R E S E A R C H A R T I C L E
Open Access
Scenario analysis of a bioethanol fueled hybrid
power generation system
Wei Wu
1*, Yuan-Tai Hsu
2and Po Chih Kuo
1Abstract
Background: Regarding most of FC/PV/Battery based hybrid power generation systems, the photovoltaic (PV) power usually dominates the main power supply and the water electrolyzer is used to produce hydrogen. The energy efficiencies of these hybrid power generation (HPG) systems are usually low due to the low conversion efficiency of PV cell and the extra power consumption to hydrogen production. To reduce the electricity demand by the PV system and improve the energy efficiency of hydrogen production unit, a scenario-based design of the HPG system is necessary.
Result: This paper proposes an EFC/PV/Battery based hybrid power generation system to meet 24-hour power demand. An ethanol-fueled fuel cell (EFC) power generator not only dominates the main power supply, but also a combination of the stand-alone EtOH-to-H2 processor and PEMFC can ensure higher energy efficiency. A PV system is treated as an auxiliary power generator which can reduce the (bio)ethanol consumption. A backup battery not only stores excess power from PV or EFC, but also it can precisely satisfy the power demand gap. Finally, scenario analysis of the hybrid power generation (HPG) system in regard to the hybrid power dispatch and energy efficiency is addressed.
Conclusion: An optimized fuel processing unit using ethanol fuel can produce high-purity hydrogen. The simulation shows that the stand-alone EtOH-to-H2 processor not only guarantee the high energy efficiency, but also it can continuously produce hydrogen if the fuel is enough. According to scenarios for the daily operation of the HPG system, the EFC power dominates the power supply during the night, the PV system dominates the power supply during the day and the backup battery aims to instantly compensate the power gap and store the excess power from PV or EFC. According to the hybrid power dispatch, the distribution of the HPG system efficiency is specified.
Keywords: Hybrid power system, Scenario analysis, Ethanol-fueled fuel cell system, Energy efficiency Background
Recently the interest in renewable and sustainable power generation techniques such as photovoltaic, wind, and fuel cell powered systems has grown. The off-grid hybrid power system is increasingly popular for remote area power generations, even though the photovoltaic (PV) or wind system is highly dependent on weather conditions and locations. Muselli et al. [1] developed a stand-alone hybrid power system which was composed of the PV panels, an electrical generator using fossil fuels, and battery storage, and Elhadidy [2] studied the feasibility
of using wind/solar/diesel energy conversion systems to meet the power demand of the specific community in Saudi Arabia. Notably, a gasoline or diesel engine is usually treated as the backup power generator.
The PV system generates electricity during daylight hours, but the fuel cell system produces electricity as long as hydrogen is supplied. To address the clean power generation system, Hwang et al. [3] proposed a solar/fuel cell hybrid power system to meet the daily load demand of a typical family in Taiwan, Uzunoglu et al. [4] inves-tigated dynamic models and simulation of this kind of hybrid power generation systems with appropriate control strategies, and Zervas et al. [5] provided an optimal decision framework for managing the hybrid energy systems. Similarly, these hybrid systems all involve the water * Correspondence:[email protected]
1
Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
Full list of author information is available at the end of the article
© 2014 Wu et al.; licensee Chemistry Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
electrolyzer for producing hydrogen. The electrolyzer is simpler and does not require complex units, but there is no solution to reduce its large electricity consumption. For most of hybrid systems, the PV panel is larger so as to carry out water electrolysis by using the excess power. Therefore, the overall energy efficiency is quite low [6].
The hydrogen fuel cells have been considered the most promising for automotive application, but the guidelines for the hydrogen storage, safer operation and transporta-tion are quite rigorous [7]. The fossil fuel processing unit could produce the high purity of hydrogen [8,9], but the external energy supply and large carbon emissions are not avoided. If biomass can replace fossil fuels as the feedstock, the net-zero greenhouse gas (GHG) emissions of hydrogen production systems can be achieved. Liquefied ethanol is a popular feedstock because it is easily made by fermentation, no compressed storage is needed, and lower operating temperatures are required for reforming processes [10,11]. In this paper, an ethanol fueled HPG system is proposed. The modeling, optimization and design of the EtOH-to-H2 processor is achieved by using Aspen Plus. The scenario analysis of the HPG system in regard to the daily load demand of a typical family in Taiwan [3] is investigated in Matlab. Since the EFC power unit cannot rapidly meet the load demand due to complicated chemical reactions in the ethanol reforming process, the lithium-ion battery is considered to meet the power gap when the excess power from PEMFC and PV units have been completely stored in the battery in advance. According to prescribed hybrid power dispatch, it is verified that the energy efficiency of the proposed HPG system is superior to the other renewable hybrid energy system.
