When this article was first published in December 2020, the 13 gigawatt-scale green hydrogen projects on this list added up to 50GW, out of a global pipeline of 80GW.

But this is a fast-moving sector, with new projects being announced on an almost daily basis. Now, less than four months later, the gigawatt-scale pipeline alone adds up to 137.8GW across 20 projects.

And this list will undoubtedly grow in the coming weeks and months as more companies seek to get an early foot in the door of what is expected to be an enormous and potentially lucrative new sector. Let's not forget that despite the massive potential for green hydrogen to decarbonise transport, heating and heavy industry, this is still a nascent sector — the largest electrolyser currently in operation is only 20MW.

The thinking behind leaping from megawatt-scale to gigawatt-scale is that the future demand for green H2 will be gigantic, and that costs can be quickly driven down through economies of scale, with a view to making renewable hydrogen cheaper than highly polluting grey (produced from unabated natural gas or coal) by 2030.

After all, roughly 70 million tonnes of grey hydrogen is produced each year, largely for use in ammonia fertiliser production and oil refining, emitting about 830 million tonnes of CO2 annually — the equivalent of the combined emissions of the UK and Indonesia. And grey hydrogen is currently two to six times cheaper than green.

So here are the world’s 18 biggest green-hydrogen projects now under development. Of course, whether all these projects ever get built is another matter.

1) HyDeal Ambition (67GW)

Location: Multiple sites across Western Europe, starting in Spain and southwest France, then extending to eastern France and Germany

Power source: 95GW of solar across multiple locations to power 67GW of electrolysers

Developers: A group of 30 energy players, including gas distributors Snam, Enagás and OGE; electrolyser maker McPhy; EPC provider Vinci Construction; and solar developers Falck Renewables and Qair.

Planned use of H2: To deliver green hydrogen across Europe at €1.50/kg before 2030 (ie, to be cheaper than unabated grey hydrogen)

H2 output: 3.6 million tonnes per year

Planned date of completion: Before 2030

Expected cost: Not stated

Stage of development: Early stage, project was announced in February 2021, although a "first initiative [is] expected within a year in Spain, based on a portfolio of solar sites with a capacity close to 10GW", according to McPhy.

2) Asian Renewable Energy Hub (14GW)

Location: Pilbara, Western Australia

Power source: 16GW of onshore wind and 10GW of solar to power 14GW of electrolysers

Developers: InterContinental Energy, CWP Energy Asia, Vestas, Macquarie

Planned use of H2: Green hydrogen and green ammonia for export to Asia

H2 output: 1.75 million tonnes per year (which would produce 9.9 million tonnes of green ammonia)

Planned date of completion: 2027-28

Expected cost: $36bn

Stage of development: Federal government has awarded AREH “major project status”, which will help to fast-track the project through permitting. State-level environmental approval had been given for a now-scrapped 15GW version of the project (which was to export electrons to Indonesia and Singapore), the developers are now submitting a second application for the 26GW project, which includes green ammonia facilities and the construction of a new town to house workers in remote north Western Australia.

3=) NortH2 (at least 10GW)

Location: Eemshaven, northern Netherlands

Power source: Offshore wind

Developers: Shell, Equinor, RWE, Gasunie, Groningen Seaports

Planned use of H2: To help power heavy industry in the Netherlands and Germany

H2 output: One million tonnes per year

Planned date of completion: 2040 (1GW by 2027, 4GW by 2030)

Expected cost: Not stated

Stage of development: Feasibility study under way, to be completed by July 2021

3=) AquaVentus (10GW)

Location: Heligoland, Germany

Power source: Offshore wind

Developers: A consortium of 47 companies, research institutions and organisations, including RWE, Vattenfall, Shell, E.ON, Siemens Energy, Siemens Gamesa, Vestas, Northland Power, Gasunie and Parkwind

Planned use of H2: General sale via a European hydrogen network

H2 output: One million tonnes per year

Planned date of completion: 2035 (30MW by 2025, 5GW by 2030)

