Electrolysers for Hydrogen Production
Electrolysers for Hydrogen Production
by Peter Sudol
Methods of Hydrogen Production
Hydrogen
Electrolysis of WaterReforming of Biogenic andFossil Fuels
Uses of the Water Electrolysis
• Submarines, space stations (generation of breathing oxygen)
• Medical, chemical and other special applications• In great quantities, economic only in those regions of the
world where electric power can be generated very cheaply. This is the case almost exclusively in big hydroelectric plants (e.g. in Egypt, Iceland, Norway..).
• In the increasing renewable energy market, Water Electrolysis can be used for compensation of the differences between the demand and supply of energy from the variable renewable energy resources.
Hydrogen pipeline project in Totara Valley
Wind Energy
ElectrolyserPipeline 2km Fuel Cell
Hydrogen Burner
Types of Water Electrolysis
Water Electrolysis
Alkaline Electrolysis PEM Electrolysis Steam Electrolysis
Characteristic PEM Electrolysis Alkal. Electrolysis
Max. pressure of electrochemically generated H2
can be designed to generate H2 at press. of 2000 psi or greater
lower pressure of electrochemically generated H2
Efficiency lower parasitic energy losses
best alkaline electrolys. have still better efficien.
(high heating value)
Hydrogen/Oxygen
Pressure
up to 3,000 psi
differential pressure
demonstrated
very small differential
pressure tolerated
Purity of the hydrogen output
higher lower
Characteristic PEM Electrolysis Alkal. Electrolysis
Compatibility with renewable energy systems
best suited for plants with varying output
work better in larger systems which are connected to the power grid
Hazardous materials none, system uses clean water only, no hazardous waste
system uses KOH, waste disposal rules may apply
Occupational safety no special safety
equipment required
may require eyewash station or full-body shower
Explosion risk H2 released safely via normally open valves at shutdown or power failure
requires special controls to allow for a safe reaction between O2 and H2
PEM Electrolyser (two cells)
Principle of a PEM electrolysis cell
Nafion - Membrane
sulfonated polytetrafluorethylene
hydrophilic(polar)
hydrophobic(nonpolar)
UI characteristic curves of an electrolyser
Current density [mA/cm2]
Cel
l Vol
tage
[V
]
UI characteristic curves of an electrolyserC
ell V
olta
ge
[V]
Current density [mA/cm2]
UI characteristic curves of two electrolysersC
ell V
olta
ge
[V]
Current density [mA/cm2]
Further Steps in the Research Project
• Simulating the distributed energy system in the laboratory
• Determination of the efficiency of the whole system• Optimisation of the efficiency• Observing the performance of the electrolyser at
different temperatures, different pressures, different inputs
• Observing the distribution and pressure of Hydrogen in the pipeline
• Observing the performance of the fuel cell