Fuel cells and hydrogen energy systems

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Fuel Cell and Hydrogen Energy Systems Loh Kee Shyuan Puri Pujangga Universiti Kebangsaan Malaysia (UKM) National University of Malaysia 18 June 2014 7 th Asian School on Renewable Energy Fuel Cell Institute, UKM

Transcript of Fuel cells and hydrogen energy systems

Page 1: Fuel cells and hydrogen energy systems

Fuel Cell and Hydrogen Energy Systems

Loh Kee Shyuan

Puri Pujangga Universiti Kebangsaan Malaysia (UKM)

National University of Malaysia 18 June 2014

7th Asian School on Renewable Energy

Fuel Cell Institute, UKM

Page 2: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Outline

• Introduction

• Types of fuel cells and hydrogen production systems

• Basic performance and cost

• Applications

• Future prospects

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Chronology of Fuel Cell Development

• 1839 - Sir William Grove, first electrochemical H2/O2 reaction to generate energy

• 1950s - GE developed the solid-ion exchange H2 fuel cell used by NASA

• 1960s- GE produced the fuel cell-based electrical power system for NASA Gemini and Apollo space capsules

• 1960s other fuel cells discovered – phosphoric acid, SOFC, molten carbonate

• 1970s – Vehicle manufacturers began to experiment FCEV.

• 1990 – The California Air Resource Board introduced the Zero Emission Vehicle (ZEV) Mandate.

• 2000 – Fuel cell buses were deployed as part of the HyFleet/CUTE project

• 2007 – fuel cell started to be sold commercially as APU

• 2008 – Honda begins leasing the FCX fuel cell electric vehicle.

• 2009 – Large scale of residential CHP programme in Japan.

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Page 5: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

What is Fuel Cell?

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Page 6: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

How does fuel cell work?

• In a typical fuel cell, gas (hydrogen) is fed continuously to the anode compartment and an oxidant (e.g. oxygen from the air) is fed continuously to the cathode (positive electrode) compartment. Electrochemical reactions take place at the electrodes to produce electric current.

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Page 7: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

How does fuel cell work?

• At the anode:

H2 2H+ + 2e-

• At the cathode:

½ O2 + 2H+ + 2e- H2O

• Overall:

H2 + ½ O2 H2O

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Page 8: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Main Components

• Electrode: a thin catalyst layer pressed between the ionomer membrane and porous, electrically conductive substrate.

• Electrolyte: A chemical compound that conducts ions from one electrode to the other inside a fuel cell.

• Catalyst: A substance that causes or speeds a chemical reaction without itself being affected.

• Bipolar plates: connecting the anode of one cell to the cathode of the adjacent cell.

• Gas diffusion layer: a layer between the catalyst layer and bipolar plates, also called electrode substrate or diffusor/current collector.

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Main Components

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Endplate

Bipolar plate

Page 10: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Schematic overview of the three phase boundary

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell vs Battery

• Converting chemical energy to electrical energy.

• Works like a battery but does not run down or need recharging.

• Produce electricity as long as fuel is supplied.

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Comparison of Fuel Cells with Internal Combustion Engines

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Chemical energy of fuels Electrical Energy

Thermal Energy Mechanical Energy

Fuel Cell

ICE-1

ICE-2

ICE-3

Schematic of energy conversion in Fuel cells and Internal

Combustion Engines (ICE)

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell as Power Alternative

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ICEs - operate by burning fuel to create heat, heat is converted into

mechanical energy and then electric power. - the efficiency of this conversion process is greatly affected by

losses of waste heat and friction. - In contrast, fuel cells efficiently convert fuel directly into

electricity via an electrochemical reaction - Like an ICE, fuel cells conveniently use fuel from and they

operate continuously as long as fuel is supplied. - However, fuel cells do not burn fuel and therefore do not

produce the air pollutants resulting from combustion.

Batteries - energy storage devices; they can only produce power

intermittently as they must be recharged. - recharging process is lengthy, inconvenient, and shifts pollution,

efficiency and cost issues up the power line to central electrical power plants.

- Batteries and fuel cells are both electrochemical (no combustion) devices that have high efficiency and quiet operation.

