of a house, it operates at a partial load most of the time, resulting in a low efficiency of the microgrid. A method of improving the generation efficiency of a fuel cell microgrid is proposed, where a supply system of power and heat with a high energy efficiency are constructed. In this paper, a method of installing two or more microgrids is proposed (known as the partition cooperation system). The grids can be connected in an urban area to maximize generation efficiency. Numerical analysis shows that the system proposed in this paper (which has an annual generation efficiency of 24.6–27.6%) has a higher generation efficiency than conventional PEM-FC systems (central generating systems have annual generation efficiencies of 20.6–24.8%).

Compound microgrid installation operation planning of a PEFC and photovoltaics with prediction of electricity production using GA and numerical weather information

A fuel cell microgrid with photovoltaics effectively reduces greenhouse gas emission. A system operation optimization technique with photovoltaics and unstable power is important. In this paper, the optimal operation algorithm of this compound microgrid is developed using numerical weather information (NWI) that is freely available. A GA (genetic algorithm) was developed to minimize system fuel consumption. Furthermore, the relation between the NWI error characteristics and the operation results of the system was clarified. As a result, the optimized operation algorithm using NWI reduced the energy cost of the system.

Dynamic Characteristic of a Fuel Cell Micro-Grid Using an Engine Generator to Base Load Operation

The dynamic of a micro-grid consisting of an engine generator and sixteen fuel cells was clarified by the transfer function model using actual data from power generators. The micro-grid was composed of a 3kW engine generator and 1kW fuel cells, and the dynamic characteristics of the grid were analyzed using the energy demand model in February of a cold region. Consequently, the settling time (Time taken to converge on ±5% of the limit of an output target) of a micro-grid is 15 seconds from 10 seconds. The control parameter of a fuel cell system is significantly influenced by the settling time and overshooting of a micro-grid. Since any excess and deficiency in electric power can respectively be covered if two or more fuel cells are connected with a grid, the instant electric power demand load peak can be distributed. Compared with the number of fuel cells required when installing independently, the number of installations can be reduced for a micro-grid system.

Arrangement plan for distributed fuel cells installed in urban areas

The independent fuel cell micro-grid that accommodates power and heat independently without connecting with other power systems is expected to back up power supply in an emergency, and at peak cuts of a power plant, and the effective use of exhaust heat is anticipated. Therefore, this paper analyses the cost minimization problem of the arrangement planning of a fuel cell system, and the feeding order of exhaust heat. An analysis programme for operation plan at the time of connecting a distributed fuel cell with an energy network was developed using a genetic algorithm. The fuel cell energy network was optimized in six buildings to minimize operation costs, facility costs, and the installation costs of the facilities. As a result, the analysis method for the arrangement plan for the capacity of each installed fuel cell, boiler, heat storage tank, and hot-water circulating pump was clarified. If the hot-water network of the distributed fuel cell is installed, in the winter of a cold district, facility cost is disadvantageous compared with the conventional method. Copyright © 2007 John Wiley & Sons, Ltd.

Power characteristics of a fuel cell micro-grid with wind power generation

An independent micro-grid connected with renewable energy has the potential to reduce energy costs, and reduce the amount of greenhouse gas discharge. However, the frequency and voltage of a micro-grid may not be stable over a long time due to the input of unstable renewable energy, and changes in short-period power load that are difficult to predict. Thus, when planning the installation of a micro-grid, it is necessary to investigate the dynamic characteristics of the power. About the micro-grid composed from 10 houses, a 2.5 kW proton exchange membrane fuel cell is installed in one building, and it is assumed that this fuel cell operated corresponding to a base load. A 1 kW PEM-FC is installed in other seven houses, in addition a 1.5 kW wind turbine generator is installed. The micro-grid to investigate connects these generating equipments, and supplies the power to each house. The dynamic characteristics of this micro-grid were investigated in numerical analysis, and the cost of fuel consumption and efficiency was also calculated. Moreover, the stabilization time of the micro-grid and its dynamic characteristics accompanied by wind-power generation and fluctuation of the power load were studied.

Analysis of a fuel cell micro-grid with a small-scale wind turbine generator

If electric power is supplied using an independent micro-grid connected to renewable energy, it can flexibly match the energy demand characteristics of a local area. And an independent micro-grid is expected to be effective in cutting greenhouse gas discharge and energy costs, as well as in eliminating the need for an emergency power supply system. Since the output of renewable energy is unstable, other energy equipment needs to cover the stability of output. Thus, the operating conditions of an independent micro-grid that supplies power with natural power sources and fuel cells are investigated. The operation conditions of a fuel-cell independent micro-grid with wind power generation were investigated by numerical analysis. Step loads and an apartment house power load model were analyzed using the dynamic characteristics of a fuel cell obtained from experiments. The output of wind power generation and fuel cells is controlled by proportional-integral control of an independent micro-grid for rapid power demand change.

Load response characteristics of a fuel cell micro-grid with control of number of units

The dynamic characteristics and generation efficiency of a micro-grid structured from 17 houses were examined. A gas engine generator with a power generation capacity of 3 kW installed in a house is made to correspond to the base load, and a solid-polymer-membrane-type fuel cell with a power generation capacity of 1 kW is installed in 16 houses. Moreover, when changing the load of a micro-grid, the correspondence takes place by controlling the number of fuel cells. Using numerical analysis, the characteristics of the power quality of a fuel cell micro-grid, and the generation efficiency of the fuel cell were examined. As a result, the relationship between the parameter of the controller and power quality and a fall in generation efficiency by a partial load was clarified.