Hybrid power generation system
The ethanol-fueled HPG system is shown in Figure 1. Both PV generator and PEMFC stack are treated as power sources. The lithium-ion battery is denoted as an electricity
storage/instant supply device. The stand-alone EtOH-to-H2 processor in place of the devices of the hydrogen stor-age tank and water electrolyzer aims to produce high purity hydrogen. Other devices, including converters/ inverters and power management (DC bus), are used to meet the voltage specification.
EtOH-to-H2processor
The EtOH-to-H2processor shown in Figure 2 is consid-ered as a stand-alone hydrogen production system, which is composed of an ethanol steam reforming (ESR) reactor, a low-temperature water-gas-shift (LTWGS) re-actor, the pressure swing adsorption (PSA) unit, and a burner. The simple heat integration is adopted to im-prove the water heat recovery; (i) the waste heat gener-ated from the burner is applied to preheat the mixing feed flow using a heat exchanger (HEX1) and then meets the heat demand of the reforming reactions in the ESR reactor; (ii) the inlet water flow is preheated by a heat exchanger (HEX2) to increase the feed temperature; (iii) the temperature of flue gas discharged from the heating jacket of the ESR reactor is expected to be low.
ESR reactor
According to the kinetic experiments for the ethanol steam reforming reactions over Co3O4-ZnO catalyst at atmospheric pressure and temperature in the 600-800 K range [12], first the reactions of ESR are shown as:
C2H5OH→CH3CHOþ H2ð Þ; ΔHr1 01¼ 71 kJmol−1 ð1Þ
C2H5OH→CO þ CH4þ H2ð Þ; ΔHr2 02¼ 52:9 kJmol−1 ð2Þ
COþ H2O↔CO2þ H2ð Þ; ΔHr3 03¼ −34:5 kJmol−1 ð3Þ
CH3CHOþ 3H2O→2CO2þ 5H2ð Þ; ΔHr4 04¼ 127:4 kJmol−1
ð4Þ
Second, the kinetic models of four reactions (r1,…, r4) are expressed by power-law rate expressions [12]:
r1¼ 2:1 104exp − 70 R 1 TESR− 1 773 PC2H5OH ð5Þ r2¼ 2:0 103exp − 130 R 1 TESR− 1 773 PC2H5OH ð6Þ r3¼ 1:9 104exp − 70 R 1 TESR− 1 773 PCOPH2O− PC2OPH2 exp 4577:8T ESR −4:33 0 @ 1 A ð7Þ r4¼ 2:0 105exp − 98 R 1 TESR− 1 773 PCH3CHOP 3 H2O ð8Þ where TESR is the temperature of the ESR reactor, Pi
(i = C2H5OH, CO, H2O, …) is corresponding partial
pressure, and R is the universal gas constant. Moreover, the one-dimensional, pseudo-homogeneous model is built by the Aspen Plus. The assumptions for the steady-state simulation of the ESR reactor include gas phase reactions, plug-flow reactor, and no pressure drop. The thermo-dynamic properties of some species are evaluated by using the Peng-Robinson equation of state. Other parame-ters include the fluid density = 0.02 kmol m-3, catalyst weight = 5 kg, and sizes of the reactor with the diameter and length of the reactor D = 0.5 m and L = 1.5 m.