- A battery stores its energy in its electrodes. Electricity is released as the stored energy is consumed.

Page 14: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

High energy-conversion efficiency

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Thermodynamic efficency for fuel cells and Carnot efficiency for heat

engines.

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Overview of fuel cell types

• They are usually differentiated by the type of fuel used, operating pressure and temperature, area of application.

• Fuel cells can be distinguished by the type of electrolyte material used as a medium for the internal transfer of ions (protons).

• The type of electrolyte determines the operating temperature on which the type of catalyst depends.

• The choice of fuel and oxidant for any FC depends on their electrochemical activity, cost, and easiness of fuel and oxidant delivery and removal of reaction by-products.

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Overview of fuel cell types

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Fuel Cell Electrolyte Qualified Power (W)

Working Temperature

(◦C)

Electrical Efficiency

Status

Alkaline fuel cell Aqueous alkaline solution (e.g., potassium hydroxide)

10 kW to 100 kW

60-120 35-55 Commercial/Research

Direct methanol fuel cell

Polymer membrane (ionomer)

100 kW to 1 mW

60-200 20-30 Commercial/Research

Phosphoric acid fuel cell

Molten phosphoric acid (H3PO4)

up to 10 MW 150-220 40 Commercial/Research

Molten carbonate fuel

cell

Molten alkaline carbonate (e.g., sodium bicarbonate

NaHCO3)

100 MW 600-650 >50 Commercial/Research

Solid oxide fuel cell

O2-

-conducting ceramic oxide (e.g., zirconium dioxide,

ZrO2)

up to 100 MW

700–1000 >50 Commercial/Research

Proton exchange membrane fuel

cell

Polymer membrane (ionomer) (e.g., Nafion® or Polybenzimidazole fiber)

100 W to 500 kW

50-100 35-45 Commercial/Research

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Characteristics of Fuel Cells

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Fuel Cells Attractive Attributes Undesirable Attributes

Phosphoric Acid Fuel Cell (PAFC).

-Low temperatures suitable for portable device applications -Ability for variable power output -Broad fuel choice

-Uses expensive platinum as a catalyst. -Electrolyte is poor conductor at low temperatures

Proton Exchange Membrane Fuel Cell

(PEM).

-Low operating temperature suitable for transportation and portable devices -High power density

-Uses expensive platinum as a catalyst -Sensitivity to fuel impurities

Molten Carbonate Fuel Cell (MCFC)

-High operating temperature improves efficiency for base load power plants.

-Not suitable for small-sized applications

Solid Oxide Fuel Cell (SOFC)

-High operating temperature improves efficiency for base load power plants. -Solid electrolyte improves conductivity

- Electrolyte is made from ceramics and solid zirconium oxide that is a rare mineral

Alkaline Fuel Cells (AFC)

-Low temperature and high fuel-to-electricity efficiency

-Requirement of pure hydrogen and allergic to carbon dioxide

Direct Methanol Fuel Cells (DMFC).

-Eliminates need for fuel reformer drawing hydrogen directly from the anode -Low temperatures suitable for portable devices

-Fuel crossing from anode to cathode without producing electricity

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel cell Basic Chemistry & Thermodynamics

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel cell Basic Chemistry & Thermodynamics

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T (K) ΔH ΔG ΔS Eth (V)

298.15 -286.02 -237.34 -0.16328 1.23

333.15 -284.85 -231.63 -0.15975 1.20

353.15 -284.18 -228.42 -0.15791 1.184

373.15 -283.52 -225.24 -0.15617 1.167

Change of enthalpy, Gibbs Free Energy, and Entropy of hydrogen/oxygen fuel cell reaction with temperature and resulting theoretical cell potential

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel cell Basic Chemistry & Thermodynamics

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• Effect of pressure

For the H2/O2 fuel cell reaction, the Nernst equation becomes:

By introducing Eq (1),

Therefore, cell potential is higher at higher reactant pressures.

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Electrochemistry • Electrode kinetics

Electrochemical reactions involve transfer of electrical charge and change of Gibbs energy.

