Hydrogen

Please note: This article is for educational purposes only. Always consult a qualified energy engineer before making any decisions about hydrogen systems for your business.

Hydrogen is a promising alternative fuel that offers clean energy with the potential to significantly reduce greenhouse gas emissions across transportation, industry, and energy storage. Its high energy-to-weight ratio makes it particularly suited to long-range and high-energy applications, positioning it as a key technology in the transition to net zero.

Contents

1. What is Hydrogen as a Fuel?
2. Safety Risks and Considerations
3. Types of Hydrogen
   1. Grey Hydrogen
   2. Blue Hydrogen
   3. Green Hydrogen
4. Storage and Transportation
5. Applications of Hydrogen
   1. Renewable Energy Storage
   2. Heating
   3. Transportation and Vehicles
   4. Business and Industry

What is Hydrogen as a Fuel?

Hydrogen is a versatile energy carrier that can be used across transportation, industry, and energy storage. Ongoing technological advancements continue to improve its efficiency, durability, and cost-effectiveness. As part of the UK’s UK Hydrogen Strategy, hydrogen is increasingly recognised as a key tool for addressing climate change, improving air quality, and advancing sustainable energy solutions alongside other low-carbon technologies such as heat pumps and battery storage.

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Safety Risks and Considerations

Hydrogen has a number of potential risks that require comprehensive safety measures, regulations, and standards for safe production, storage, handling, and use:

• Hydrogen gas is highly flammable and exhibits a wide flammability range, making it prone to ignition across various concentrations when mixed with air.
• Its invisible flames make detection challenging, necessitating stringent safety measures for handling, storage, and transportation.
• Hydrogen has a low ignition energy, allowing it to ignite easily from small sparks or heat sources, presenting explosive hazards particularly in enclosed spaces.
• Hydrogen is colourless and odourless, making leak detection difficult. Odorising hydrogen is challenging and can contaminate technologies like fuel cells.

For further guidance on hydrogen safety, refer to the Health and Safety Executive’s hydrogen safety guidance.

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Types of Hydrogen

Grey Hydrogen

Grey hydrogen is the most common type, produced through steam methane reformation (SMR) using fossil fuels such as natural gas. In this process, methane and steam are heated at high temperatures to yield hydrogen and carbon dioxide. Each kilogram of hydrogen produced this way emits 8–12kg of CO₂, making it highly polluting and incompatible with net zero targets.

Blue Hydrogen

Blue hydrogen reduces carbon emissions compared to grey hydrogen by employing carbon capture, usage and storage (CCUS) technology to capture the CO₂ produced during production. Although storing CO₂ carries logistical challenges and costs, blue hydrogen is forecast to become one of the most cost-effective low-carbon hydrogen production methods in the future.

Green Hydrogen

Green hydrogen is derived from renewable sources such as wind or solar power via electrolysis, and boasts the lowest carbon emissions of all hydrogen production methods. However, producing 1 kg of hydrogen requires approximately 45 kWh of electricity, while the hydrogen itself contains only 33.6 kWh of usable energy — an efficiency gap that ongoing research is working to close.

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Storage and Transportation

At room temperature and pressure, hydrogen has a very low density. To store meaningful quantities, it must either be cooled to become a liquid or compressed. Both approaches require specialist infrastructure and careful safety management.

Hydrogen can utilise existing natural gas pipelines for long-distance transportation, which could facilitate easier distribution to small and medium businesses without the need for dedicated new infrastructure. However, challenges around material compatibility, leakage, and safety must be addressed before widespread pipeline transportation becomes viable.

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Applications of Hydrogen

Renewable Energy Storage

Renewable energy sources like solar and wind are growing rapidly but face challenges due to their intermittent nature. Excess renewable energy can be stored using hydrogen through power-to-gas technology, providing a flexible solution to meet constant energy demands when generation is low. This complements other storage approaches such as commercial battery storage systems.

Heating

Blending hydrogen with natural gas in boilers provides a pathway toward a lower-carbon heating system. Hydrogen boilers offer high efficiency, though safety considerations remain important, with ongoing industry efforts to ensure the safe deployment of hydrogen-blended gas systems across commercial buildings.

Transportation and Vehicles

Hydrogen fuel cell vehicles (FCVs) offer a clean transportation solution with zero harmful tailpipe emissions. Despite currently limited refuelling infrastructure, hydrogen shows significant promise for decarbonising heavy transportation modes including buses, trains, and ships, where battery solutions are less practical due to weight and range requirements. The UK Government’s Zero Emission HGV programme is actively exploring hydrogen as part of the solution for heavy goods vehicles.

Business and Industry

Hydrogen finds important applications in industrial processes including hydrogenation, metal processing, and ammonia production, offering cleaner alternatives to conventional fossil fuels. For UK manufacturers already navigating life cycle carbon reporting and emissions reduction obligations, hydrogen represents one of several decarbonisation pathways worth evaluating alongside electrification and energy efficiency measures.

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