Expected cost: Not stated

Stage of development: Early stage, project was only announced in August

5) HyEnergy Zero Carbon Hydrogen (8GW)

Location: The Gascoyne region of Western Australia

Power source: Wind and solar

Developer: Province Resources

Planned use of H2: Green hydrogen and ammonia "for heavy transport and industry", and potentially for blending into a local natural-gas pipeline. And later on, for export to Asian markets

H2 output: Not stated

Expected cost: Not stated

Planned date of completion: 2030

Stage of development: Early stage, project announced in February 2021

6=) Murchison Renewable Hydrogen Project (5GW)

Location: near Kalbarri, Western Australia

Power source: Onshore wind and solar

Developers: Hydrogen Renewables Australia and Copenhagen Infrastructure Partners

Planned use of H2: A demonstration phase would provide H2 for transport fuels; an expansion stage would produce H2 to blend into local natural-gas pipelines; and a final, large expansion would produce H2 for export to Asia, with a focus on Japan and South Korea

H2 output: not stated

Planned date of completion: 2028

Expected cost: $10-12bn

Stage of development: Early stage

6=) Beijing Jingneng Inner Mongolia (5GW)

Location: Eqianqi, Inner Mongolia, China

Power source: Onshore wind and solar

Developer: Chinese utility Beijing Jingneng

Planned use of H2: Not known

H2 output: 400,000-500,000 tonnes per year

Planned date of completion: 2021

Expected cost: $3bn

Stage of development: Due to be under construction this year, but not confirmed

8) Helios Green Fuels Project (4GW)

Location: Neom, a planned city in northwest Saudi Arabia

Power source: Onshore wind and solar

Developers: Air Products, ACWA Power, Neom

Planned use of H2: To produce green ammonia (NH4), which would be transported around the world and converted back into H2 for use as a transport fuel.

H2 output: About 240,000 tonnes per year (to create 1.2 million tonnes of green ammonia annually)

Planned date of completion: Not stated, but first ammonia production due in 2025

Expected cost: $5bn

Stage of development: Early stage, project was announced in July 2020

9) Pacific Solar Hydrogen (3.6GW)

Location: Callide, Queensland, Australia

Power source: Solar

Developer: Austrom Hydrogen, a start-up

Planned use of H2: Export to Japan and South Korea

H2 output: More than 200,000 tonnes per year

Planned date of completion: Not stated

Expected cost: Not stated

Stage of development: Early stage, project was announced in June 2020

10) Base One (3.4GW)

Location: Pecém, Ceará state, northeast Brazil

Power source: "Combined baseload wind and solar power"

Developer: Enegix Energy, in conjunction with Italian wind turbine maker Enerwind, EPC provider Black & Veatch, and the Ceará state government

Planned use of H2: Green hydrogen for "major international markets via ocean freight"

H2 output: 600,000 tonnes per year

Planned date of completion: 2025

Expected cost: $5.4bn

Stage of development: Project was announced on 1 March, but Enegix says it has "contracted" the 3.4GW of solar and wind capacity through its partnership with Enerwind

11) H2-Hub Gladstone (3GW)

Location: Gladstone, Queensland, Australia

Power source: Renewable energy, but not otherwise specified

Developer: The Hydrogen Utility (also known as H2U)

Planned use of H2: Green ammonia for export to Japan and other countries

H2 output: Not stated, but developer says it would produce “up to 5,000 tonnes of green ammonia per day”

Expected cost: $1.6bn (not including sources of power)

Planned date of completion: Not stated, but initial operations due to begin in 2025

Stage of development: Feasibility study under way, targeting approvals by 2023

12) Yellow Sea (2GW)

Location: Qingdao, Shandong province, China

Power source: Floating wind

Developers: Qingdao Blue Valley Industrial Development Zone, Shandong Zhongneng Integration Offshore Wind Turbine Manufacturing Corp (an affiliate of Fujian-based vertical-axis wind turbine maker Tonex) and PowerChina’s North West Engineering Institute

Planned use of H2: Not stated

H2 output: Not stated

Expected cost: Not stated

Planned date of completion: Not stated

Stage of development: Very early — the only concrete development so far seems to be a signed co-operation contract between the three co-developers

13) HyEx (1.6GW)

Location: Antofagasta, Chile

Power source: Solar

Developers: Engie and Enaex

Planned use of H2: Green ammonia, half of which will be used at Enaex’s ammonium nitrate plant; the remainder will be targeted for fuel, green fertiliser and export markets.