The rate of electrochemical reaction is determined by an activation energy barrier that the charge overcome in moving from electrolyte to electrode or vice versa.

Faraday’s Law: current density is proportional to the charge transferred and the consumption of reactant per unit area:

i = nFj

The consumption of the reactant species is proportional to their surface concentration. For the forward reaction, the flux is:

jf =kfCOx and jb = kbCRd

The net current generated is the difference between the electrons released and consumed:

i =nF (kfCOx − kbCRd)

At equilibrium, the net current should equal zero because the reaction will proceed in both directions simultaneously at the same rate.

The rate which reaction proceed at equilibrium is called the exchange current density.

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Page 24: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Electrochemistry

• Exchange current density – The exchange current density is analogous to the rate constant chemical

reaction.

– i0 is concentration dependent, is a function of temperature, also a function of catalyst loading and catalyst specific surface area.

– The effective exchange current density at any temperature and pressure is given as:

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ref

c

ref

r

ccref

T

T

RT

E

PLaii 1exp

Pr

00

Where

i0ref = reference exchange current density (at

ref T, P) per unit catalyst surface are, Acm-2

Pt.

ac = catalyst specific area.

Lc = catalyst loading.

Pr = reactant partial pressure, kPa.

Prref = reference pressure, kPa.

γ = pressure coefficient (0.5 to1.0).

Ec = activation energy (66 kJ/mol for O2

reduction on Pt).

R = gas constant, 8.314 Jmol-1K-1

T = temperature, K.

Tref = reference temperatire. 298.15 K

Page 25: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Electrochemistry

• Voltage Losses

Activation polarization

Internal Currents and crossovers losses

Ohmic (resistive) losses

Concentration polarization

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Page 26: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Electrochemistry

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• Voltage different from equilibrium is need to get the electrochemical reaction going – activation polarization

aacc

rcell

aactcactraccell

i

i

F

RT

i

i

F

RTEE

VVEEEE

,0,0

,,

lnln

• each H2 molecule that diffuse results in fewer electrons that travel to the external circuit

• the losses are minor during fuel cell operation, BUT significant when fuel cell operates at low current densities, or it is at open circuit voltage.

0

, lni

i

F

RTEE

lossrOCVcell

Page 27: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Electrochemistry

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• Ohmic losses occur due to the resistance of the flow of ions in the electrolyte and resistance to the flow of electrons.

• Concentration polarization occur when a reactant is rapidly consumed at the electrode by the electrochemical reaction so that concentration gradients are established.

cieiiii RRRR ,,,

ii

i

nF

RTV

L

Lconc ln

Page 28: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Electrochemistry

• Three types of losses in fuel cell.

• Activation losses are by far the largest losses at any current density.

• The cell voltage is therefore:

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ohmcconcactaconcactrcell VVVVVEV )()(

i

aL

aL

cL

cL

aoacoc

PTrcell iRii

i

nF

RT

ii

i

nF

RT

i

i

F

RT

i

i

F

RTEE

)ln()ln()ln()ln(

,

,

,

,

,,

,,

Page 29: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Polarization Curve • A polarization curve is the most important characteristic of a fuel

cell and its performance.

• It would be useful to see what effect each of the parameters has on the polarization curve shape.

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Sensitivity of parameters in polarization curve

• Effect of transfer coefficient/Tafel slope

• Effect of exchange current density

• Effect of H2 crossover and internal current loss

• Effect of internal resistance

• Effect of limiting current density

• Effect of operating pressure

• Air vs oxygen

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Page 31: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Sensitivity of parameters in polarization curve

Effect of transfer coefficient on fuel cell performance

α =0.5

α =1.5

α=1

Effect of exchange current density on fuel cell polarization curve.

Effect of cell internal resistance on its polarization curve.

Effect of operating pressure on fuel cell polarization curve

Page 32: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Theoretical Fuel Cell Efficiency

• Assuming that all of the Gibbs free energy can be converted into electrical energy, the maximum possible efficiency of a fuel cell is:

η= ΔG/ ΔH = 237.34/ 286.02 = 83%

• Maximum theoretical fuel cell efficiency:

η= ΔG/ ΔHLHV = 228.74/ 241.98 = 94.5%

• If both ΔG/ ΔH are divided by nF, the fuel cell efficiency may be expressed as a ratio of two potentials:

η= (ΔG/nF)/ (ΔH/nF)HHV = 1.23/1.482 = 0.83

• The fuel cell efficiency is always proportional to the cell potential.

