Transcript Hydrogen pipeline versus power line

Small-Scale Wind for
Hydrogen Production for
Rural Power Supplies:
HyLink System
at Totara Valley
MUCER Energy Postgraduate Conference
Wellington 3-5 June 2008
presented by Peter Sudol (Massey University)
Totara Valley
• Demonstration site for
Massey University and
Industrial Research Limited
on distributed generation
Aims:
- design a renewable hybrid
micro-power system at the
end of 11 kV distribution
line
- provide network support
Demonstration on
hydrogen as a means of
balancing and transporting
the fluctuating wind power
System implementation
by IRL
System analysis by Massey
University
Massey University’s 2.2 kW
wind turbine incl. control
system will be used in
conjunction with a larger
electrolyser currently being
developed at IRL.
HyLink System
Characteristic
HyLink System
Power Line
Initial cost
incl. labour
NZ$55,000
- current configuration
- incl. pipeline mole ploughing
NZ$60,000 NZ$100,000
Cost of
conversion devices
NZ$17,000
2 x NZ$2,500
- electrolysis setup
- step up and step down
transformers
NZ$16,000
- underground wiring requires a trench
- overhead wiring complicated due to
difficult terrain
- fuel cell system
Energy loss at
conversion
devices
ηe/conv = 60%
2 x 200 W power loss
- converter/electrolyser subsystem
- power consumption at both
transformers
Lifetime
50 years
ηpemfc/inv = 35% (electr.)
- fuel cell/inverter subsystem
60 years
- MDPE gas pipeline
4,000 operational hrs
- ReliOn PEM fuel cell
10,000 operational hrs
- PEM electrolyser
Energy Storage
Hydrogen pipeline/tank
Batteries
- easy to scale up
- expensive for large-scale storage
Hylink in the IRL Laboratory
Hydrogen was stored in 150m MDPE
pipeline located in a container filled
with sand, outside of the lab.
Electrolysis setup
Alkaline Fuel Cell DCI 1200 Setup
The electricity produced was used to charge batteries or
was inverted to the grid.
Source: IRL
Electrolyser Stack Connection
positive
electrical
potential
water and
oxygen
outlet
negative
electrical
potential
hydrogen
pressure
meter
hydrogen
outlet
water inlet
Distilled water is pumped just through the anode
compartment (oxygen side) of the electrochemical cells
which is not pressurised.
Lynntech Electrolyser Stack
catalysed
membrane
metal
flow field
active area
of 33 cm2
Source:
Lynntech
Industries
The right stainless steel endplate (+ electronics) was used
for a previous application and was replaced by a titanium
endplate.
Electrolyser Stack - VI Curves
2.2
Average Cell Voltage (V)
2.0
1.8
8.2ºC
1.6
17.4ºC
22.5ºC
30.1ºC
1.4
36.4ºC
60ºC Lynntech
1.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Current Density (A*cm-2)
At higher stack temperature there is a higher electr.
current flow (higher hydrogen production) at the
same voltage due to improved reaction kinetics.
System Efficiency Estimation
•
Electrolyser: η = 65.3%  electricity (+heat)/hydrogen conversion efficiency
(at a current flow of 23,5 A)
- Not considered: hydrogen pressure energy output, power consumption of the
12W water pump, heat transfer with circulating water
•
Alk. FC DCI 1200: η = 41.1%  hydrogen/electricity conversion efficiency
(at 650 W electrical power output)
- Not considered: thermal energy output (approximately 20%  combined heat
and power efficiency over 60%)
The above efficiencies were calculated using the lower
heating value (LHV) of hydrogen.
Hydrogen production/consumption was estimated by
measuring the pressure increase/drop in the pipe.
Proven Wind Turbine • Rated power output: 2.2 kW
• Zebedee furl (+ cone) system
allows for dynamic balance
between the rpm and the pitch
of the airfoil.
 During stormy winds turbine
doesn’t stop, instead, keeps
generat. at nearly rated power.