LTWGS reactor
To reduce CO as well as enhance hydrogen yield, the LTWGS reactor could be directly connected to the ESR reactor, where the reaction scheme is:
COþ H2O
↔
Cat
CO2þ 2H2; Δ ^HoR¼ −41:15 kJmol −1
ð9Þ For a moderately exothermic reaction with Sud-Chemie commercial available catalysts, we assume that the reactor is adiabatic and the operating temperature is between 400 K and 600 K. Moreover, the kinetic model is described by [13], rW ¼ 82:2 exp − 47400 RTWGS PCOPH2O− PCO2PH2 KWGS ð10Þ where TWGSis the temperature of the WGS reactor and
KWGS is the equilibrium constant of the WGS reaction
shown by ln Kð WGSÞ ¼5693:5 TWGS þ 1:077 ln Tð WGSÞ þ 5:44 10 −4T WGS −1:125 10−7T2 WGS− 49170 T2WGS −13:148 ð11Þ Burner
Regarding the design of burner, we assume that (i) H2is completely separated by PSA, (ii) all components of the burner are completely burned, and (iii) its Aspen module Figure 2 Stand-alone EtOH-to-H2processor.
is considered as an adiabatic and stoichiometric reactor. The combustion reaction in the burner is shown as follows:
C2H5OHþ 3O2→2CO2þ 3H2O; Δ ^Hob;EtOH¼ −1279 kJmol−1
ð12Þ CH4þ 2O2→CO2þ 2H2O; Δ ^Hob;CH4¼ −803:1 kJmol −1 ð13Þ H2þ 1 2O2→H2O; Δ ^H o b;H2¼ −242 kJmol −1 ð14Þ COþ1 2O2→CO2; Δ ^H o b;CO¼ −283 kJmol−1 ð15Þ Sensitivity analysis
Regarding the effect of fuel utilization, the ratio of hydrogen to ethanol (H2/C2H5OH) is specified by adjusting ethanol flow or water flow in the feed.
I. The profiles of H2/C2H5OH vs. S=Cð ÞjH2Oat different TESR,inis depicted in Figure3(a). It shows
that the maximum hydrogen yield can be achieved by adjusting the water flow at constant ethanol flow. The profiles of H2/C2H5OH vs. (S/C)|EtOHat
different TESR,inis depicted in Figure3(b). Similarly,
it shows that the maximum hydrogen yield is obtained by adjusting the ethanol flow at constant water flow. The corresponding operating ranges are bounded by 2≤ S=Cð ÞjEtOH;H2O≤2:5 and 600K ≤
TESR,in≤ 800K. Notably, the manipulation of ethanol
flow can ensure the larger hydrogen yield than the water flow at the same TESR,in, and the increase of
TESR,incannot induce the high hydrogen yield.
According the heat recovery design, the waste gas temperature at the outlet of heating jacket decreases when the preheated temperature of ESR increases. The low reactor temperature would reduce the conversion of ethanol reforming reactions.
II. According to the sensitivity analysis by adjusting one variable (S/C)|EtOH, the optimization tool of Aspen
Plus is employed to determine the optimal operating conditions, S=Cð ÞjEtOH¼
27:2 kgmol=hr
12:7 kgmol=hr= 2.14 at
TESR,in=600 K. The steady-state simulation of the
system at optimal conditions is shown in Figure4, where the flowrate of hydrogen product can achieve 55.62 kgmol/hr, i.e. H2/C2H5OH =4.38 and the
ethanol conversion can achieve 95%. PEM fuel cell system
A Ballard 5 kW PEMFC stack system consists of 30 cells connected in series to provide output current up to 100 A, which is directly connected to an ethanol-to-hydrogen processor. The high purity of hydrogen produced from the processor is fed to the anode and the excess hydrogen
needs to be recirculated. Referring to an empirical fuel cell stack model by [14,15], the output voltage of a single fuel cell (Vfc) is expressed by
Vfc¼ E − Vact− Vohm ð16Þ
(i) The open circuit cell potential E via the Nernst equation is described by E¼ 1:229 − 8:5 10−4 Tfc− 298:15 þRTfc 2F ln PH2ðPO2Þ 0:5 h i ð17Þ (ii) The activation overvoltage Vactis described by a
first-order dynamic with the effects of double layer capacitance charging at the electrode-electrolyte interfaces dVact dt ¼ ifc Cdlþ ifcEact VactCdl ð18Þ
where the activation drop Eactis defined by
Eact¼ β1þ β2Tfcþ β3Tfcln Cð O2Þ þ β4Tfcln ið Þ ð19Þc
and the parametric coefficientsβ1,…, β4are expressed by
β1¼ −0:948 β2¼ 0:00286 þ 0:0002 ln Afc þ 4:3 10−5ln C H2 ð Þ β3¼ 7:6 10−5 β4¼ −1:93 10−4 ð20Þ and CO2¼ 1:97 10 −7P O2exp 498 Tfc CH2¼ 9:174 10 −7P H2exp −77 Tfc ð21Þ
(iii) The ohmic overvoltage is given by: Vohm¼
lm
Afc
rMifc ð22Þ
where the membrane resistivity rMis described by
rM¼ 181:6 1 þ 0:03 ifc Afc þ 0:062 Tfc 303 2 i fc Afc 2:5 11:866−3 ifc Afc h i exp 4:18 Tfc−303 Tfc h i ð23Þ
Figure 4 Optimization and simulation of EtOH-to-hydrogen processor.
