Energy, defined as the ability to produce transformations, whether elevating an object or by heating a part, it can be transported from one place to another using fuels (chemical energy carriers) or electricity (electrical energy carrier).

Considering the applications of interest in our daily lives, electricity and hydrogen are not resources or primary energy sources, taken from nature, but can be produced by various technologies, transported, stored and converted into other forms of energy, such as movement of a vehicle or lighting. In this way, electricity and hydrogen are similar.

One of the similarities has to do with its emergence and expectations of use. In the fascinating history of electrical energy, based on the brilliant contributions of scholars such as Benjamin Franklin, Alessandro Volta, Humphry Davy, Hans Christian Oersted and Michael Faraday, electricity progressively stopped being a feared curiosity and became something useful, currently essential.

In this sense, it is interesting to remember that, when demonstrating in 1831 the operation of an electric generator and asked about the usefulness of his invention, Faraday replied: “But what use is a newborn baby?” Although hydrogen was discovered by Henry Cavendish in 1766, reacting acids with metals and named in 1783 by Antoine Lavoisier, when observing that the combustion of this gas produced water, its effective application on a commercial scale only took place in the 20th century, initially in the production of ammonia, using the process developed by Fritz Haber and Carl Bosch in 1908 and later in petroleum refining, improving product specification and valuing lower-value heavy streams.

However, these hydrogen applications, which account for a large part of the more than 90 million tons of hydrogen consumed annually on our planet, use hydrogen produced from natural gas, oil and even mineral coal, with significant carbon emissions to the atmosphere.

The new hydrogen, which has mobilized enormous resources and redesigned energy strategies and plans, especially in developed and energy-dependent countries, is hydrogen produced from renewable energy, with a low carbon footprint and aligned with the current energy transition, capable of replacing fossil fuels.

This is the hydrogen that we must see as a child, the holder of so many hopes, capable of promoting a more sustainable future. Market projections for renewable hydrogen are challenging, indicating that by 2050 the annual consumption of this energy source could be in the order of 500 million tons, requiring investments of more than 30 trillion US dollars, according to the World Bank.

Supply has essentially been considered from electricity, and demand oriented towards mobility, of people and cargo, and industrial processes, especially ammonia (in this case green ammonia, with a low carbon footprint) and energy-intensive products, such as steel and cement. Such perspectives imply overcoming relevant technological challenges, due to the physical characteristics of hydrogen, which impose very high pressures and/or low operating temperatures, special materials, etc., which in turn entail high capital and operating costs. It is worth remembering that modern civilization overcame similar challenges in implementing current electrical systems and could, over time, also make the hydrogen economy efficient and competitive, leaving its current infancy and reaching maturity.

In the current incipient context of the global hydrogen industry, recognizing the relevant achievements of modern energy biotechnology in Brazil, it is opportune to explore new possibilities, without neglecting this gas as an energy vector, but opening other paths for its supply and demand, eventually more consistent and rational than the current protagonists have promoted for young hydrogen. Indeed, if the objective is to persevere in the energy transition, economically and effectively, modern bioenergy can and should be considered carefully, as we summarize below.

On the production side, it is important to note that electrolysis is just one of the ways to produce hydrogen, using electricity to separate the water components, at a rate of approximately 60 kilowatt hours per kilogram of hydrogen. There are other ways, especially using bioenergy vectors, such as for the reforming of biomethane, the main component of biogas, with a productivity of around 8 cubic meters of biogas per kilogram of hydrogen, the reforming of ethanol, with a productivity around around 9 liters of ethanol per kilogram of hydrogen.

Both of these endothermic processes are similar and technologically mature, in which with the aid of suitable catalysts and water, the energy from these biofuels allows maintaining reactors (reformers) with temperatures between 600 and 900 degrees centigrade, and producing streams with hydrogen, which can be purified up to high levels. It is not difficult to estimate the competitiveness of biogas and ethanol compared to electricity, especially if real values of capacity factors and investment and operating costs are used, which greatly reduce the attractiveness of electrolysis systems.

A third alternative is low-cost solid biomass gasification processes, such as agricultural and forestry residues, producing gases with lower hydrogen content, but which can also be purified. These last processes are under development, with promising results, however, without having yet demonstrated their economic viability.

Hydrogen consumption, from an economic and sustainable perspective, still needs to develop learning curves and establish itself on its own merits; As we know, this is a market in the early stages of development. However, it appears that industrial applications are the most promising, considering the potential demand for low carbon footprint products, such as fertilizers (green ammonia) and ferrous metals. In both cases, again, sustainable bioenergy has proven to be well-positioned to offer efficient and competitive routes.

In mobility applications, even considering the possibility of producing hydrogen with ethanol, if economic and environmental assumptions must prevail, the direct use of ethanol must be evaluated as the most efficient and competitive alternative.

Finally, it is imperative to be clear that photosynthesis, the fundamental reaction of life, is the precursor to the modern hydrogen economy. In the leaves, sunlight decomposes water, releasing oxygen and combining hydrogen with carbon dioxide absorbed from the atmosphere and forming sugars, the basis of all the diversity of biomass and its consequences, such as fuels. The hydrogen in ethanol, biogas, and all biomass came from water, produced with solar energy. Thus, the hydrogen present in bioenergy is not a child, it is as old as life on our beautiful planet.

Note: As a complement to this article, see Horta Nogueira, L.H., Renewable hydrogen from biomass: perspectives in Brazil, Revista Opinões, Year 19, number 74.