The power of

by Charles Lhuillier

Have you ever thought about what holds your body together? Why are our constituting atoms – those elementary blocks of matter – not split apart in the interstellar void by gravitation, as every stardust should be? This internal cohesion of matter is enabled by inter molecular forces. This means that, at a certain level, every basic particle of matter is subject to attracting forces that can counter gravitation, and so bring the particles together.

At subatomic level, the strong interaction draws protons and neutrons together, while electromagnetic forces capture the electrons in a surrounding electronic cloud. Quantum physics gives each atom a respective level of energy, associated with a given stability. Since physical systems tend to evolve towards higher stability, isolated atoms are likely to associate through electrochemical or weak interactions, creating more stable matter structures such as ionic compounds, complexes or molecules. You can picture these interactions just like the ones affecting the two poles of a magnet.

When the positive pole is facing the negative pole, they attract each other and can eventually bind together. This is similar to what happens to atoms when they form molecules. The forces that hold the bonds between atoms correspond to a certain amount of energy.

We now realize how the power of molecules makes the fundamental bricks of our body stick together. Bigger associations of atoms, molecules and ions create bigger molecules, such as proteins, that again bind to create cells, and so on until your entire body is created!

Throughout human life, energy is consumed by the body to provide many physiological functions, including muscle displacement that allows us to breathe, our heart to beat etc. That energy is absorbed from molecules of the food we eat, as well as other nutrients that form the building blocks of our body. While those building blocks assemble to form cells, tissues and organs, as discussed earlier, other ingested compounds will feed the power plants of our body. Energetic molecules, such as sugars, are chemically broken down into smaller parts of the cells, and the energy of their bounded molecules is released for the use of the cell. As oxygen is required for this transformation, it is accessed through the air that we breathe. Thus, our bodies use hydrogenated organic molecules to harvest the energy it needs to breathe, move and think.

On a social scale, energy is everywhere. We need it primarily to stay warm, to have light and to produce our food. However, many other needs require huge amounts of energy, such as mobility, communication, and generally manufacturing of all kinds of objects, which have been mainly retrieved through fossil fuel combustion, which consists of chemicals reactions, breaking down energized molecules, formed during prehistoric times, by the decomposition of biological matter in the presence of oxygen. A very similar chemical phenomenon happens in the body during digestion, though at a much slower pace. The main products of combustion, apart from energy and light, are carbon dioxide (CO2) and water. It becomes clear today that the anthropic release of CO2 , into the atmosphere, causes major changes in the global climate by increasing the greenhouse effect. High-level mitigation strategies to this evolution will involve reducing the energy consumption by increasing the efficiency and diminishing the losses of all energy-consuming processes (household heating, industrial processes, vehicles operation…) and transitioning towards a great share of zero-carbon energy sources. Sun and wind are identified as the main renewable sources and the energy they carry is already harvested worldwide. But during periods of insufficient sun or wind exposure, a significant risk of energy shortage exists, if no alternative to the primary renewable sources is provided. Conversely, periods of sun and wind harvesting exceeding the energy demand can be seen as losses.

Consequently, the contemporary and essential energy transition requires a solution to manage the variability of the renewable energy sources. This solution could be managed through inter molecular forces. It is indeed possible to use the excess electricity, produced after some steps from sun and wind to synthetize energetic molecules, that can be stored in gaseous or liquid form until the energy demand reaches a new high. The electrical energy is converted here into chemical bonds that can be broken down later to restitute a fraction of the original energy. Hydrogen is the most well-known element used for this purpose. Indeed, it can be directly produced from water and electricity using a technique called electrolysis. However, hydrogen is a very light, volatile and flammable molecule, and so quite difficult to store and transport at reasonable costs. A hydrogen leakage is quite critical since the first hotspot nearby could cause a fire or an explosion. Nevertheless, it is a very useful feedstock in many applications and it is starting to gain major interest in renewable dominating energy systems. Further energetic molecules can be synthetized from hydrogen, facilitating the storage and transport. Ammonia, Methane and Methanol are such candidates and a lot of scientific research is on the go to optimize their production from renewable sources and the restitution of the energy that their molecular bonds contain after the period of storage.

The future of our civilization will become more dependent on how well we manage the energy transition from a fossil-fuel-dominated market, associated with non-sustainable CO2 emissions, towards an efficient and sustainable renewables energy society. A key factor of success will be determined by the kind of inter molecular forces used to give the energy system enough flexibility, using smart and clean fuels. But, just as in our body, storing excessive amount of energy will not be the solution: energetic sobriety should remain our guiding principle.