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Page 33: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Basic performance of fuel cell

• The overall performance of fuel cell may be evaluated on the basis of the current-voltage diagram.

Journal of Power Sources 113 (2003) 37–43

Effect of cell temperature on performance. E-TEK 20% Pt/C; Pt =0:12 mg/cm2.

Page 34: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Basic performance of fuel cell

Journal of Power Sources 113 (2003) 37–43

Effect of Pt loading on performance for electrodes made using E-TEK 20% Pt/C, 35/45/45 ˚C.

Page 35: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Implication and Use of Fuel Cell Polarization Curve

• Fuel cell polarization curve may be used for diagnostic purposes, as well as for sizing and control of a fuel cell.

• From potential-current relationship, other information about the fuel cell may also become available just by rearranging the potential-current data.

Page 36: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Use of polarization curve for fuel cell sizing

• H2/air fuel cell polarization curve is given with the followings parameters:

α = 1, i0 = 0.001 mAcm-2, Ri = 0.2Ωcm-2

Operating conditions: T =60˚C, P=101.3 kPa

Operating point is selected at 0.6 V. Active area is 100 cm2.

(a) Calculate nominal power output.

Page 37: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Solution

• Power output is Wel = Vcell x i x A Vcell = 0.6 V A =100 cm2

i = ??? • Current density must be determined from the polarization curve. Because no H2 crossover and

internal current losses and no limiting current are given, the fuel cell polarization curve may b calculated from:

Where Er = 1.482-0.000845T + 0.0000431T ln(PH2PO2

0.5) = 1.482-0.000845 (333.15) + 0.0000431 (333.15) ln (0.21)0.5 =1.189 V

R=8.314 Jmol-1K-1

T=333.15K α =1 n = 2 F =96485 C mol-1

Io = 0.001 mAcm-2

Ri = 0.2 Ωcm2

Current cannot be explicitly calculated from the previous equation.

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Page 38: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Solution ( b) The engineers improved fuel cell performance by improving internal

resistance to Ri = 0.15 Ohm-cm2.calculate power gain at 0.6 V

• From the new polarization curve, the current density is:

I = 1.25 Acm-2

Power output is, Wel = 0.6 x 1.25 x 100 = 75.0 W

Power gain is ΔW = 75.0 – 58.2 = 16.8 W or 28.9%

Page 39: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Solution

(c) The engineer found out that there was not enough air flow to operate

this fuel cell at a higher current density. Calculate the power and efficiency gain if the improved fuel cell is to be operated at the original current density.

Vcell = 1.189 – (8.314x333.15)/(1x96485) ln (970/0.001) – 0.97 x 0.15

= 0.648 V

New power output is, Wel = 0.648 x 0.97 x 100 = 62.9 W

Power gain is, ΔW 62.9 -58.2 = 4.7 W or 8%

The efficiency before improvement was:

η=Vcell/1.482 = 0.6/1.482 =0.405

The efficiency after improvement is:

η=Vcell/1.482 =0.648/1.482 = 0.437

Page 40: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Solution

Fuel cell power output is 58.2 = Vcell x i x 100 Another Vcell-i relationship is obtained from

the polarization curve: Vcell = 1.189 – (8.314x333.15)/(1x96485) ln

(i/0.001) – i x 0.15 Again, by iteration or graphically the solution

is: Vcell = 0.666 V i = 875 mACm-2

Noted that point “a” and “d” lay on two different polarization curve but in the same constant power line.

The new efficiency is η = Vcell/1.482 = 0.666/1.482 = 0.449

(d) The engineer realized that there is no need for additional power. Calculate the efficiency gain if the improved fuel cell is to be operated at the original power output.

