Hydrogen to store renewable energy: the European HyCARE project

“I call him Hydrogen Dayon 8 July 2020, when the vice-president of the European Commission Frans Timmermanscoordinator of the European Green Deal, has turned the spotlight on hydrogen as a key solution for decarbonisation”, ironically acknowledges Professor Marcellus Baricco, full professor of Materials Science and Technology at the Chemistry Department of the University of Turin. “But in reality we have known a lot about this gas for some time and although there have been strong technological evolutions in recent years, we cannot speak of revolutions: the moment has just come to take advantage of the opportunity, now or never”.

And one of the occasions is called HyCARE, that is Hydrogen CArrier for Renewable Energy Storagea project that aims to create a system capable of store the energy produced from renewables through hydrogen, with a higher level of efficiency than current standards. After that, it is known that hydrogen can be used as an energy vector to power road vehicles, trains, ships and, in the future, also for the decarbonisation of industrial processes in large factories.

HyCARE, a great European project

HyCARE was born as a community project and its consortium sees the participation of research centers of theUniversity of Turin with Environment Park of Turinof the Center for Sustainable Energy of the Bruno Kessler FoundationofHelmholtz-Zentrum Hereon (Germany), fromInstitute for Energy Technology (Norway) and del CNRS – Center national de la recherche scientifique (France). Added to these is the fundamental contribution of companies Tecnodelta Plants of Chivasso (To), GKN Sinter Metals Engineering (Germany) e Stühff Maschinen- und Anlagenbau (Germany). After almost four years of work, just last April 21st, the final chapter of this adventure was reached. “We have presented the first working demonstrator at the Engie Lab Crigen, near Paris, because our French partners have a 55 kW proton exchange membrane (PEM) electrolyser as the hydrogen producer and a 55 kW PEM fuel cell 20 kW as a user”, explains Baricco, the coordinator of the entire project.

The HyCARE system actually acts as an intermediate stage between the system that produces hydrogen and the battery that allows it to be used. The project focuses on hydrogen management using a carriera courier in short. The basic idea is to optimize the process behind the management of hydrogen, obviously in safety, reducing environmental impacts and improving overall efficiency.

Energy storage using hydrogen

“Net of use as fuel – in Japan hydrogen cars have been traveling since 2010, while in Germany a train has already been in operation for some years – energy storage is one of the most interesting development fronts for hydrogen at the moment. Indeed, once renewable energy has been used to produce it, this gas can be stored and, when desired, reused to generate new energy. Even after a long time, even a year or more if necessary”, underlines Baricco.

Historically, hydrogen has always been considered a bizarre object, cloaked in presumed danger. Almost a ghost of collective memory which in some recalls the tragedy of the Hindenburg airship (1937) and in others the H-bomb experiments in the first post-war period (1952). “Actually, the industry has always managed it: think of its use to produce theammonia with which fertilizers are made. It is an offense to common sense and to reality to consider it generically dangerous. Of course it must be treated properly, but the same also applies to the methane“, points out the chemistry professor.

One wonders why this solution hasn’t already been thought of in every area where there is a need for energy storage. “The answer is that you need to choose the most suitable technology, based on your needs, considering as parameters the amount of energy to be stored per cubic meter or per kilo, the power required and the storage time. Obviously not counting the investments and operating costs “, recalls Baricco. “For example, a package lithium ion batteries it is certainly cheap, it can be good for managing the hourly fluctuations of a domestic user, but if the power involved rises a lot or you need long-term storage, you have to think of something else”.

A wind power plant or a photovoltaic park are capable of generating large quantities of renewable energy, but there are moments of the day when the demand is amply satisfied and what has been produced must not be wasted. So why not make the most of this resource? The idea is that, regardless of the time component of production, energy can be allocated to a place until it is needed again. However, it is good to be clear that it is energy storage with hydrogen it is a strategy to avoid waste, because the efficiency rate of the process is still around 50%. “Making 100 the amount of energy produced from renewable sources, if this is used to produce hydrogen to be set aside and then subsequently reconverted into electricity, you get 50. A great result, if compared with the zero generated by total waste”, he assures Baricco.

How HyCARE works

The HyCARE project involves the use of hydrogen as energy carrier, or carrier of energy. It is a way of transforming the energy produced by a renewable plant into a gas to be crammed into a sort of container. After which, after some time, the gas is withdrawn and transformed back into energy. Up to this point it is an already theorized and practiced operation, although not yet so widespread, while the added value of the European project is to add a further element of efficiency.

Normally, as also in this case, we start with the use of energy (from renewables) to stimulate a chemical reaction that separates the water. The so-called electrolysis releases oxygen and hydrogen; the latter can be stored in different ways or used directly. For example, in cars the hydrogen is compressed to 700 bar in the tanks and with a full tank of about 3 kg you can travel over 600 km, while in trains the pressure drops to 350 bar, but the tanks are larger. In the case of HyCARE – and therefore speaking of renewable energy storage – there would be a need for large volumes and a high energy consumption for compression. in this way theefficiency goal, moreover requested by the EU Commission itself, should be reduced. Having discarded the hypothesis of transformation into liquid hydrogen – the temperature should be reduced to -253° C – all that remains is to focus on the use of hydrides.

In practice, it is necessary to ensure that the gas molecules interact with a metal powder, so as to obtain a hydride, a sort of hydrogen carrier. So far there is already something similar on the market, but no one had thought of picking up the heat that develops in this absorption process, convey it into a phase change material, which from solid becomes liquid and stores it. Then, conversely, the heat is transferred to the hydride, which releases the hydrogen again as a gas. All without the use of (other) heat or electricity from the outside. Synthesizing: to provide energy from the hydride, the same heat that was collected in the first phase to obtain it is used. So here is a complete cycle, carried out efficiently, minimizing any energy dispersion.

“Our demonstrator with about 45 kg of hydrogen stored in hydride would make it possible to power, for example, an apartment for several weeks. With this project we wanted to demonstrate that what is predicted in theory can be achieved in practice. Now all that remains is to understand if the The EU Commission is still willing to invest in this project to optimize the design of the plant and to reduce its size, or the time has come to rely on the companies involved for an application to offer to the market”, concludes Baricco. “However, there is still a hydrogen supply chain issue to be addressed: centralizing storage production or decentralizing it, considering hydrogen valleys small and large? Difficult to answer, but now is the right time to do it.”