Does the Barcelona-Marseille gas pipeline make sense to transport hydrogen?

In 1874 Jules Verne published The mysterious Island and assured:

“I believe that one day water will be a fuel, that the hydrogen and oxygen that constitute it, used alone or together, will provide an inexhaustible source of energy and light, with an intensity that coal cannot; since the coal reserves will be depleted, we will heat ourselves thanks to the water. Water will be the coal of the future.”

In the 70s of the last century, with the oil crisis, there was already talk of the hydrogen economy, and it was seen that it could be profitable compared to traditional fuels. However, that paradigm shift did not come to pass, and today we continue to be heavily dependent on fossil fuels. In the 1970s the market alone was not able to make the change. Now it is clear that a public impulse is necessary to make hydrogen a protagonist of the energy transition. The European Union has seen this point clearly.

A few weeks ago the agreement was announced between the governments of Spain, Portugal and France to build the so-called BarMar, the Barcelona-Marseille gas pipeline. It will first transport natural gas and, later, hydrogen, when this element has sufficient production and demand. It will take 4 to 5 years to build. Does this infrastructure make sense? It is not clear.

Hydrogen also consumes energy

In recent years, the possibilities of hydrogen have been revolutionizing the world of energy. It has in its favor that it is a gas that does not pollute, since its combustion emits only water. It has been identified as a key player in the fight against climate change because it perfectly meets the new commandment that we have imposed on ourselves in Europe: you will not emit CO₂ into the atmosphere.

However, it is not a source of energy, and it does not exist as such in nature, unlike current fuels such as oil, gas or coal. Producing hydrogen consumes energy, even more than that returned by its combustion. For this reason, it is said that hydrogen is an energy vector, the same as electricity: they are ways of transporting, storing and generating energy.

Hydrogen can be obtained in several ways, which are labeled with a color palette:

• gray hydrogen. It is the majority of what is currently produced. It is generated by reacting natural gas with water vapor. It has the drawback that CO₂ is emitted into the atmosphere, making it not valid for fulfilling that new commandment.

• blue hydrogen. It is obtained like gray, but capturing the CO₂ produced.

• Green hydrogen or low emission hydrogen. It is obtained by electrolysis of water, that is, breaking the water molecule with renewable electricity.

Green and blue are the only colors that meet the requirements for low emissions. There are also other colors in the palette, such as pink hydrogen, produced by electrolysis of water from nuclear energy; or dorado, produced from organic waste with CO₂ capture.

transportation methods

Once produced, the hydrogen must be transported to the place where it is consumed. As a principle, the ideal is to locate the production of this gas as close as possible to where it is used, but this is not always possible.

For not very long distances, hydrogen is transported in a similar way to butane cylinders: in cylindrical pressure vessels carried on trucks.

For greater distances, the most efficient is to have a network of pipes, the so-called hydroducts. In the short term, the current natural gas distribution network can be used by injecting some hydrogen into the gas network (so-called blending or mix). But to transport gas with high concentrations of hydrogen it is necessary to modify the pipes.

In addition, hydrogen, due to its low density, requires doubling the gas compression stations, that is, the distance between compression stations would be half that of natural gas.

Will Spain and Portugal have enough hydrogen to export it?

A pipeline like the BarMar, designed to transport hydrogen, could serve to transport natural gas and later replace it with hydrogen.

In a way, it can be said that a hydrogen pipeline is similar to an electrical cable: they are energy transport infrastructures. That is, a hydrogen pipeline is a way to export solar and wind energy. This is where the question about the convenience of the BarMar gas pipeline should be raised: this infrastructure only makes sense if Spain and Portugal are capable of producing enough renewable hydrogen to meet domestic demand and export the surplus through that pipeline.

There are two additional factors that must be taken into account: the increase in hydrogen production implies that it will be necessary to increase electricity production. The existing plants are not enough: more solar plants, more wind turbines and possibly more nuclear energy are needed.

In addition, to transport this electrical energy it will be necessary to install more high-voltage lines. We are well aware of the difficulties of these new facilities (solar parks, mills or power lines) in the form of social rejection –not in my yard–, but you have to face them with a lot of pedagogy.

Tomás Gómez-Acebo, Professor of Thermodynamics. Director of the Chair of Energy Transition of the Repsol Foundation, university of Navarra

This article was originally published on The Conversation. Read the original.