Page 41: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Cost expectations-Fuel cell costs

• The US Department of Energy (DOE) had aimed (in 2007) to demonstrate fossil fuelled PEMFC CHP systems for under $750/kW by 2011 and under $450/kW by 2020.

• These targets were recently revised to $1200/kW by 2015 and $1000/kW by 2020, for a complete 2 kW natural gas fuelled PEMFC system.

• The DOE’s SECA programme established cost targets for 3-10 kW stationary SOFC systems, initially starting at $800/kW by 2005, then falling to $700/kW by 2008 and $400/kW by 2010.

• Their cost reduction efforts now aim to demonstrate fuel cell stacks for $175/kW and complete systems for $700/kW

Page 42: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Page 44: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

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Page 46: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Type of fuel cells application?

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There are many different uses of fuel cells being utilized right now. Some of these uses are…

•Power sources for vehicles such as cars, trucks, buses and even boats and submarines •Power sources for spacecraft, remote weather stations and military technology •Batteries for electronics such as laptops and smart phones •Sources for uninterruptable power supplies.

Page 47: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Type of fuel cells application?

Page 48: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel cell vehicles by various automakers

Page 49: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Layout of Honda FCX Powertrain

Page 50: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Specification of several fuel cell vehicles

Page 51: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen stations

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Toyota FCHV-BUS at FC Expo

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•90 kW PEFC Fuel cell stack: twice •Motor: AC synchronous 80 kW twice •Hydrogen tank: Compressed hydrogen gas 35 MPa / 150 liter, five (version 2002) or seven (version 2005) •Passenger capacity: 63 (included 22 seats)

Page 53: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Residential Fuel Cell

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Page 54: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Fuel Cell Technologies Forging Cross-industry Collaboration

• Google, one of the pilot customers, has a 400-kilowatt installation at its main campus. Over 18 months, the project delivered 3.8 million kilowatt hours of electricity.

• Wal-Mart has installed two 400 KW systems at retail locations in Southern California.

• Bank of America is putting in a 500 KW installation at a call center in Southern California.

• Coke too is putting in a 500 KW installation, at its Odwalla plant in Dinuba, Calif. That fuel cell will run on re-directed biogas and provide up to 30 percent of the plant’s electricity needs.

• Cox Enterprises is putting in a 400 KW installation at its KTVU TV station in Oakland, Calif.

• E-commerce giant e-Bay is using a 500 KW installation at its San Jose, Calif., facility that will run on biogas.

• FedEx has installed five 100 KW Bloom boxes at its package sorting facility in Oakland.

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Alternative Energy

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• Increasing of energy demand

• Depletion of fossil fuel in near future

• Reducing negative impact on environmental

Renewable Energy 31 (2006) 719–727

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Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

What is our choices?

• Pressing need to find alternative renewable, sustainable and clean energy source.

Page 58: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Alternative energy

• Sustainable – ability of an energy source to continue providing energy for a long period of time

• Renewable – energy that comes from resources which are continually replenished

• Clean ‐ does not pollute the atmosphere when used/produced

Page 59: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen properties

• Gaseous, odorless, colorless, tasteless, flammable, explosive

• Bonds with many other elements

• Seldom found in pure form in nature

• Liquid at -253 ˚C (20 K)

• Not an energy source, it is an energy carrier/store

Page 60: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen safety

• Hydrogen Vehicle Safety.

– The Ford Motor Company, in their report to the US Department of Energy included this statement:

“Overall, we judge the safety of a hydrogen FCV system to be potentially better than the demonstrated safety record of gasoline or propane, and equal to or better than that of natural gas.”

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Page 61: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen safety

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Hydrogen Vehicle Gasoline Vehicle Hydrogen Vehicle Gasoline Vehicle Hydrogen Vehicle Gasoline Vehicle

One minute after ignition; hydrogen fire nearly extinguished

The pictures below were taken 3 seconds after ignition

The following pictures compare hydrogen and gasoline fires from an experiment conducted at the University of Miami.

The car on the left contained high pressure hydrogen tanks with 175,000 btu of energy and the car on the right had a conventional gasoline tank with just five pints of gasoline or about 70,000 btus of energy. Spark plugs were installed outside both vehicles to ignite a leaking hydrogen tank and a leaking gasoline line.

