Hydrogen produced at “record-setting efficiencies”

Steam combined with high-temperature electrolysis has been found to have substantial potential when it comes to paving the way for large-scale hydrogen production in the nuclear industry. Bloom Energy and Idaho National Laboratory (INL) have been engaged in an ongoing demonstration, with close to 500 hours of full load operation completed at the laboratory and encouraging initial results.

Researchers have been conducting a series of tests on Bloom Energy's solid oxide electrolyser at the Dynamic Energy Testing and Integration Laboratory and discovered it is capable of producing hydrogen up to 45% more efficiently than PEM and alkaline electrolysers. Its solid oxide electrolysis cell is made up of an anode, cathode and electrolyte, with the electrolyte a solid ceramic material and the anode and cathode made from special inks. These inks then coat the electrolyte, facilitating an electrochemical pathway which is able to produce hydrogen from renewable electricity.

Tests have included steam and load simulations that replicate nuclear power station conditions. These revealed that the Bloom Electrolyser can produce hydrogen at 37.7kWh per kilogram of hydrogen, with 88.5% Lower Heating Value (LHV) to DC. For a means of comparison, other electrolyser technologies, such as PEM or alkaline, consume as much as 52-54kWh per kilogram of hydrogen produced. Dynamic testing also saw the system ramped from 100% of rated power to just 5% in less than 10 minutes, showing no adverse system impacts.

Nuclear plants, operating continuously and providing high-quality steam input, are well placed to use electrolysers efficiently and produce sizeable amounts of clean hydrogen, with little in the way of disruption to ongoing operations. However, despite global demand for hydrogen and its emerging applications being forecast to increase substantially by 2050, cost remains a primary barrier. It was noted that up to 80% of the cost of hydrogen through electrolysis is electricity. This is why Bloom Energy's Electrolyser, operating at high temperatures, could offer a path for hydrogen to become economically accessible, requiring less energy than low temperature PEM and alkaline electrolysers to split water molecules and producing hydrogen more efficiently too.