Drawing: Proven Energy Limited
Air-X
400 W
Wind Power Control and
Electrolysis Container
3 x 48 W solar panels
for additional battery
charging
Distilled water tank
for the electrolysis
Hydrogen pipeline
- the top riser
Source: IRL
Electrolyser in the Container
Flash arrestor
Recombiner
Deionisation column
Electrolyser
stack
Dehydration unit
Circulating
water reservoir
Water pump
Source: IRL
Hylink Transition to Totara Valley
Pipeline mole ploughing
(60 cm deep)
Electrofusion joint between
the pipeline sections
MDPE Internal diameter: 16 mm
Outer diameter: 21 mm
Wall thickness: 2.5 mm
Length: 2 km
 Volume: 402 L
Welder for electrofusion
Source: IRL
Fuel Cell Connection
in the Woolshed
Pressure sensor
PEM fuel cell ReliOn
Independence 1000 (J48C)
IRL controller
IRL grid-connected
inverter
48 V gel battery bank
The batteries power the control and data logging equipment as well as
provide a necessary buffer for the fuel cell and inverter.
Operating PEMFC supplies the inverter and the controller as well as
charges the batteries.
Source: IRL
Hydrogen Diffusion Rate Estimation
The pipeline was pressurised with 4.1 barg hydrogen and
then the pressure drop was recorded.
Result:
Hydrogen loss: 42.5 kPa/week  7.5mol/week  15 g/week
 0.5 kWh/week at LHV  3 W
Currently, the fuel cell operates at pipeline pressure
between 1 barg and 2 barg, so at average 2.5 bar abs.
Using:
P  Amean  t  p
Q
 1.5 W mean power loss due
z
to H2 diffusion through pipe
walls during fuel cell operation
Hydrogen Permeability through PE Comparison
Massey University (at 20°C) :
Industry (at 23°C):
P  1.45 10 15
mol  m
m 2  s  Pa
Totara Valley (at 10°C):
P  5.5 10 16
mol  m
m 2  s  Pa
General rule of thumb for Arrhenius
equation: for every 10°C increase
the reaction rate doubles.
P  P0  e
 EP
RT
Or EP and P0 can be estimated by
measuring P at different T and solving:
EP 1
ln P     ln P0
R T
Frictional Pressure Drop Estimation at
Fuel Cell’s max. Output
• According to the manufacturer, the fuel cell consumes at 1 kW
15 stdL H2 /min  mean H2 velocity is 1.24 m/s
Re 
V di
 1057
• Due to
the gas flow is laminar, and hence, the

friction factor f independent of roughness f lam  64  0.061 .
Re
• Then the frictional pressure drop can be calculated using the
Darcy-Weisbach equation as follows:
2
L V
p  
 f lam  2.6kPa  0.026 bar
di
2
• Considering that the fuel cell requires low H2 pressure for
operation, the calculated pressure drop can be neglected.
HOMER Simulation of the current HyLink
System Configuration
Selected Results
Data Inputs
• Batteries’ task is not to store energy to meet community’s
load requirements. They cover the system internal
electricity needs, and PV panels can be thought as the
power source for that. For this reason batteries as well as
PV panels were excluded from the simulation.
• Wind resource data was taken from the NASA website,
however the four wind parameters (Weibull shape factor
etc.) derive from the previous study at Massey University.
• The average of one of the eight monitored sites at Totara
Valley was used as the primary load data.
• Furthermore, factual and not projected data was used e.g.
for the ReliOn fuel cell the lifetime of 4,000 operational
hours and not 40,000 operational hours.
