Electricity can be generated at hydroelectric power stations, nuclear power stations, with wind generators or solar cells, and so on. In the case of wind and solar energy, the need to store energy arises, as wind and sunshine are not always available. Unfortunately, electric energy cannot be simply put in a jar and stored in a cellar.
One possible option is to store energy in an energetic compound, e.g., hydrogen. It can be compressed in tanks and transported. If needed, hydrogen can be converted into electricity again.
This video demonstrates a technological solution where:
1) Wind energy is converted into electricity:
wind energy → electricity
2) Electricity is used to carry out the electrolysis of water, yielding hydrogen and oxygen (electrode reactions in related video: ”Electrolysis of water“):
2H2O(l) + electricity → 2H2(g) + O2(g)
3) Hydrogen and oxygen are stored in special vessels and can be converted into electricity again:
2H2(g) + O2 (g) → 2H2O(l) + electricity
This solution was demonstrated using:
1) A wind generator model
2) An electrolyzer|fuel cell system, specifically a reversible polymer electrolyte fuel cell PEMFC
This PEM fuel cell has two parallel electrodes immersed in water. Electrode material is carbon fiber which is coated with porous carbon, Nafion®, and a catalyst (likely platinum). From the outside, you can only see a metal mesh which behaves as a current collector. Electrodes are separated by a proton-conductive Nafion® membrane (polyperfluorosulphonic acid—C17HF13O5SC2F4). It allows the passage of hydrogen ions, but stops the gas molecules.
The device functions both as an electrolyzer and a fuel cell:
1) The electrolysis of water is started by applying the electricity generated by a wind turbine. The generated hydrogen and oxygen flow into respective tanks.
2) If there is no wind, hydrogen and oxygen can be supplied back to the fuel cell by applying slight pressure. When the load is connected to the fuel cell, it consumes the hydrogen and oxygen, producing water and electricity.
The electricity generated in the fuel cell was used to power an electric motor that lifted weights or propelled a car model.
The HydroWind Kit was provided by the "HORIZON" company. Electron microscopy images were taken by Jekaterina Kozlova (University of Tartu).
Hydrogen, either compressed or stored in hydride form, can be used as a fuel in cars. Unlike regular gasoline vehicles which produce CO2, hydrogen-powered vehicles emit only harmless water vapor.