Context:
Recently, Germany launched the world’s first fleet of fully hydrogen-powered trains, these are emissions-free trains that can reach speeds of 140 kilometres per hour and can run about 1,000 km before the tank runs dry.
Relevance:
GS III: Scientific Innovations & Discoveries
Dimensions of the Article:
- About Hydrogen fuel cells
- How are they different from conventional Batteries?
- Advantages of the Hydrogen Fuel Cell technology:
About Hydrogen fuel cells
- Hydrogen fuel cells are a clean, reliable, quiet, and efficient source of high-quality electric power.
- They use hydrogen as a fuel to drive an electrochemical process that produces electricity, with water and heat as the only by-products.
- Hydrogen is one of the most abundant elements on earth for a cleaner alternative fuel option.
How does it work?
- A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen in the case of Hydrogen Fuel Cell) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions.
- A Fuel Cell consists of an anode, a cathode, and an electrolyte that allows ions, often positively charged hydrogen ions (protons), to move between the two sides of the fuel cell.
- A fuel cell converts chemical potential energy (energy stored in molecular bonds) into electrical energy.
- A PEM (Proton Exchange Membrane) cell uses hydrogen gas (H2) and oxygen gas (O2) as fuel.
- The products of the reaction in the cell are water, electricity, and heat.
- This is a big improvement over internal combustion engines, coal burning power plants, and nuclear power plants, all of which produce harmful by-products.
- Since O2 is readily available in the atmosphere, we only need to supply the fuel cell with H2 which can come from an electrolysis process (see Alkaline electrolysis or PEM electrolysis).
How are they different from conventional Batteries?
Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from metals and their ions or oxides that are commonly already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.
Advantages of the Hydrogen Fuel Cell technology:
- By converting chemical potential energy directly into electrical energy, fuel cells avoid the “thermal bottleneck” (a consequence of the 2nd law of thermodynamics) and are thus inherently more efficient than combustion engines, which must first convert chemical potential energy into heat, and then mechanical work.
- Direct emissions from a fuel cell vehicle are just water and a little heat. This is a huge improvement over the internal combustion engine’s litany of greenhouse gases.
- Fuel cells have no moving parts. They are thus much more reliable than traditional engines.
- Hydrogen can be produced in an environmentally friendly manner, while oil extraction and refining is very damaging.
-Source: Down to Earth
