Subject:- Renewable Energy Sources

Topic:- Energy Management

Difficulty:- High

Working of fuel cell.

• Basically fuel cell is a device which converts chemical energy from a fuel into electrical energy.

• It happens by undergoing a chemical reaction where positively charged hydrogen ions reacts
with oxygen or any other oxidizing agent.

• The fuel cell consists of two electrodes where the reaction takes place, one is positively charged called anode and the negatively charged called cathode.

• Every fuel cell comprises of an electrolyte and a catalyst to fasten the reaction rate and to mobilise the ions to one electrode to the other.

• A single fuel cell generates a tiny amount of direct current (DC) electricity.

• At anode catalyst oxidizes the fuel usually hydrogen turning the fuel into positively charged ion and negatively charged electron.

• Electrolyte substance specifically designed so ion can pass through it-electrons cannot

• Free electrons travel through wire creating electric current ions travel through the electrolyte to the cathode.

• One reaching cathode ions reunited with electrons react with third chemical usually oxygen creat water or carbon dioxide .

• The fuel cell produces power through redox reaction between hydrogen is oxidized

According to the reaction

$2H_2+4OH^- ----\gt 4H_2O + 4e^-$

• Producing water and releasing two electrons.

• The electrons flow through an external circuit and return to the cathode, reducing oxygen in the reaction.

Advantages of fuel cells:

1. Fuel cell have higher efficiency than diesel or gas engine.

2. most fuel cells operate silently compared to internal combustion engines, they are therefore ideally suited for use within buildings such as hospitals.

3. Fuel cells can eliminate pollution caused by burning fossil fuels, for hydrogen fuelled fuel cells the only by-product at point of use is water.

4. If the hydrogen comes from the electrolysis of water driven by renewable energy, then using fuel cells eliminates greenhouse gases over the whole cycle.

5. Fuel cells do not need conventional fuels such as oil or gas and can therefore reduce economic dependence on oil producing countries creating greater energy security for the user nation.