TELF AG examines an energy innovation in the hydrogen sector 

Electricity and heat 

The potential of hydrogen is being explored by many sectors, even very different from each other, including aviation, energy storage (especially for renewable energy), but also those related to the metal industry and space exploration. One of the most interesting experiments, however, has to do with the ability of hydrogen to actually generate electricity and heat for domestic use, with the possibility of even powering entire residential complexes capable of housing several hundred families. 

This is precisely what happened recently in the city of Ulsan, in South Korea, where the first condominium in the world powered entirely by hydrogen fuel cells was officially inaugurated, which generated 100% of the heat and electricity for domestic use. Fuel cells are special electrochemical devices that, through a specific reaction with oxygen, can directly convert the chemical energy of hydrogen into electricity and heat. 

The apartment complex was powered by a thermoelectric plant just 200 meters from the houses. The plant used hydrogen as a by-product and channeled it to the apartments thanks to a 10 km pipeline shared with some local industries. Three small fuel cells were positioned on the complex roof, and in just one hour, they generated about 1.31 megawatts of electricity from 51 kg of hydrogen. 

How fuel cells work 

With this method it was also possible to generate heat, which was then stored in a thermal accumulator with a capacity of 40 tons. This made it possible to heat the water for use in the houses, which reached temperatures of up to 70 degrees. In June, the apartments in this complex – called Yuldong-With-U – were able to generate 840 MWh of energy, which in a traditional bill would reach an economic value of over 100,000 dollars. With this method, as reported by some media, energy costs could be lower. 

But what are the advantages of hydrogen valorization through fuel cells? The first is about the overall efficiency, which would be much higher than combustion engines. In fact, through cells, it is possible to convert the chemical energy of the fuel directly into electrical energy. According to estimates by the United States Department of Energy, this method would be characterized by an efficiency percentage of over 60%. The operation of fuel cells, in some ways, is very similar to that of batteries, but unlike the latter, they do not need to be recharged and do not run out. Indeed, these devices do not stop producing electricity and heat until the fuel supply ceases. 

Individual cells consist of two electrodes, one negative and one positive, generally known as the anode and cathode, with an electrolyte. In hydrogen fuel cells, hydrogen molecules are separated by a catalyst at the anode, which splits them into protons and electrons. The protons then move to the cathode, where they combine with oxygen and electrons to form water and heat.