As India launches the world’s longest hydrogen train and scales pilot projects across road and rail, green hydrogen is fast emerging as the fuel that could transform the country’s transport and industrial sectors. This article explores India’s growing green hydrogen ecosystem, examining hydrogen-powered trains, H₂-ICE and H₂-FCEV technologies, pilot projects, and the path towards clean mobility.
The global aim towards net-zero emissions is to reduce greenhouse gas (GHG) emissions - the gases that trap heat in the atmosphere and drive climate change - by 55 per cent by 2030. Similarly, as part of India’s energy transition towards green hydrogen technology, India will become the next big green hydrogen producer and exporter across the world, and it is truly a land of opportunity for green hydrogen by 2050. Green hydrogen is emerging as a key driver of the energy transition. Its versatility spans electricity, heating, transport, and industry, and it offers a decarbonisation pathway for hard-to-electrify sectors such as steel and logistics - industries where simply switching to electric power is not yet practical or economical.
Green hydrogen production only becomes sustainable when powered by renewable energy sources. Currently, low-emission hydrogen production remains under 1 Mt (one million tonnes) globally - a small fraction of overall hydrogen output, most of which is still produced from fossil fuels.
India is aiming to achieve its net-zero mission by 2070, for which renewable energy and hydrogen energy are becoming central spheres of attraction in the country’s energy transition movement.
Transport is a significant contributor to India’s greenhouse gas emissions and harmful particulate emissions - fine particles released by vehicles that affect air quality - which impact the health of cities, pollute the environment, and affect regional communities.
Hydrogen is a versatile, zero-emissions fuel that can be locally manufactured from waste materials, water, hydrocarbons, and other feedstocks using renewable electricity to make green hydrogen. The industry is in its infancy and relies to some extent on government support for pilot projects and trials. The sector is working towards clean, economical, and safe hydrogen production and distribution for widespread use in transport, stationary power, energy storage, and industrial purposes, including green ammonia and gas blending.
India’s first hydrogen passenger train - and the world’s longest hydrogen train - was recently launched on 17 July by the Hon’ble Prime Minister of India. This is an exciting development, using hydrogen as a clean energy carrier (‘green hydrogen’) to replace fossil fuels in hard-to-abate sectors, including transport. In simple terms, hydrogen acts as a fuel that powers the train without producing any carbon dioxide, making it one of the cleanest forms of rail transport available today. This could provide a viable path to achieving net-zero GHG emissions targets, while also enabling a range of co-benefits for the Indian economy.
There are two common types of technologies that use hydrogen as fuel for transport: H₂-ICE (Hydrogen Internal Combustion Engine) and H₂-FCEV (Hydrogen Fuel Cell Electric Vehicle). In simple terms, H₂-ICE burns hydrogen to generate power - much like a petrol or diesel engine - while H₂-FCEV uses a chemical reaction between hydrogen and oxygen to generate electricity, which then drives an electric motor.
H₂-ICE vehicles burn hydrogen in an internal combustion engine, like petrol or diesel in a conventional engine. Hydrogen is easier to ignite than petrol or diesel and requires direct injection - a method of delivering fuel directly into the engine cylinder at high pressure - to manage the risk of backfiring (unintended ignition). Hydrogen also needs more oxygen to burn all the fuel. The properties of hydrogen and air affect the ignition process, and this leads to nitric oxide (NOx) emissions - a pollutant that can cause respiratory issues and smog - which need to be handled through an additional exhaust treatment process in existing engines. However, hydrogen has a wide flammability range of 4–75 per cent, meaning it can ignite across a broad range of fuel-to-air mixtures, enabling the engine to burn it effectively when mixed with air in the right proportion. In the H₂-ICE, a hydrogen concentration greater than 5 per cent enables higher efficiency compared to a diesel-fuelled engine. Hydrogen is therefore considered a highly potential and efficient future clean fuel with zero CO₂ emissions, which will help globally to meet emission standards and regulations. Similarly, hydrogen helps reduce global dependence on fossil fuel resources and will decrease the level of exhaust emitted by vehicle engines.
The CO₂ emissions from hydrogen depend on the production method. Steam methane reforming - a process that extracts hydrogen from natural gas - emits CO₂, while water electrolysis - splitting water into hydrogen and oxygen using electricity - does not emit CO₂. However, electrolysis requires significant electricity input to split water into H₂ and O₂ ions, making it more expensive compared to other methods. Worldwide, H₂-ICE and H₂-FCEV are the most prominent emerging technologies for commercialising hydrogen as a fuel and contributing to India’s and the global net-zero mission by reducing CO₂ emissions. With reference to current studies and practical field demonstrations and simulations by different OEMs (original equipment manufacturers - the companies that design and build vehicles), it is observed that H₂-ICE engine material compatibility is stringent in tolerating different fuels, but it has greater tolerance to contamination, mature ICE technology, reduced consumption of scarce materials, and easier adoption to run on hydrogen with slight modification - compared to H₂-FCEV - for light and heavy-duty vehicles.
