Present and future of hydrogen. Part 1

Alberto Fernández

17 Dec, 2021


A new energy resource...

Wich, in reality, has always been there

Imagine that the interested reader is suddenly confronted with these words: “One day, water will be a fuel. The hydrogen and oxygen that constitute it, used alone or together, will provide an inexhaustible source of energy and light. Since coal reserves will be exhausted, we will be heated by water. Water will be the coal of the future.”

It will hardly be missed. So much is written and spoken about hydrogen these days that these words will strike you as just one of many that are published almost daily in the media. The interesting thing is that they were not published yesterday, last week or a month ago. They are more than 150 years old, as they are included in Jules Verne’s The Mysterious Island, a novel published in 1874.

It is not the first time, nor will it be the last, that we will see that many passages by the French writer have an eerie prophetic power. In any case, they serve to relativize and put into perspective a very current phenomenon: many people think, quite logically, that hydrogen is a new energy resource that has unexpectedly burst onto the industrial and economic scene. This is not the case.

Decades of exploitation

In fact, almost since its discovery, hydrogen’s ability to store energy has been well known, and it has played an important role in the energy industry and in locomotion ever since. In the 1960s, it was used as a propellant for spacecraft and for fuel cell power generation in space. And in the same decade, the first hydrogen-powered passenger cars appeared. Thirty years later, hydrogen and fuel cells underwent a major technological development, always with a focus on the mobility sector. 

Hydrogen has therefore been a very important product for our economy for a long time, and work has been going on for many years to find the best way to produce it as efficiently, cleanly and economically as possible.

However, it is true that it is only more recently, in the first decade of the century, that a much greater focus has been placed on hydrogen, as a consequence of the fundamental role it can play in the process of ecological transition and in an increasingly energy-intensive world.

For this reason, we are now in an ideal position to give a major boost to its use, as the global commitment to reduce CO2 emissions in a joint effort to prevent the planet’s global temperature from rising requires, among other alternatives, that we give the technological developments on hydrogen that have been worked on for so many years the boost they need to make it a competitive resource compared to traditional technologies.

A reality for very important and varied uses

In this respect, it is important to bear in mind that we are not talking about hypotheses, but about applications that have already been tried and tested. Hydrogen is already the basis to produce a multitude of products that are essential in our daily lives and is becoming increasingly important in the development of sustainable mobility with free or lower CO2 emissions, together with liquefied gas (LPG) and electric vehicles. 

In turn, the same need to reduce greenhouse gas (GHG) emissions makes hydrogen a star compound for storing energy from renewable sources in fuel cells, as battery storage is currently only feasible in small-scale installations. These fuel cells have a great future ahead of them through their application in vehicles and for regulating electricity market demand. In addition, hydrogen can be produced by electrolysis when electricity is cheaper from renewable sources, stored and then converted back into electricity when electricity is more expensive to produce. 

Hydrogen can also be converted into other energy-bearing compounds, such as methanol, methane, ammonia, etc., which enables different forms of energy use, transport and storage. On the other hand, its conversion into other chemical products also contributes to the reduction of greenhouse gases in the refining industry, petrochemicals and fertilizer production, thus contributing to decarbonization goals.

Another widespread use today, and perhaps little known, is the injection of hydrogen into natural gas networks, mixing it with the natural gas that finally reaches our homes. This is already done in a proportion that currently varies from 5% in countries such as Spain to 20% in other European countries, depending on the technological characteristics of the boilers, an aspect on which progress is being made. It is true that, when hydrogen is mixed with natural gas, the resulting calorific value is lower than that of natural gas alone, so it is necessary to consume a little more fuel to heat our homes to the same temperature, but in exchange much less CO2 is emitted into the atmosphere, so the resulting effect is much more favorable from the point of view of decarbonization.

Challenges and clichés

The solutions that hydrogen can provide to present and future energy consumption problems are therefore varied and important, and are rapidly achieving an increasing level of maturity.

Certainly, there are challenges to overcome before this can be fully realized. One example is electrical efficiency. Current electrolyzers – that is, equipment that produces hydrogen through electrolysis, a chemical process that separates the hydrogen and oxygen molecules that form water – have an electrical efficiency of 63%-70% for alkaline electrolyzers and 56%-60% for polymer proton membrane (PEM) electrolyzers. However, work is underway on solid oxide electrolyzer cells that could achieve electrical efficiencies of up to 90%.

On the other hand, although misconceptions sometimes circulate, it is a resource that does not pose particularly relevant safety problems. It is, of course, a highly flammable and combustible gas, but only in the presence of air and an ignition source. In other words, it is not explosive, just as it is not toxic, corrosive or polluting. In addition, various international norms and standards (ISO) guarantee its safe use. On the other hand, it is stored as a pure compound, in totally airtight containers that are designed with wide safety margins; and it can be transported safely over long distances in pressurized or liquid form.

Another issue that is often discussed with respect to the current use of hydrogen, and on which there are also some important interpretative biases, is that of the comparative cost with other energy solutions.

But this is another issue that can be the subject of detailed reflection in a forthcoming article…

back to top