Advanced Topic 1065 of 1102 Biochemistry, Environment & Industry

Green Hydrogen

Hydrogen produced by electrolysis powered by renewable electricity.

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In-depth explanation of Green Hydrogen

Green hydrogen is hydrogen produced by splitting water with electricity from renewable sources, so that its production emits no CO2. Water electrolysis releases H2 at the cathode and O2 at the anode, in alkaline, PEM or solid oxide electrolysers. Grey hydrogen is made from natural gas by steam methane reforming and emits CO2, while blue hydrogen adds carbon capture to reduce those emissions. Green hydrogen is a key option for decarbonising steelmaking, ammonia production, long-distance shipping and heavy transport. Its cost depends mainly on electricity price and electrolyser efficiency.

Going deeper: Green Hydrogen

Key ideas: Hydrogen made by water electrolysis (2H2O gives 2H2 plus O2) powered by renewable electricity. Theoretical minimum is 1.23 V and about 39.4 kWh per kg, real electrolyzers use about 50 to 55 kWh per kg. Types: alkaline, PEM, solid oxide. Gray hydrogen comes from steam methane reforming (CO2 emitted), blue adds carbon capture.

Common mistakes and connections: Mistake: calling hydrogen an energy source; it is an energy carrier. Low volumetric energy density requires compression to 700 bar or liquefaction at minus 253 C. Round-trip efficiency is only about 30 to 40 percent. Links to electrolysis, fuel cells, and ammonia as a carrier.

Visualization of Green Hydrogen

Water electrolysis splits water into hydrogen at the cathode and oxygen at the anode, powered by renewable electricity to make green hydrogen. The interactive lesson shows this as a live animation or chart.

Worked example and use case

An electrolyser needs roughly 50 kWh of electricity to produce 1 kg of hydrogen.

Frequently asked questions about Green Hydrogen

What is Green Hydrogen?

Hydrogen produced by electrolysis powered by renewable electricity.

Is Green Hydrogen a beginner, intermediate or advanced topic?

Green Hydrogen is a advanced topic in Biochemistry, Environment & Industry. It builds on beginner and intermediate topics, so review those first if needed.

What should I learn before Green Hydrogen?

Study these earlier topics in Biochemistry, Environment & Industry first: Carbon Capture, Renewable Energy Chemistry, Solar Cells.

What comes after Green Hydrogen?

The next topics in Biochemistry, Environment & Industry are Nuclear Power and Nuclear Waste.

Can I practise Green Hydrogen with quizzes?

Yes. The interactive lesson includes a self-check question on Green Hydrogen, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.

Where Green Hydrogen fits in Biochemistry, Environment & Industry

Green Hydrogen is topic 90 of 127 in Biochemistry, Environment & Industry.