Hydrogen
Electricity can split water into hydrogen and oxygen.
- Complexity
- Very High
- Best suited for
- Industrial, research and commercial energy-storage applications
- Scale
- Commercial · Industrial
Overview
Electrolysis uses electricity to split water into hydrogen and oxygen. When the electricity comes from renewable generation, the resulting hydrogen carries no combustion emissions at point of use.
Hydrogen is easy to describe and hard to handle. The difficulty is not making it — it is compressing, storing and using it safely. Storage is a certified pressure-vessel discipline, not a workshop project.
Key consideration
Compression and storage — not production — are the limiting technical and regulatory factors.
Inputs & outputs
Feedstocks in
- Water
- Electricity
Fuel out
- Hydrogen
- Oxygen
How it works
- 1Renewable electricity
- 2Electrolyser
- 3Hydrogen gas
- 4Drying and purification
- 5Certified compression and storage
- 6Fuel cell or engine
Conceptual diagram. Real systems include control, monitoring and safety equipment at every stage.
What can it power?
Equipment categories
- Water treatment and deionisation
- Electrolyser stack and power electronics
- Gas drying and purification
- Certified compression equipment
- Certified pressure storage
- Hydrogen leak detection and ventilation
- Fuel cell or engine interface
Described at a category level. Equipment should be professionally specified, certified and installed.
Cost profile
Startup
Very High
Operating
High
Feedstock
Purchased electricity
Relative categories only. Real costs depend heavily on scale, equipment and local conditions.
Efficiency
Each conversion step loses energy. Electricity to hydrogen, then compression, then hydrogen back to motion through a fuel cell, results in a round-trip efficiency well below charging a battery directly with the same electricity.
Pros & limitations
Advantages
- No carbon emissions at point of use
- Fast refuelling relative to battery charging
- Useful for long-duration or seasonal energy storage
- Feedstock is water and electricity
Limitations
- Poor round-trip efficiency versus batteries
- Very high equipment cost
- Storage requires certified high-pressure or cryogenic systems
- Almost no consumer refuelling infrastructure
Vehicle compatibility
Never assume compatibility. Verify with the engine or equipment manufacturer before use.
Storage
Hydrogen is stored at very high pressure or cryogenically, using certified vessels, valves and fittings. It embrittles some metals and leaks through seals that would hold other gases.
Safety & Regulations
Safety considerations
- Extremely wide flammability range and very low ignition energy
- Burns with an almost invisible flame
- High-pressure systems must use certified components and inspection regimes
- Requires dedicated leak detection and ventilation design
Legal & regulatory
- Pressure-vessel codes and periodic inspection
- Fire code and separation distance requirements
- Electrical installation standards for electrolysers
- Vehicle fuel-system certification for road use
Requirements vary by jurisdiction and fuel type. Verify applicable rules before producing, storing, selling or using fuel. Use certified equipment and qualified professionals.