Page 62: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen Production Paths

62

Page 63: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen production methods

• Main methods

-Thermal

-Electrochemical

-Biological

• Others

-Chemical reaction

-etc

Primary method Process Source/Feed stock

Energy

Thermal Stream reforming

Natural gas

High temperature steam (autothermal)

Thermochemical water splitting

Water High temperature heat from nuclear reactor

Gasification Coal, Biomass High temperature (& pressure) steam & oxygen

Pyrolysis Biomass Moderately high temeprature

Electrochemcal Electrolysis Water Electricity from solar, wind, hydro & nuclear

Photoelectrochemical

Water Direct from sunlight

Biological Photobiological Water & algae strains

Direct sunlight

Anaerobic/ferm entation

Biomass & microorganism

Food source

Anaerobic degistion

Biomass High temperature heat

Fermentative microorganisms

Biomass High temperature heat

Page 64: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen production technologies

Steam methane reforming : • widely used in the chemical and refining industries.

• Considered the cheapest way of producing hydrogen.

• Reforming involves the reaction of desulphurized natural gas with high-temperature steam over a Ni-based catalyst.

• This produces syngas-mainly a mixture of H2 and CO.

• The CO is then converted to H2 and CO2 via a water gas shift reaction.

• High purity (up to 99.99%) H2 is separated using pressure swing adsorption method.

Page 65: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen production technologies

Coal gasification:

• well-established commercial technology

• competitive with SMR only where oil and/or natural gas are expensive.

• coal could replace natural gas and oil as the primary feedstock for hydrogen production, since it is so plentiful in the world.

Page 66: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen production technologies

Electrolysis of water : • Water molecules can be separated using electricity. But we use

electricity to produce hydrogen to produce electricity again.

• Pure water is in many places a scarce resource.

• The electricity for the electrolysis needs to be produced and the water needs to be purified (soft de-ionized water is needed).

• Reaction:

• Electricity can be obtained at a large scale from nuclear reactors but the hydrogen needs to be stored and transported, and nuclear fuel is not a renewable source of energy.

• At a VERY small scale wind or solar power can be used, but this energy is available only when there is wind or sunlight.

Page 67: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen production technologies

Biomass gasification and pyrolysis: • Provide two ways to produce H2 from biomass. • The processes can be adapted to a range of feedstock:

switch grass, plant scraps, garbage, willow, sugar cane waste.

• Both techniques are followed by a reforming stage. • Gasifier may be heated indirectly and directly. • With pyrolysis, biomass is rapidly heated in the absence

of O2, the vapors are then condensed to form pyrolysis oil.

• This pyrolysis oil can be used as feedstock for H2 production.

Page 68: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Conversion of Biomass

Pyrolysis

Gasification

Combustion

No oxygen

With oxygen (partial oxidation)

With oxygen (complete oxidation)

Organic material + heat -> charcoal +oil +gases

Organic material + O2 +H2O-> H2 +CO2 +CO+ others

Organic material + O2-> CO2 +H2O

Slow &Low (<450ºC) -Max char 35%wt Intermediate (450-500ºC) -Typical 10-15% has. 20-30% char, 45-65% oil Fast & high (>500ºC) -(>550ºC – mas oil 70%) -(>600ºC - max gas 80%)

High (>800ºC)

Low (start 200‐300ºC) (>1000ºC)

Gas-Syngas CO2

H2O CO CH4 etc

Heat

Solid-char

Liquid-oil

Hydrogen

Transfrom

Page 69: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen Storage Alternatives

• Compressed Gas Storage

• Solid State Storage

• Liquid Hydrogen Storage

Page 70: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Compressed Gas Storage

Page 71: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

High Pressure Gas

• High-pressure hydrogen is stored in cylinders.

• Conventional cylinders – cylindrical shaped sidewall section with hemispherical end domes.

• Conformal Cylinders – Use multiple cylinders in tandem and distort the cylindrical shape in order to increase the usable volume.

