What are the advantages and disadvantages of using hydrogen as a fuel?

In one line

The rule

Hydrogen is a clean fuel that, when used in a fuel cell, produces only water, electricity, and heat as byproducts. (NCERT Class 12)

Let's understand it simply

Imagine you have a magic fuel that, when you burn it, gives you energy and only water comes out—no smoke, no bad smell. That’s what hydrogen does. Think of a pressure cooker: if you use hydrogen to heat it, the steam coming out is just water vapor, not dirty smoke like burning coal or wood. But, just like a balloon filled with gas can burst, hydrogen is tricky to store and can be dangerous if not handled properly.

How it works

1. Hydrogen is stored in tanks, often under high pressure.
2. In a fuel cell, hydrogen reacts with oxygen from the air.
3. This reaction splits hydrogen into protons and electrons.
4. Electrons flow through a wire, making electricity.
5. Protons and electrons meet oxygen to form water.
6. The only byproducts are water and heat—no pollution.

The story behind it

Hydrogen was first used as a fuel in balloons and airships in the 1800s. Scientists like William Grove in 1839 invented the first fuel cell, showing hydrogen could make electricity. The biggest push came when NASA used hydrogen fuel cells to power Apollo spacecraft, giving astronauts clean water and electricity in space.

Where you see it in real life

• Hydrogen fuel cell cars: Some cars run on hydrogen, giving out only water from the exhaust.
• Rockets: ISRO and NASA rockets use liquid hydrogen as fuel because it gives a lot of energy.
• Power backup: Hospitals and data centers use hydrogen fuel cells for emergency electricity.
• Buses in Delhi: Some city buses are being tested with hydrogen fuel cells to reduce pollution.
• Factories: Hydrogen is used to make fertilizers and clean metals.
• Remote villages: Small hydrogen fuel cells can power homes where electricity wires cannot reach.

Why it matters

• Reduces pollution: No smoke, no carbon dioxide—just water.
• Energy security: We can make hydrogen from water using sunlight or wind, so we don’t depend on coal or oil.
• High efficiency: Hydrogen fuel cells can be more efficient than petrol engines.
• Future jobs: New industries and jobs in making, storing, and using hydrogen.

Advantages

1. Clean byproduct: Only water is produced, so it doesn’t pollute the air.
2. Abundant: Hydrogen is the most common element in the universe.
3. High energy content: 1 kg of hydrogen has almost 3 times more energy than 1 kg of petrol.
4. Renewable: Can be made from water using solar or wind power.
5. Silent operation: Fuel cells are quiet, unlike diesel generators.

Disadvantages

1. Storage is hard: Hydrogen is a light gas and needs to be stored under high pressure or very cold temperatures.
2. Safety risks: It is highly flammable and can explode if leaked (like a leaking LPG cylinder, but even lighter).
3. Expensive: Making, storing, and transporting hydrogen costs more than petrol or diesel today.
4. Not found freely: Hydrogen is always combined with other elements (like in water), so it takes energy to separate it.
5. Few refueling stations: Not many places to fill up hydrogen, unlike petrol pumps.

Worked example

Let’s compare energy from 1 kg of hydrogen and 1 kg of petrol:

Given: 1 kg hydrogen = 120 MJ (megajoules), 1 kg petrol = 44 MJ
Step 1: Write the comparison      Hydrogen energy / Petrol energy
Step 2: Put in the numbers        120 MJ / 44 MJ
Step 3: Answer                    Hydrogen gives about 2.7 times more energy per kg than petrol

Common mistakes

• Thinking hydrogen is found as a gas in nature: It’s always part of water or other compounds; we must separate it.
• Believing it is always safe: Hydrogen is very flammable and needs careful handling.
• Assuming it is cheap: Right now, hydrogen fuel is more expensive than petrol or diesel.
• Ignoring infrastructure: Few hydrogen stations exist, so it’s not easy to use everywhere yet.

Remember it

Hydrogen fuel is clean and powerful, but storing and using it safely is the biggest challenge.