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