Above of all parameters for modeling the PEMFC system have been defined in the nomenclature section. Based on the ideal gas law and the principle of mole conservation, the partial pressures of hydrogen ( pH2) and oxygen (pO2) associated with reactant flow rates at the anode and cathode along with the cell current are modeled as. dpH2 dt ¼ RTfc Van _mH2;in− kan pH2− pH2;in −15 F ifc ð24Þ dpO2 dt ¼ RTfc Vca _mO2;in− kca pO2− pBPR −7:5 F ifc ð25Þ Notably, two pressure regulators with fixed parameters (kan, kca) are added to manipulate the outlet hydrogen
flow at the anode and the outlet oxygen flow at the cathode. The above model equations show that the fuel cell performance is affected by current density (ifc), fuel cell temperature (Tfc), hydrogen and oxygen partial pressure. Referring parameter values of the fuel cell model in Table 1, Figure 5 shows that the maximum cell power output appears when the current is operated around 250A and the cell temperature is fixed at Tfc= 75°C. Moreover, the voltage and power of the stack is given by Vstack= 30Vfc; Pfc= VstackifcAfc.
Remark 1: To address the feasible manipulation of the fuel cell stack, two pressure regulators for manipu-lating the outlet flow rates of hydrogen and oxygen at the anode and cathode, respectively, are required. In addition, the oxygen starvation phenomenon should be avoided, i.e., the following inequality for oxygen excess ratio (λO2),
_mO2;in
8:75ifc=F ≥ λO2 ð26Þ
should be satisfied by increasing the inlet flow rate of oxygen (_mO2;in) or air flow [15].
Remark 2: The stack requires a circulating water sys-tem to keep the relative humidity of membrane as well as regulate the stack temperature. It is assumed that the stack system is isothermal, the relative humidity is kept at a desired level, and the hydrogen flow in the inlet of fuel cell (_mH2;in). In fact, the fuel processing delays, in-cluding reaction time and transportation delay exist such that the power gap between supply and demand is inevitable.
Table 1 PEMFC Parameters
Parameter Value Van 0.005 m 3 kan 0.065 mol s− 1atm− 1 PBPR 1 atm Vca 0.01 m 3 kca 0.065 mol s− 1atm− 1 F 96485 Cmol-1 Afc 232 cm2 lm 178 × 10− 4cm R 8.314 Jmol− 1K− 1 Cdl 0.035 × 232 F λO2 2
Photovoltaic generator
A photovoltaic (PV) generator is composed of numbers of solar cells connected in series and parallel to provide the desired output terminal voltage and current. Using the Kirchoff’s current law the terminal current Isthrough the solar cell is expressed by [3].
Is¼ Iph− Id− Ish ð27Þ
(i) The photocurrent Iphis described as
Iph¼ p1Es 1þ p2ðEs−E0Þ þ p3 Tj−T0
ð28Þ (ii) The diode loss current Idis described as
Id ¼ p4T3j exp − Eg κTj exp e0 afNsκ Vsþ RsIs Tj −1 ð29Þ (iii) The shunt current Ishis shown by
Ish¼
Vsþ RsIs
Rsh ð30Þ
where the cell junction temperature Tjis expressed by
Tj¼ Taþ
Es
800ðTNCOT−20Þ ð31Þ
where P1, P2, and P3 are empirical constants. E0 and
T0 are reference solar radiation and reference junction
temperature, respectively. The P4is an empirical constant,
afis the ideality factor of the PV array, Egis the gap
en-ergy voltage of silicon, κ is Boltzmann’s constant, Vsis
Table 2 PV Parameters Symbol Value T0 298 K TNOTC 316 K E0 1000 W m− 2 κ 1.3854 × 10− 23J K− 1 Eg 1.12 eV p1 2.96 Am2W− 1 p2 − 8.6 × 10− 4 m2W− 1 p3 0.0037 K− 1 p4 1272.3 AK− 3 Rs 1.29Ω Rsh 154.1Ω
the terminal voltage, Nsand Rsare the number of cells in
series and series resistance, and Rsh is the parallel
resist-ance. All the above parameter values for the PV system are shown in Table2. Figure6shows that the maximum power output of the PV system exists at different Taand Es.