Page 72: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Hydrogen Cylinders

Page 73: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Metal Hydrides

• Principle used is that some metals readily absorb gaseous hydrogen under conditions of high pressure and moderate temperature to form metal hydrides

• These metal hydrides release the hydrogen gas when heated at low pressure and relatively high temperature

Page 74: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Metal Hydrides

• There are many types of specific metal hydrides

• Primarily they are based on metal alloys of magnesium, nickel, iron and titanium

• They are divided into:

• high hydrogen desorption temperature

• low hydrogen desorption temperature

Page 75: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Metal Hydrides

• High hydrogen desorption temperature

• Less expensive

• Holds more hydrogen

• Requires significant amount of heat to release hydrogen

• Low hydrogen desorption temperature

• Heat from an engine is sufficient to release hydrogen

• Sometime in this case it releases hydrogen at ambient temperatures

• It needs to be pressurized to overcome this problem

Page 76: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Metal Hydrides

Page 77: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Metal Hydrides

Advantages

• Hydrogen becomes part of the chemical structure of the metal itself and therefore does not require high pressures or cryogenic temperatures for operation

• Since hydrogen is released from the hydride for use at low pressure, hydrides are the most intrinsically safe of all methods of storing hydrogen

Page 78: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Metal Hydrides

Disadvantages • They have low mass energy density

• Best metal hydrides contain only 8% hydrogen by weight

• very heavy and expensive • Metal hydride storage systems can be up to 30

times heavier and ten times larger than a gasoline tank with the same energy content

• They must be charged with only very pure hydrogen • If they become contaminated there is loss of

capacity

Page 79: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Liquid Hydrogen Storage

Liquid hydrogen storage tank (850,000 gallons) at NASA KSC

Page 80: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Liquid Hydrogen

• The storage of liquefied cryogenic gases is a proven and tested technology.

• Hydrogen was first liquefied by J. Dewar in 1898.

• In liquid form, hydrogen can only be stored under cryogenic temperatures.

Page 81: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Advantages

• Liquid hydrogen: high energy/mass ratio, three times that of gasoline.

• It is the most energy dense fuel in use (excluding nuclear reactions fuels), which is why it is employed in all space programs

• Compared with compressed hydrogen, liquid hydrogen has much lower storage pressure the risk caused by high pressure may be reduced to some extent.

• Liquid hydrogen (LH2) tanks can store more hydrogen in a given volume than compressed gas tanks.

Page 82: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Disadvantages

• Requires extremely low temperatures of -423 F/-2520C.

• Boil-off losses / vaporization of hydrogen due to heat leakage constitute a major disadvantage.

• A highly sophisticated and expensive production and processing system is necessary in order to minimize losses caused by diffusion, evaporation and impurity.

• Evaporation losses on todays tank installations are between 0.3 and 3% per day.

Page 83: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Summary of H2 Storage

Page 84: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Cost expectations-Hydrogen production costs

• H2 production from natural gas by steam reforming methods is well established.

• At low (pipeline) pressure, it is about 1.0 US$kg-1 (based on inexpensive natural gas, assumed at 1.5 US$ GJ-1).

• Simbeck and Chang (2002) estimate the delivered H2 cost from biomass waste is about 2.5 US$kg-1.

• Conventional small-scale electrolyzer H2 cost have been estimated as 8-12 US$kg-1.

• Larger unit using surplus wind power may attain a cost down to 2 US$kg-1

• The H2 cost based on coal gasification is estimated as over 12 US$kg-1

Page 85: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Cost and performance characteristics of various hydrogen production

Process Energy Required

(kWh/Nm3) Ideal

Energy Required (kWh/Nm3)

Practical Status of Tech.