HyLink System Schematics used in
HOMER
grid-connected
stand-alone
Providing Back-up Power
for Peak Loads (May)
3.5
AC Primary Load
PEMFC ReliOn Pow er
Grid Purchases
Capacity Shortage
3.0
Power (kW)
2.5
- Grid purchase
capacity constrained
at 2.3 kW
- max. hourly peak
load throughout a
year: 3.3 kW
- 1 kW fuel cell
2.0
1.5
1.0
0.5
0.0
9
10
11
12
May
13
14
15
Providing Back-up Power
for Peak Loads (July)
3.5
AC Primary Load
PEMFC ReliOn Pow er
Grid Purchases
Capacity Shortage
3.0
Power (kW)
2.5
- Grid purchase
capacity constrained
at 2.3 kW
- max. hourly peak
load throughout a
year: 3.3 kW
- 1 kW fuel cell
2.0
1.5
1.0
0.5
0.0
23
24
25
26
July
27
28
29
Providing Back-up Power
for Peak Loads
1.5
Air-X
PEMFC ReliOn Pow er
Capacity Shortage
Power (kW)
1.0
0.5
0.0
23
24
25
26
July
27
28
29
Due to small system configuration, esp. wind turbine/electrolyser,
very dependent on the prevailing wind conditions.
Daily Pipeline Filling Process
Fluctuations due to changing Wind
1.5
0.4
PEMFC ReliOn Pow er
Capacity Shortage
Stored Hydrogen
Power (kW)
1.0
0.2
0.5
0.1
0.0
23
24
25
26
July
27
28
29
0.0
Stored Hydrogen (kg)
0.3
Scenario for HyLink with added Massey University’s
2.2 kW Wind Turbine and IRL’s 1 kW Electrolyser
3.5
AC Primary Load
PEMFC ReliOn Pow er
Grid Purchases
Capacity Shortage
3.0
Power (kW)
2.5
The previous
capacity shortage
on 24th July is
compensated due
to improved system
response.
2.0
1.5
1.0
0.5
0.0
23
24
25
26
July
27
28
29
Scenario for HyLink with added Massey University’s
2.2 kW Wind Turbine and IRL’s 1 kW Electrolyser
2.5
Proven/Air-X
PEMFC ReliOn Pow er
Capacity Shortage
Power (kW)
2.0
1.5
1.0
0.5
0.0
23
24
25
26
July
27
28
29
Scenario for HyLink with added Massey University’s
2.2 kW Wind Turbine and IRL’s 1 kW Electrolyser
1.5
0.4
PEMFC ReliOn Pow er
Capacity Shortage
Stored Hydrogen
Power (kW)
1.0
0.2
0.5
0.1
0.0
23
24
25
26
July
27
28
29
0.0
Stored Hydrogen (kg)
0.3
Outcomes
• Low durability and high replacement cost of
electrochemical conversion devices represent the main
barrier in introducing the HyLink system
• Small-sized system very dependent on the prevailing wind
conditions – low energy buffer capability
• The 36%-efficient fuel cell/inverter subsystem consumes
the full pipe content (3.3kWh at 3bar pressure difference)
in ca. 1 hr at 1kW ac output.
• The wind turbine/electrolyser subsystem needs ~9hrs at its
rated power (80 stdL/hr, 360 W) to provide this hydrogen
content – at optimal wind conditions
• Hence, the fuel cell/inverter efficiency (36% electr.)
constrains the overall system performance and the small
wind turbine/electrolyser size slows the system’s response.
General Outcome
• Successful demonstration of a new energy
concept – in operation since May 2008
• The HyLink system reveals barriers and
opportunities of hydrogen based energy
systems.
• The HyLink system proves, that an energy
carrier can be produced from a renewable
resource high efficiently.
• The HyLink system proves that this energy
carrier can be transported via cheap pipelines.
• The HyLink system proves that this energy
carrier can be converted to electricity high
efficiently (not Carnot Cycle constrained), carbon
neutral and noiseless in fuel cells.
Acknowledgements
•
•
•
•
•
Prof. Ralph Sims (Massey University)
Attilio Pigneri (Massey University)
Steve Broome (IRL)
Edward Pilbrow and Eoin McPherson (IRL)
Jim Hargreaves (Massey University), Phil
Murray, Mark Carter
• Totara Valley residents
• and many others at Massey