An H₂-FCEV is propelled by one or more electric motors powered by electricity generated on board by a hydrogen fuel cell - a device that combines hydrogen and oxygen through a chemical reaction to produce electricity, with water as the only by-product. Energy is stored in hydrogen tanks on board the vehicle, and the tanks need to be refuelled at a hydrogen refuelling station. Hydrogen vehicles also need smaller batteries to manage the power load, but have the advantage of faster refuelling times and the ability to refuel in a manner similar to diesel.
H₂-FCEV vehicles use a different process - combining hydrogen with oxygen and passing it through a proton exchange membrane (PEM) fuel cell to create electricity. The PEM is essentially a special polymer membrane that allows only protons (hydrogen ions) to pass through, facilitating the electrochemical reaction that generates power. There are several different types of fuel cells; however, for vehicles, only the proton-exchange membrane is viable, as the others generate too much heat and are generally used for stationary storage and power generation. Although H₂-FCEV and H₂-ICE may seem like competing technologies, both drive the development of a common hydrogen production, transportation, and distribution infrastructure and share the same vehicle storage tanks. They are complementary technologies that can enable the use of hydrogen in the transport sector. H₂-ICE technology is more preferable in the initial stage of technology commercialisation in the Asian region, including India. H₂-FCEV, which incurs higher capital expenditure, is the best option for heavy-duty and long-distance vehicles, including intercity buses.
The performance, efficiency, and NOx emission levels of hydrogen-powered IC engines depend on the method of hydrogen injection - that is, how and where hydrogen is introduced into the engine. There are two methods: Port Fuel Injection (PFI), where hydrogen is mixed with air before entering the cylinder, and Direct Injection (DI), where hydrogen is injected directly into the cylinder at high pressure just before combustion. The DI method improves efficiency and lowers emissions in H₂-ICE vehicles compared to PFI, because it gives more precise control over the fuel-air mixture. Therefore, with necessary slight modifications to the ICE engine, H₂-ICE technology can power vehicles with higher efficiency and lower emissions than diesel engine vehicles, making it one of the most attractive solutions and a preferred choice in India’s automotive sector. Hydrogen can thus be a strong alternative fuel for both internal combustion engines and fuel cell engines.
Regarding the cost gap between H₂-FCEVs and H₂-ICEVs, H₂-ICEV technology will contribute significantly because it is easier for end users to adopt, has lower emissions, and is more efficient. Hydrogen can be used in both compression ignition (where fuel ignites under pressure, as in a diesel engine) and spark ignition (where a spark plug triggers combustion, as in a petrol engine) with light modifications to conventional IC engines.
Serial production of H₂-ICEVs has not yet begun, as the hydrogen refuelling infrastructure required to support both fuel cell electric vehicles (FCEVs) and hydrogen-fuelled internal combustion engine vehicles (H₂-ICEVs) is not yet in place.
In India, at pilot scale - meaning small-scale real-world trials before full commercial rollout - H₂-ICEVs and H₂-FCEVs, including trucks, buses, and trains, have already been successfully demonstrated and are in trial operation, along with refuelling infrastructure with a green hydrogen storage capacity of 3,000 kg per annum. This will be a driving force for OEMs and end users to commercialise the technology, with higher efficiency and greater driving range vehicles in India soon.
Green hydrogen is predicted to become the lowest-cost production option in the future, given rising natural gas costs and the very real potential for carbon costs to be imposed soon. It is produced using renewable energy and water through an electrolyser - a device that uses electricity to split water molecules into hydrogen and oxygen - to split hydrogen from water. The cost of hydrogen production varies significantly across different regions, depending on energy input costs, availability of appropriate options for carbon capture and storage (CCS) - a technology that captures CO₂ before it enters the atmosphere and stores it underground - and access to land and water resources. Electricity is the largest cost component, which is why low-cost renewables at scale are required to make the industry work at a larger scale and contribute to India’s hydrogen economy.
About the Author
Dr Shabana Shaikh holds a PhD in Physics with specialisation in Materials Science and Engineering. She brings a unique combination of deep technical knowledge and commercial leadership, with over 19 years of professional experience in renewable and clean energy technologies, particularly hydrogen production, fuel cell systems, and hydrogen mobility. Her experience extends across the entire value chain - from R&D and prototyping to infrastructure planning, supply chain development, project planning, project execution, QC management, product development, and market deployment. She has prepared stringent safety testing protocols for hydrogen fuel system leak tightness and is an active expert panel member for Indian national standards bodies including BIS, ARAI, and AIS. She has conceptualised and delivered commercially viable projects including India’s first H₂-powered train, H₂-ICE trucks, H₂-FC trucks, H₂-buses, and H₂ generation and storage plants.