Leading the
Green Hydrogen Revolution

The only way to succeed in our sustainable future is to partner with the best


A 100 Per Cent Renewable Energy Future Is Now a Reality

Discover how Sigma can help you and your organization be ready and profit from our decarbonized future with green hydrogen.

Sigma is setting the benchmark for hydrogen generation for the future. By 2030, we are expected to reach fossil fuel parity prices with green hydrogen, bringing it to a massive global scale.


The Future Is Now

The only net-zero fuel source is green hydrogen emitted by electrolysers and generated through renewable energy sources. With no negative impact on air quality while maintaining the earth’s existing water and oxygen balance.

The fuel of the future is just around the corner and the early adopters will be able to get massive first-mover advantages and become key market players. Several countries and industry sectors have completely pledged to achieve net zero emissions, green hydrogen is the fuel of now.


Explore Solutions by Industry

Discover how Sigma can help you and your organization be ready and profit from our decarbonized future with green hydrogen.


Sigma is enabling real change

If you want to join the green hydrogen revolution, Sigma is here for you regardless of the size of your enterprise. Whether you are an investor, a small enterprise, a large-scale industry, or a corporation we can assist you.


Frequently Asked Questions

Common questions on hydrogen and its applications

What is hydrogen?
It is the most abundant chemical element, accounting for 75% of the universe's mass. It is colorless, odorless, tasteless, non-toxic, and highly combustible.
Is hydrogen an unusual element?
The element hydrogen constitutes the majority of the universe and powers our stars, but it is scarce on Earth. Hydrogen is the lightest gas and element in the universe, as well as the most abundant.
What temperature causes hydrogen gas to become liquid?
When hydrogen is cooled below -252.87 °C, it condenses into a liquid. Liquid hydrogen has a density of approximately 71 kg/m3 at -252.87°C and 1.013 bar.
What is the energy content of hydrogen in comparison to other fuels?
The energy content of 2.2 pounds (1 kilogram) of hydrogen gas is roughly equivalent to the energy content of 1 gallon (6.2 pounds, 2.8 kilograms) of gasoline. Because hydrogen has a low volumetric energy density, it is stored as a compressed gas onboard a vehicle to provide the driving range of conventional vehicles.
How can hydrogen's stored energy be used?
Hydrogen fuels vehicles, generate electricity, powers industry, and heats our homes and businesses. It has the potential to significantly reduce our carbon footprint and will be critical to achieving net zero emissions.
Do we have sufficient experience producing and utilizing hydrogen?
For more than 200 years, hydrogen has been produced and used. Experience has shown that hydrogen can be safely stored, distributed, and converted. The first large-scale use of hydrogen was established for the London street lighting system in 1808.
How is hydrogen produced?
Hydrogen can be produced using a variety of domestic resources, such as fossil fuels, biomass, and water electrolysis with electricity. The impact on the environment and energy efficiency of hydrogen is determined by the method by which it is produced.
What methods of producing hydrogen are available today?
A variety of processes can be used to produce hydrogen. Heat and chemical reactions are used in thermochemical processes to extract hydrogen from organic materials such as fossil fuels and biomass, as well as from inorganic materials such as water. Using electrolysis or solar energy, water (H2O) can also be split into hydrogen (H2) and oxygen (O2). Through biological processes, microorganisms such as bacteria and algae can produce hydrogen.
How is hydrogen stored?
Hydrogen can be physically held as a gas or a liquid. High-pressure tanks are often required for storing hydrogen as a gas (350–700 bar [5,000–10,000 psi] tank pressure). Because the boiling point of hydrogen at one atmospheric pressure is 252.8°C, storing it as a liquid necessitates cryogenic temperatures.
Why is hydrogen compression or liquefaction required?
Reducing the energy required for H2 compression, cooling, or liquefaction for storage can help to reduce hydrogen vehicles' upstream energy consumption. Overpressures are required to obtain a complete fill while rapidly refilling with high-pressure H2 gas due to compression heating.
