DTU Energy Conversion and Haldor Topsøe A/S have received funding from the Danish Energy Technology Development and Demonstration Programme to research into energy efficient production of pressurized hydrogen.
Hydrogen can be produced by using electricity to split water through electrolysis. It has a wide variety of uses, from weather balloons to environmentally friendly fuel for fuel cell cars.
The potential of hydrogen is huge, but large scale industrial hydrogen production has so far been limited by two dominant factors: the system investment costs and the electricity cost.
The project “Energy Efficient Production of Pressurized Hydrogen”, E2P2H2, aims to demonstrate energy efficient production of pressurized hydrogen using pressurized solid oxide electrolyser cells. The project also examines the techno-economic potential of the production method for large-scale production of hydrogen.
A pilot project led by senior researcher Søren Højgaard Jensen at DTU Energy Conversion has demonstrated that systems based on high temperature electrolysers such as solid oxide electrolyser cells (SOECs) can be made very energy efficient because the electricity demand of the water electrolysis reaction improves with increasing temperature.
Also the SOECs are made from relatively cheap raw materials, i.e. without noble metals such that the technology holds a potential for low investment costs around 150 €/kW.
Results from the pilot project at DTU Energy Conversion and other pilot projects at Haldor Topsøe A/S shows that cost efficient hydrogen distribution and storage requires high gas pressure. Thus hydrogen production based on low-pressure electrolysers necessitates costly electricity consuming compressors. The internal resistance in the SOEC cells also decreases with increasing operating pressure. This means that pressurization of the SOEC can both improve the efficiency of the electrolysis process and decrease the electricity consumption required to pressurize the hydrogen. Hydrogen production using pressurized SOECs are expected to be around 40 % more energy efficient than traditional electrolysis technologies and about 10% more energy efficient than hydrogen production using low-pressure SOECs.
In short pressurized SOEC technology enables an energy efficient production of pressurized hydrogen. And the main results of the joint DTU/Haldor Topsoe A/S project are expected to be a demonstration of hydrogen production with a 1 kW SOEC stack using highly active electrodes at temperatures around 600 - 750 ˚C and pressures up to 30 bar using pressure tanks known as autoclaves, and a techno-economic evaluation of the concept.
The project is expected to give important feedback to the technology development and provide much needed experimental validation of the improved system efficiency under these novel operating conditions.
“I am really looking forward to demonstrating SOEC-tests at 30 bar as it will be very relevant for effective and affordable hydrogen production”, says project leader Søren Højgaard Jensen from DTU Energy Conversion.