Auxiliary devices
The auxiliary devices shown in Figure 1 include a lithium-ion battery which is considered as a high-capacity energy storage to compensate the power gap and share the load demand and several he boost DC/DC converters are used to boost the DC voltage of the units of PV, PEMFC and battery. The dynamic responses of battery are faster than other units in the hybrid power system, in our approach the modeling of battery is omitted and the well-defined charging/discharging mechanism is considered [16,17]. The DC/AC pulse-width modulation (PWM) is used to meet the specification of the household electricity, where the dynamics with regard to AC voltage and current wave-form are shown in Figure 7 using the SimPowerSystems™ toolbox in Matlab.
Scenario analysis
For the proposed HPG system, the solar irradiance, water and ethanol are denoted as energy sources. Assumed that the weather variation is inevitable and the sources of water and ethanol are reliable, the HPG system is considered as
the optimal power generator since the optimized EFC power generator according to optimal operating condi-tions in Figures 4 and 5 is specified and the maximum PV power in Figure 6 is achieved by using the maximum power point tracking (MPPT) controller. Moreover, sce-nario analysis of the daily operation of the HPG system is addressed as follows.
1. Hybrid power dispatch: Figure8(a) shows that the PV and PEMFC systems are dispatched to precisely meet the daily household load demand [3]. In our design, the daily PV power distribution shown in Figure8(b) is fixed according to prescribed patterns of solar irradiance. A scenario shows that both PV and PEMFC are integrated to instantly cope with the peak power. Especially, the EFC power should dominate the main electricity supply during the day and night.
2. Power gap compensation: If the EtOH-to-H2processor
cannot produce pure hydrogen immediately due to slow reactions, then the EFC power decay at this moment. It is caused by the fuel processing delay such that the power demand gap (desired Pfc-actual Pfc)
shown in Figure8(b) appears. Assumed that the rapid response of Li-ion battery can instantly compensate the power demand gap and the battery charging from PV and EFC units is always larger than the battery
discharging, Figure9(a) and9(b) show that the HPG system can precisely meet the daily load demand. In this perfect scenario, the hybrid power dispatching shown in Figure9(a) is confirmed where the battery contribution (green area) aims to compensate the power demand gap during each time period. Figure9 (b) shows that the battery is recharged by the excess power from PV and PEMFC during day and night. Regarding hybrid power dispatching problem, the PV unit (blue bars) provides 34.5% total power, the battery (green bars) is 12.4% and the EFC (red bars) is about 53.1%. Notably, the battery is charged from the EFC is about 56.1% and 43.9% from the PV. It implies that the PV power is used to save 39.9% fuel consumption. System efficiency
The efficiency of the power generation system is usually affected by the electric power, mechanical energy and heat. To ignore the effects of mechanical energy and heat, the efficiency of the HPG system is investigated as follows.
A. Photovoltaic efficiency
According to the formulation of solar cell efficiency limits [18], the PV efficiency is described as ηmax¼
Pmax
EsAs ð32Þ
whereηmaxis the maximum efficiency of the PV system,
Pmax is the maximum PV power, and As is the surface
area of the solar panel. B. EFC efficiency
Referring the experimental data for ethanol
reforming processes [19,20], the energy efficiency of EtOH-to-H2processor is defined as
ηESR¼
_mH2;inHHVH2
_mEtOH;inHHVEtOHþ _mH2O;inHHVH2O
ð33Þ and the energy efficiency of fuel cell is described as
ηfc¼
Pfc
_mH2;inHHVH2
ð34Þ where HHVirepresent the high heating value of species
i. _mEtOH;in and _mH2O;in represent the inlet flow rate of
ethanol and water, respectively. Moreover, the efficiency of the EFC is expressed byηefc=ηesrηfc. Figure10shows
that the energy efficiency of the EFC unit is increasing if the load demand increases, but the energy efficiency of the FC unit without the use of EtOH-to-H2processor
decreases if the load demand is larger than 5 kW. It is verified that the EFC design can ensure higher energy efficiency than the conventional hydrogen fueled fuel cell system.
