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Posted: Nov 29, 2013
Improved hydrogen-powered heat and electricity for homes
(Nanowerk News) Some homeowners have already invested in units that produce hydrogen through water electrolysis so as to produce electricity and heat without boilers. Enhanced electrolysis should increase efficiency and decrease costs for greater uptake.
Stand-alone units that generate combined heat and power (CHP) for homes, micro-CHPs, are a very efficient, sustainable alternative to the use of a gas boiler. The micro-CHP units are fuel-flexible, meaning that they can use a variety of different fuels. One promising version relies on hydrogen gas. This is produced via electrolysis of water, stored for on-demand use, and its chemical energy is converted by the CHP unit into electrical energy and heat with water as the only output.
Minimising the cost and increasing the durability (which in itself reduces lifetime costs) of the electrolysis unit would significantly increase market uptake. Scientists developed and tested an improved proton exchange membrane (PEM) water electrolyser to fuel micro-CHP through EU funding of the project 'Pressurized PEM electrolyzer' (PRIMOLYZER).
PEM electrolysers use a polymeric membrane electrolyte and platinum (Pt)-based electrodes to decompose water into hydrogen and oxygen. PRIMOLYZER studied and developed novel catalysts and polymeric (perfluoro sulfonic acid (PFSA)-based) membranes with similar thermal stability and mechanical properties but improved electrical properties compared to state-of-the-art membranes.
Partners put all the components together in membrane electrode assemblies (MEAs), several of which were tested over long periods of time to evaluate durability. Two PEM electrolyser stacks were produced from the best performers. The membrane and oxygen evolution reaction catalyst were better than commercially available competitors and the purity of the hydrogen produced was quite high, fuelling the operation of a low-temperature PEM micro-CHP with no problems for approximately 220 hours. Cost analysis points to a nearly 50 % reduction in single electrolyser cost when production goes from 1 to 100 stack units.
PRIMOLYZER delivered a polymeric membrane, catalysts, MEAs, stack components and a stack capable of commercialisation within a few years. Not only that but the project developed hydrogen production technology applicable to a variety of energy domains in a future hydrogen economy. Concepts will be further developed within the scope of a project continuation, PRIMOLYZER phase II. In the meantime, outcomes make a significant contribution to the EU's goals for sustainable hydrogen production and supply chains.