Green Hydrogen’s Promise and Limits in the Global Race to Net-Zero Energy

A new multi-institutional study finds that green hydrogen could play an important role in cutting emissions in hard-to-electrify sectors like heavy industry, shipping and long-distance transport. However, the researchers stress that hydrogen is not a universal solution and must be deployed strategically due to challenges related to cost, infrastructure, water use and energy efficiency.

Green hydrogen is increasingly being promoted as a key solution for reducing global carbon emissions. But a comprehensive new review by researchers from several Indian institutions argues that hydrogen should be used carefully and strategically rather than treated as a universal energy fix. The study was conducted by scientists from SRM University-AP, SRM Institute of Science and Technology, Visva-Bharati University, Sukanta Mahavidyalaya under the University of North Bengal, the Central University of Rajasthan, Vignan’s Foundation for Science Technology and Research, and the CSIR-Indian Institute of Petroleum. Their work examines hydrogen technologies through the perspectives of sustainability, green chemistry and circular economy principles, offering a balanced view of both the opportunities and the challenges.

Why Hydrogen Is Gaining Global Attention

The world still relies heavily on fossil fuels such as coal, oil and natural gas for energy. Even though renewable energy sources like solar and wind are expanding quickly, fossil fuels continue to dominate the global energy supply. At the same time, energy demand keeps growing due to population increases, urbanisation and industrial development. Hydrogen has therefore attracted attention as a cleaner alternative energy carrier.

When hydrogen is used in fuel cells or combustion systems, it produces water instead of carbon dioxide. This makes it appealing for reducing emissions in sectors where cutting carbon is difficult. Hydrogen can power heavy industries such as steel and chemicals, long-distance transport, including ships and trucks, and even aircraft in the future. It can also act as a storage system for renewable electricity. Excess power produced by wind or solar farms can be converted into hydrogen and used later when electricity demand increases.

Different Ways to Produce Hydrogen

Hydrogen can be produced in several ways, but not all methods are environmentally friendly. The most common type today is grey hydrogen, which is produced from fossil fuels using processes such as steam methane reforming. This method is widely used because it is cheap and mature, but it releases large amounts of carbon dioxide.

Blue hydrogen attempts to reduce these emissions by capturing and storing the carbon dioxide generated during production. However, the most sustainable option is green hydrogen. It is produced through electrolysis, a process that splits water into hydrogen and oxygen using electricity generated from renewable sources such as wind, solar or hydropower.

Researchers are also exploring other emerging production methods. Biological approaches use microorganisms to produce hydrogen from organic waste or biomass. Solar-driven technologies attempt to generate hydrogen directly from sunlight. Although these ideas are promising, most of them are still in experimental stages and not yet ready for large-scale commercial use.

Storage, Transport and Infrastructure Challenges

Producing hydrogen is only one part of the challenge. Because hydrogen has a very low energy density by volume, storing and transporting it efficiently is difficult. The gas can be compressed into high-pressure tanks, converted into a cryogenic liquid at extremely low temperatures, or stored within chemical compounds such as ammonia or metal hydrides.

Each storage method has advantages and drawbacks. Compressed hydrogen tanks are widely used in fuel-cell vehicles but require strong and expensive materials. Liquid hydrogen allows more energy to be stored in smaller volumes but needs complex refrigeration systems. Chemical storage systems can carry large amounts of hydrogen safely, but additional energy is needed to release the hydrogen when it is required.

Transporting hydrogen also requires specialised infrastructure such as pipelines, tanker trucks and ships. Building this infrastructure will require significant investment and careful planning, especially if hydrogen is to become a globally traded energy commodity.

Hydrogen’s Role in the Future Energy System

Hydrogen can also be converted back into electricity through fuel cells or hydrogen-powered turbines. In so-called power-to-hydrogen-to-power systems, renewable electricity can be transformed into hydrogen during periods of surplus energy production and converted back into electricity when demand rises. This makes hydrogen particularly useful for storing energy over long periods and balancing renewable energy systems.

However, these conversions involve energy losses at each stage, which means hydrogen systems are less efficient than using electricity directly. In addition, large-scale hydrogen production requires significant water resources and specialised materials such as platinum and iridium used in catalysts.

The researchers conclude that hydrogen could play an important role in achieving a low-carbon future, especially in industries and transport sectors that are difficult to electrify. But they emphasise that hydrogen should complement other clean energy solutions rather than replace them entirely. With careful planning, technological innovation and supportive government policies, green hydrogen could become a valuable part of the global effort to build a cleaner and more sustainable energy system.