C. According to above efficiency of each unit, the (overall) system efficiency of HPG system is expressed as
ηoverall¼
PPV þ Pfcþ Pbattery
ηconverterηinverter
PPV=ηmaxþ Pfc=ηefcþ Pbattery=ηbattery
ð35Þ
where ηbattery, ηconverter and ηinverter are efficiencies of
Li-ion battery, DC/DC converter and DC/AC inverter, respectively. The battery power Pbattery is evaluated by
Pd− Pefc− PPV where Pd is set as the load. Referring
the initial efficiency of Li-ion battery [21], we assume ηbattery for a new battery. Referring to references [22,23],
we assume ηconverter =0.9 and ηinverter = 0.98. Referring
the hybrid power dispatching in Figure 9(a), the hy-brid system efficiency by Eq. (35) is shown in Figure 11. Based on the hybrid power system using parallel and series connections, the system efficiency is around 11% during the day, but it reaches over 60% during the night. Obviously, the PV system induces lower system efficiency and it can be significantly improved by using the integrated reformer/fuel cell system and battery.
Conclusions
An optimized fuel processing unit using ethanol fuel can produce high-purity hydrogen. The simulation shows that the stand-alone EtOH-to-H2 processor not only guarantee higher energy efficiency, but also it can continuously produce hydrogen if the fuel is enough. According to scenarios for the daily operation of the HPG system, the EFC power dominates the power supply during the night, the PV system dominates the power supply during the day and the backup battery aims to instantly compensate the power gap and store the excess power from PV or EFC. According to the hybrid power dispatch, the distribution of the HPG system efficiency is specified.
Nomenclature
af, ideality factor
Afc, effective fuel cell area, cm2
As, surface area of the solar panel, m2
CO2, oxygen concentration at the cathode/membrane interface, molm-3
CH2, hydrogen concentration at the anode/membrane interface, molm-3
Cdl, Double layer capacitance, F
E0, Reference solar radiation, W m− 2
Eg, Gap energy voltage for silicon, eV
Es, solar radiation, Wm-2
i, current density, Acm-2 Is, terminal current of PV cell, A
kan, kca, flow constant of anode and cathode, mol s− 1atm− 1
lm, Membrane thickness, cm
cp, specific heat capacity, J K− 1kg− 1
Pi, partial pressure of i component, atm
PBPR, back pressure, atm
P, cell power, W
Ta, ambient temperature, K
T0, reference junction temperature, K
TNCOT, normal cell operating temperature, K
Rs, series resistance,Ω
Rsh, parallel resistance,Ω
u, superficial velocity, m s− 1 Vs, terminal voltage of PV cell, V
η
Figure 11 HPG system efficiency.
Competing interests
The authors declare no competing financial interests.
Authors’ contributions
The energy efficiency of the ethanol-fueled fuel cell (EFC) is higher than the hydrogen-fueled fuel cell system. With the aid of the stand-alone EtOH-to-H2 processor and backup battery. The HPG system efficiency according to hybrid power dispatch is improved. All authors read and approved the final manuscript.
Acknowledgment
The authors would like to thank the National Science Council of the Republic of China for financially supporting this research under Contract No. NSC 100-2211-E-006-264.
Author details
1Department of Chemical Engineering, National Cheng Kung University,
Tainan 70101, Taiwan.2National Yunlin University of Science and Technology, Douliou, Yunlin 64002, Taiwan.
Received: 27 November 2013 Accepted: 14 February 2014 Published: 4 March 2014
References
1. Muselli M, Notton G, Louche A: Design of hybrid-photovoltaic power generator, with optimization of energy management. Sol Energy 1999, 65:143–157.