Efficiency [%]

Costs Relative to SMR

Steam methane reforming (SMR)

0.78 2-2.5 mature 70-80 1

Methane/ NG pyrolysis R&D to mature 72-54 0.9 H2S methane reforming 1.5 - R&D 50 <1

Landfill gas dry reformation R&D 47-58 ~1

Partial oxidation of heavy oil 0.94 4.9 mature 70 1.8

Naphtha reforming mature

Steam reforming of waste oil R&D 75 <1

Coal gasification (TEXACO) 1.01 8.6 mature 60 1.4-2.6 Partial oxidation of coal mature 55

Steam-iron process R&D 46 1.9 Chloralkali electrolysis mature by-product

Grid electrolysis of water 3.54 4.9 R&D 27 3-10 Solar & PV-electrolysis of

water R&D to mature 10 >3

High-temp. electrolysis of water

R&D 48 2.2

Thermochemical water splitting

early R&D 35-45 6

Biomass gasification R&D 45-50 2.0-2.4 Photobiological early R&D <1

Photolysis of water early R&D <10 Photoelectrochemical

decomp. of water early R&D

Photocatalytic decomp. of water

early R&D

Page 86: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Cost of various hydrogen production technologies

Technology Cost range (US$ (2000)/GJH2

Additional cost of CO2 capture

Comments

SMR, large-scale (>1000MW) SMR, small-scale (<5MW)

5.25-7.26 11.50-40.40

$7.26 cost increases to $8.59/GJ with CCS Prohibitive

Cost highly dependent on natural gas prices. Transitional technology. Cost highly dependent on natural has prices, plant size and purity of H2 required.

Coal gastification 5.4-6.8 Average of 11% Coal price more stable and predicatable than natural gas.

Biomass gasification (>10MW)

7.54-32.61 (av.14.31)

Not given (with CCS technology, would become carbon negative)

Size ranges from 25 to 303 MW and affects cost.

Page 87: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Cost of various hydrogen production technologies

Technology Cost range (US$

(2000)/GJH2 Additional cost of CO2 capture

Comments

Biomass pyrolysis (>10MW)

6.19-14.98 Not given (with CCS technology would become carbon negative)

Size ranges form 36 to 150MW; cost redued by sale of co-products

Electrolysis, Large scale (>1MW)

11-75 Emissions (and CCS options) depend on source of electricity

Size ranges from 2 to 376MW, but little effect on cost; cost very dependent on assumed price of electricity

Electrolysis, small-scale (<1MW)

28-133 Emissions (and CCS options) depend on source of electricity

Size ranges from 0.03 to 0.79MW, cost very size-dependent.

Page 88: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Wind/ Hydrogen Projects

• Greece RES2H2 Project

• Spain RES2H2 Project ITHER Project

• Canada Ramea Island Prince Edward Island

• United Kingdom HARI Project PURE Project

• United Stated Basin electric, Wind-to-Hydrogen Energy Pilot Project National RE Lab and Xcel Energy, Wind-to-Hydrogen Project

Page 89: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

PURE Project

• The project aims to demonstrate how wind power and hydrogen technology can be combined to meet the energy needs of a remote rural industrial estate.

• PURE was conceived to test and demonstrate safe and effective long-term use and storage of hydrogen produced by renewable energy using wind-powered electrolysis of water, and to regenerate the stored energy into electric energy with a fuel cell.

• The key components of the system are: Wind turbines: Two 15 kW (Proven Ltd) Electrolyzer: 15 kW alkaline operating at 55 bar (AccaGen SA) Hydrogen storage: 44 Nm3 in H2 cylinders PEM fuel cell: 5 kW (Plug Power).

• The electrolyzer section consists of an AccaGen electrolyzer unit assembled with advanced cells specifically designed and manufactured by AccaGen SA for wind application, capable of operating up to 55 bar.

Page 90: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Basin Electric, Wind-to-Hydrogen Energy Pilot Project

• this project was to research the application of hydrogen production from wind energy, allowing for continued wind energy development in remote wind-rich areas and mitigating the necessity for electrical transmission expansion.

• The report completed on August 2005 found that the proposed hydrogen production system would produce between 8,000 kg and 20,000 kg of hydrogen annually.

• The cost of the hydrogen produced ranged from $20 to $10 per kilogram.

• The hydrogen-production system utilizes a bipolar alkaline electrolyzer nominally capable of producing 30 Nm3/h (2.7 kg/h).

Page 91: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Future energy landscape

91

Page 92: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

Furture Energy Landscape

Page 93: Fuel cells and hydrogen energy systems

Loh Kee Shyuan

7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014 93

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