H2 output: 124,000 tonnes per year (700,000 tonnes of green ammonia)

Expected cost: Not stated

Planned date of completion: 2020 (26MW pilot by 2024)

Stage of development: Early stage, project was announced in October 2020

14) Geraldton (1.5GW)

Location: Geraldton, Western Australia

Power source: Onshore wind and solar

Developer: BP/BP Lightsource

Planned use of H2: Production of green ammonia for domestic and export markets

H2 output: Not stated, but about one million tonnes of green ammonia per year

Expected cost: Not stated

Planned date of completion: Not stated

Stage of development: Feasibility study under way

15) HNH (1.4GW)

Location: Southern Chile

Power source: 1.8-2GW of onshore wind to power 1.4GW of electrolysers connected to a Haber-Bosch system for ammonia production

Developers: AustriaEnergy and Ökowind EE

Planned use of H2: Green ammonia for export via a new international port (which is part of the project)

H2 output: 850,000 to one million tonnes of green ammonia per year

Expected cost: $3bn

Planned date of completion: 2026

Stage of development: Wind measurements are under way, topography studies have been done and work on enviromental licence application and wind farm design have begun

16) Greater Copenhagen (1.3GW)

Location: Greater Copenhagen area, Denmark

Power source: Offshore wind preferred

Developers: Orsted, Maersk, DSV Panalpina, DFDS, SAS

Planned use of H2: Hydrogen for buses and trucks, e-fuel (derived from green hydrogen and captured CO2) for shipping and aviation

H2 output: Not stated, but it would produce “250,000 tonnes of sustainable fuel” per year.

Expected cost: Not stated

Planned date of completion: 2030 (10MW pilot as soon as 2023, 250MW by 2027)

Stage of development: Feasibility study under way, with a view to a final investment decision in 2021

17=) SeaH2Land (1GW)

Location: Industrial clusters near North Sea ports in the Netherlands and Belgium

Power source: A 2GW offshore wind farm in the Dutch North Sea powering 1GW of electrolysers

Developers: Orsted, in conjunction with ArcelorMittal, Yara, Dow Benelux and Zeeland Refinery

Planned use of H2: For use at industrial clusters for the production of steel, ammonia, ethylene and transport fuel

H2 output: Not stated, but the industrial clusters currently consume 580,000 tonnes of grey hydrogen annually

Expected cost: Not stated

Planned date of completion: 2030

Stage of development: Early stage, project was announced at the end of March 2021

17=) Esbjerg (1GW)

Location: Esbjerg, Denmark

Power source: Offshore wind

Developer: Copenhagen Infrastructure Partners,in conjunction with shipping giants Moller-Maersk and DFDS, and food companies Arla, Danish Crown and DLG

Planned use of H2: Green ammonia for fertiliser production and as a shipping fuel.

H2 output: Not stated

Expected cost: Not stated

Planned date of completion: Between 2025 and 2027

Stage of development: Early stage, announced in February 2021

17=) H2 Sines (1GW)

Location: Sines, southwest Portugal

Power source: Undecided, but likely to be onshore wind and solar

Developers: EDP, Galp, Martifer, REN, Vestas

Planned use of H2: Domestic consumption and export

H2 output: Not stated

Expected cost: €1.5bn ($1.84bn)

Planned date of completion: 2030

Stage of development: Feasibility study under way

17=) Rostock (1GW)

Location: Rostock, Germany

Power source: Offshore wind and other renewable sources

Developer: Consortium led by RWE

Planned use of H2: All avenues being explored

H2 output: Not stated

Expected cost: Not stated

Planned date of completion: Not stated

Stage of development: Very early stage