Renewable Energy Sources - Hydrogen-Powered Fuel Cells

The world is developing. Fuel, water, electricity needs are rising in the same way with the development. According to the data of 2015, the energy use of the world is 168,5 terawatt hours. In order to imagine this amount of energy we can give an example. 168,5 terawatt hours equals the energy required to operate a small kettle for 15 billion years (15 billion years is about the age of the universe). Most of this energy is produced from coal and oil, which is called "Fossil Fuels". The name of Fossil Fuels is taken from the fossil remains of living organisms. Fossil fuels are formed by dissolution of organic residues (fossils) in an oxygen-free environment for millions of years.

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22% of the world's primary energy production and about 39% of the electricity production are based on coal. In this energy source, coal is burned to produce steam, and steam is produced by rotating the turbines.

The year 2016 was the hottest year go down in history. And the main reason for this warming is carbon dioxide, which we release to the world for reasons such as fossil fuels, cars and so on. However, there are also other sources of energy that do not release atmospheric carbon dioxide while generating energy. We may talk about

• Solar energy
• Wind power
• Hydroelectric for these energy sources.

Actually, energy cycles are not simple on solar panels. The reason for this is the efficiency of solar panels. Yield loss is usually caused by the fact that solar photons do not fall vertically into the pan and the inefficiency of the semiconductors. Large turbines, which first convert the kinetic energy of the wind into mechanical energy and then electrical energy, enable us to use wind energy. But after such a cycle the yield drops naturally.

Energy is conserved according to the first law of thermodynamics, but it is necessary to lose efficiency between the energy cycles according to the second law.

Another source of renewable energy used in the production of electricity is the fuel cells that use the simplest element as a source. Fuel cells are a source of energy that consists of semi-permeable membranes. Simply it combines 2 hydrogens with 1 oxygen and allows electrons to pass through the anode and produce electricity. Here the only waste is water.

Hydrogen and oxygen enter the system from different places in this system. The reactions are as follows,

2H² → 4H⁺+ 4e^-

The released electron transits through a trough to form a current in this reaction. The next reaction takes place between hydrogen and oxygen and forms water as waste.

4H ⁺ + O₂ + 4e^- → 2H₂O

The task of the semi-permeable membrane is to pass only protons and not allow electrons in this system. therefore hydrogen is an excellent candidate for this reaction because it consists of only one proton and one electron.

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Hydrogen is produced as a byproduct in the chemical industry, and 108 kg of hydrogen can be obtained from 1 m3 of water with the help of solar energy.

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The biggest problem is the storage of hydrogen. Hydrogen becomes liquid at a temperature such as -2530 °C at atmospheric pressure. This means that either very large pressures or very small temperatures are required to store the hydrogel in liquid form. Liquid storage costs too much but can be done. The cheapest method of hydrogen storage is to store large quantities of underground, exhausted oil or natural gas reservoirs in a similar manner to the natural gas. However, hydrogen can easily be converted into hydride form in large quantities with some metals and alloys.

In my opinion, if a good storage method is found, one of the most useful of renewable energy sources will be hydrogen fuel cells. Energy meets various challenges when shaping our life and bringing electricity to our homes. While energy is heading towards a dead-end street called fossil fuels, we must think ahead and accelerate the transition to renewable energy sources.

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Image Sources

• Thumbnail - Renewable Energy
• Fuel Cell Animation
• Hydrogen Storage Tank

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References

• http://www.renewableenergyworld.com/hydrogen/tech.html
• https://en.wikipedia.org/wiki/World_energy_consumption
• http://www.hydrogenics.com/technology-resources/hydrogen-technology