How is green hydrogen produced?

In one line

The rule

Green hydrogen is hydrogen gas (H₂) produced by using renewable energy to split water (H₂O) through a process called electrolysis, without causing pollution.

The main formula for splitting water: 2H₂O (liquid) → 2H₂ (gas) + O₂ (gas)

Let's understand it simply

Imagine you have a pressure cooker filled with water. If you heat it, steam comes out. Now, imagine if you could use electricity, not heat, to break the water itself into two gases: hydrogen and oxygen. This is what happens in a process called electrolysis (breaking water using electricity).

But here’s the twist: If the electricity comes from coal or oil, it pollutes the air. If it comes from the sun (solar panels) or wind (windmills), it is clean and green. When we use only clean electricity, the hydrogen we get is called green hydrogen.

How it works

1. Collect clean electricity: Use solar panels, wind turbines, or hydropower to generate electricity without pollution.
2. Set up an electrolyser: This is a special machine with two rods (electrodes) placed in water.
3. Pass electricity through water: The electricity flows through the water, splitting it into hydrogen and oxygen gases.
4. Collect the gases: Hydrogen bubbles form at one rod (the cathode), and oxygen at the other (the anode).
5. Store the hydrogen: The hydrogen gas is collected, cleaned, and stored for later use as fuel or in factories.

The story behind it

The idea of splitting water with electricity was first shown by two British scientists, William Nicholson and Anthony Carlisle, in 1800. They used a simple battery to split water into hydrogen and oxygen. But back then, electricity came from coal, so it was not green. The push for green hydrogen started recently, as the world looks for ways to fight climate change and reduce pollution. Today, countries like India, Germany, and Japan are investing in green hydrogen to power buses, trains, and factories without harming the environment.

Where you see it in real life

• Solar-powered water splitting plants: In Rajasthan, solar panels power electrolysers to make green hydrogen.
• Wind farms in Gujarat: Wind turbines generate electricity, which is used to split water for green hydrogen.
• Hydrogen buses: Some cities are testing buses that run on green hydrogen, releasing only water vapor.
• Steel factories: Green hydrogen is used instead of coal to make steel, reducing pollution.
• Cooking gas: In the future, green hydrogen might be mixed with LPG for cleaner cooking.
• Hydrogen fuel stations: These stations fill up vehicles with green hydrogen instead of petrol or diesel.

Why it matters

• Fights air pollution: Green hydrogen does not release harmful gases like CO₂.
• Saves fossil fuels: It replaces coal, petrol, and diesel in many uses.
• Helps in climate change: Using green hydrogen cuts down greenhouse gases.
• Creates new jobs: Building and running green hydrogen plants gives work to many people.

Worked example

Let’s say you want to make 2 grams of hydrogen using electrolysis.

Given: 2H₂O (liquid) → 2H₂ (gas) + O₂ (gas)
Step 1: 2 moles of water give 2 moles of hydrogen gas.
Step 2: 1 mole of H₂ = 2 grams, so 2 moles = 4 grams.
Step 3: To get 2 grams of H₂, you need 1 mole of water (18 grams).
Step 4: Pass electricity through 18 grams of water using a solar-powered electrolyser.
Step 5: Collect 2 grams of hydrogen gas at the cathode.

Common mistakes

• Thinking all hydrogen is green: Most hydrogen today comes from coal or natural gas (not green).
• Forgetting the electricity source: Only hydrogen made with renewable electricity is truly green.
• Mixing up electrolysis with burning: Electrolysis splits water; burning hydrogen combines it with oxygen to make water again.
• Ignoring storage: Hydrogen is hard to store and transport; special tanks are needed.

Remember it

Green hydrogen = clean electricity + water + electrolysis → hydrogen gas, no pollution.