2. Elhadidy MA: Performance evaluation of hybrid (wind/solar/diesel) power systems. Renew Energy 2002, 26:401–413.
3. Hwang JJ, Lai LK, Wu W, Chang WE: Dynamic modeling of a photovoltaic hydrogen fuel cell hybrid system. Int J Hydrogen Energy 2009, 34:9531–9542. 4. Uzunoglu M, Onar OC, Alam MS: Modeling, control and simulation of a
PV/FC/UC based hybrid power generation system for stand-alone applications. Renew Energy 2009, 34:509–520.
5. Zervas PL, Sarimveis H, Palyvos JA, Markatos NCG: Model-based optimal control of a hybrid power generation system consisting of photovoltaic arrays and fuel cells. J Power Sources 2008, 181:327–338.
6. Yilanci A, Dincer I, Ozturk HK: A review on solar-hydrogen/fuel cell hybrid energy systems for stationary applications. Prog Energy Combust Sci 2009, 35:231–244.
7. Gupta RB: Hydrogen Fuel: Production, Transport, and Storage. USA: CPC press; 2009.
8. Shekhawat D, Spivey JJ, Berry DA: Fuel Cells: Technologies for Fuel Processing. UK: Elsevier; 2007.
9. Wu W, Tungpanututh C, Yang HT: A conceptual design of a stand-alone hydrogen production system with low carbon dioxide emissions. Int J Hydrogen Energy 2012, 37:10145–10155.
10. Garcia VM, Lopez E, Serra M, Llorca J: Dynamic modeling of a three-stage low-temperature ethanol reformer for fuel cell application. J Power Sources 2009, 192:208–215.
11. Degliuomini LN, Biset S, Luppi P, Basualdo MS: A rigorous computational model for hydrogen production from bio-ethanol to feed a fuel cell stack. Int J Hydrogen Energy 2012, 37:3108–3129.
12. Uriza I, Arzamendi G, Lopez E, Llorca J, Gandia LM: Computational fluid dynamics simulation of ethanol steam reforming in catalytic wall microchannel. Chem Eng J 2011, 167:603–609.
13. Choi Y, Stenger HG: Water gas shift reaction kinetics and reactor modeling for fuel cell grade hydrogen. J Power Sources 2003, 124:432–439. 14. Khan MJ, Iqbal MT: Analysis of a small wind-hydrogen stand-alone hybrid
energy system. Appl Energy 2009, 86:2429–2442.
15. Wu W, Xu JP, Hwang JJ: Multi-loop nonlinear predictive control scheme for a simplistic hybrid energy system. Int J Hydrogen Energy 2009, 34:3953–3964.
16. Knauff M, McLaughlin J, Dafis C: Simulink model of a lithium-ion battery for the hybrid power system test-bed, ASNE Intelligent Ships Symposium, Philadelphia, PA, USA; 2007.
17. Erdinc O, Vural B, Uzunoglu M: A dynamic lithium-ion battery model considering the effects of temperature and capacity fading, 2nd International Conference on Clean Electrical Power, Capri, Italy; 2009.
18. Nelson J: The Physics of Solar Cell. UK: Imperial College Press; 2003.
19. Deluga GA, Salge JR, Schmidt LD, Verykios XE: Renewable hydrogen from ethanol by autothermal reforming. Science 2004, 303:933–937.
20. Hung CC, Chen SL, Liao YK, Chen CH, Wang JH: Oxidative steam reforming of ethanol for hydrogen production on M/Al2O3. Int J Hydrogen Energy 2012, 37:4955–4966.
21. Shen J, Tang Y, Liang Y, Tan X: Relationship between initial efficiency and structure parameters of carbon anode material for Li-ion battery. J Cent South Univ Technol 2008, 15:484–487.
22. Ma D, Ki WH, Tsui CY, Mok PKT: A single inductor dual-output integrated dc/dc boost converter for variable voltage scheduling, Proceeding of the ASP-DAC, Asia and South Pacific; 2001.
23. Anis RA: Stepped sine wave DC/AC inverter I. Theoretical analysis. Energy Mater Sol Cells 1992, 28:123–130.
doi:10.1186/2043-7129-2-5
Cite this article as: Wu et al.: Scenario analysis of a bioethanol fueled hybrid power generation system. Sustainable Chemical Processes 2014 2:5.
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