Forum Institutional

Your guide to electrolysis: the tech behind the green hydrogen revolution

Green hydrogen has the potential to massively reduce emissions of industries including transportation and manfuacturing.

Green hydrogen has the potential to massively reduce emissions of industries including transportation and manfuacturing. Image: REUTERS/Thilo Schmuelgen

Sundus Cordelia Ramli
Chief Commercial Officer, Power-to-X, Topsoe
Our Impact
What's the World Economic Forum doing to accelerate action on Forum Institutional?
The Big Picture
Explore and monitor how Energy Transition is affecting economies, industries and global issues
A hand holding a looking glass by a lake
Crowdsource Innovation
Get involved with our crowdsourced digital platform to deliver impact at scale
Stay up to date:

Tech and Innovation

This article is part of: Centre for Energy and Materials

Listen to the article

  • Green hydrogen is widely regarded as a transformative fuel that could power the green transition.
  • The process by which it is made, electrolysis, is less understood.
  • Here's everything you need to know about electrolysis, and what it means for green hydrogen and the future of our planet.

In an era marked by growing environmental concerns and the urgent need to transition towards cleaner and more sustainable energy sources, electrolysis has emerged as a transformative technology with the potential to revolutionize the energy landscape. It is the technology that facilitates the creation of green hydrogen.

Electrolysis is a process that harnesses electrical energy to split water molecules into hydrogen and oxygen gases. When the process is powered by renewable energy, it can be used to create green hydrogen. That green hydrogen can then, in turn, be used as a clean energy carrier.

The potential of green hydrogen to decarbonize hard-to-abate industries — shipping, aviation, steel, cement and petrochemical production — is vast. In fact, these industries account for roughly 30% of all greenhouse gas emissions.

Here’s everything you need to know about the technology responsible for the green hydrogen revolution.

Have you read?

Electrolysis will provide these sectors with green hydrogen


Green hydrogen can be used in fuel cell vehicles, providing a zero-emission alternative to traditional internal combustion engines. Green ammonia and e-methanol, which are derivatives of green hydrogen, are currently being explored as key solutions in decarbonizing the world's industrial-scale transportation industries. This is particularly relevant in the global shipping industry, where there are projects set to be tested and developed as early as 2024.


Steel, cement and chemical production are among the industries with the highest level of emissions and, unfortunately, have the most difficulty in decarbonizing. This is partly due to the fact that many of the manufacturing processes across these industries require a large amount of energy to produce the high temperature heat needed for production. Luckily, these energy intensive processes can use green hydrogen as a substitute, opening up the possibility to produce products such as ‘green steel’ — where green hydrogen is used to generate heat and takes the place of coal and natural gas in facilitating chemical processes.

Energy storage

Green chemicals can also serve as energy storage mediums, allowing excess renewable energy from wind and solar to be stored and later converted back to electricity when needed. This helps stabilize the grid and supports the integration of intermittent renewable sources.


What's the World Economic Forum doing about the transition to clean energy?

3 types of electrolysis: what you need to know

Electrolysis is primarily achieved through three types of industrial technologies: high-temperature Solid-Oxide Electrolysis Cell (SOEC); low-temperature alkaline electrolysis; and low-temperature polymer electrolyte membrane (PEM) electrolysis. With alkaline and PEM electrolysis, water is supplied as a liquid, whereas SOEC electrolysis uses steam due to its high temperatures.

PEM electrolysis

PEM electrolysis uses a solid polymer electrolyte membrane to separate the hydrogen and oxygen gases. This membrane allows for high proton conductivity, a key process in the creation of green hydrogen, while preventing the mixing of gases. It operates at relatively low temperatures, between 50-80°C, and is known for its rapid response time.

PEM electrolysis systems are compact, modular and well-suited for intermittent renewable energy sources like wind and solar. They can quickly adjust their output to match fluctuations in energy supply.

PEM electrolysis systems tend to be more expensive due to the cost of the membrane material. The market for PEM electrolysis is well established, particularly in applications requiring high purity hydrogen, such as fuel cell vehicles for pipelines. The market is expected to grow as renewable energy adoption expands.

SOEC electrolysis

SOEC electrolysis employs a solid oxide ceramic electrolyte that operates at high temperature, typically around 675°C to 825°C. At these temperatures, the water electrolysis reaction is easier to drive, which in turn results in a lower power consumption per unit of hydrogen produced.

SOEC offers higher efficiency than PEM and alkaline electrolysis, and can make use of waste heat from industrial processes or concentrated solar power. It is well-suited to large-scale hydrogen production with uses including steel, ammonia and chemicals production and refining.

The International Renewable Energy Agency (IRENA) estimate that SOEC electrolysers are between 10-26% more efficient (by kWh per kg of hydrogen produced) than alkaline and PEM technologies.

SOEC electrolysis is a relatively nascent technology compared to PEM and alkaline for many applications. However, the technology holds promise for industrial and energy storage applications, especially where high-temperature heat sources and high heat-waste emissions are available.

Alkaline electrolysis

Alkaline electrolysis uses an alkaline electrolyte solution, usually potassium hydroxide, to facilitate the ion exchange process that makes hydrogen. It operates at moderate temperatures and has been used for decades in industrial applications.

Alkaline electrolysers are cost-effective and have a long history of commercial use. However, Alkaline electrolysis systems are less efficient and slower to respond to load changes compared to PEM electrolysis.

Alkaline electrolysis remains competitive in certain industrial sectors but may face challenges in terms of efficiency and adaptability to renewable energy integration.

The opportunity of electrolysis

A green energy economy will not be enabled through any one single idea or technology. However, electrolysers will be instrumental in creating green transitions for some of the world’s most carbon-intensive industries.

Green hydrogen is the bridge between a wind turbine, or a solar panel, to fuels we use in our everyday lives, in planes, in cars or in ships — and electrolysis maskes that happen.

The emerging green hydrogen economy presents substantial economic prospects, fostering job creation and driving innovation and investment in clean energy technologies, and bolsters energy security.

Continued research, innovation and investment in electrolysis is essential — it is a major opportunity that will reap dividends for those who act fast and for the planet itself.

Don't miss any update on this topic

Create a free account and access your personalized content collection with our latest publications and analyses.

Sign up for free

License and Republishing

World Economic Forum articles may be republished in accordance with the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License, and in accordance with our Terms of Use.

The views expressed in this article are those of the author alone and not the World Economic Forum.

Related topics:
Forum InstitutionalEnergy Transition
World Economic Forum logo
Global Agenda

The Agenda Weekly

A weekly update of the most important issues driving the global agenda

Subscribe today

You can unsubscribe at any time using the link in our emails. For more details, review our privacy policy.

AMNC24: Five things to know about the 'Summer Davos' in China

Gayle Markovitz

June 28, 2024

About Us



Partners & Members

  • Sign in
  • Join Us

Language Editions

Privacy Policy & Terms of Service

© 2024 World Economic Forum