What are the most prevalent pressures in compressed gas storage?
The majority of compressed gas cylinders, whether ultra-high purity or industrial grade, are pressured to roughly 2000 psi. This is a massive quantity of potential energy.
How does hydrogen get from point A to point B?
Hydrogen is carried by pipeline and over the road in cryogenic liquid tanker trucks or gaseous tube trailers from the site of production to the point of usage. Pipelines are being built in areas with high demand that is expected to last for decades.
Is hydrogen harmful or toxic?
Hydrogen is a transparent, non-toxic gas. It has no taste or odor and is not harmful. Using hydrogen as a fuel source in fuel cells produces no emissions, does not damage the atmosphere with carbon dioxide, and emits no nitrogen oxides.
How harmful is hydrogen use?
Although hydrogen is non-toxic, it can accumulate in enclosed spaces such as battery storage rooms and induce asphyxiation by displacing oxygen. This risk can be mitigated to some extent by adding odorants to hydrogen fuel, giving it a synthetic odor and warning people in the event of a leak.
What steps are being taken to avoid the creation of an explosive hydrogen-air mixture?
The facilities are built to be completely leak-proof. Flange connections are specifically developed for hydrogen, and the number of detachable connections is kept to a minimum. Furthermore, constant air exchange is assured in structures, and the facilities are outfitted with safety valves and pressure reliefs.
Is it correct that hydrogen could not be safely stored?
No, hydrogen can be stored, handled, and transported securely. For almost a century, the industrial gas business has done so.
What are the risks of a hydrogen gas leak?
Under contrast to gasoline and natural gas, hydrogen gas has high buoyancy in atmospheric conditions due to its low density; any escaping hydrogen gas ascends and disperses immediately, lowering the chance of an open-air ignition.
What is the process of electrolysis?
Water is split into its constituent’s hydrogen and oxygen by electrical current.
What types of electrolysis systems are there?
Electrolyzers are classified into three types: alkaline, proton exchange membrane (PEM) and solid oxide. Depending on the electrolyte material, these various electrolyzers operate in slightly different ways.
What exactly does ALK stand for?
The abbreviation for alkaline is ALK. Alkaline water electrolysers are characterized by slightly higher power consumption (compared to proton exchange membrane (PEM) electrolysis and electrolysis of water vapor), but the levels reached in terms of durability, reliability and security are excellent.
What are the distinctions between electrolysis systems?
The ion type that completes the electric circuit
Alkali: OH-
SOE: O2-.
How much energy is required to produce one kilogram of hydrogen using electrolysis?
To produce 1 kilogram of hydrogen, ammonia electrolysis in waste water requires only 1.55 kWh of electrical energy. 1 kg of hydrogen may provide 33 kWh of electrical energy when utilized in a fuel cell.
Which industries make extensive use of hydrogen?
• Renewable Energy Storage. Solar and wind power
• Power Generation
• Stationary Fuel Cells
• Power to Gas
• Methanation and many more...
What are the current industrial applications for hydrogen?
Hydrogen is largely employed as a component or catalyst in the manufacturing of ammonia, oil refining, and methanol, and these three processes currently account for the majority of hydrogen production.
How much hydrogen is needed to drive 100 kilometers in a medium-sized car?
1 kilogram of hydrogen will provide you 97-100 kilometers in any of the current fuel cell automobiles.
What amount of time does it require to refuel an energy unit electric vehicle?
Refilling an FCEV tank, like refueling a car, takes roughly three to five minutes.
What are the particular benefits of consolidating power from sustainable power sources and hydrogen?
Green hydrogen is completely sustainable because it emits no damaging gases during combustion or manufacture. Hydrogen is easily stored, allowing it to be used later for various purposes and at periods other than immediately after generation.
Is hydrogen merely a short-term solution?
No, hydrogen will be a significant and lasting component of a sustainable energy sector.
What are the primary components of the hydrogen generation energy mix?
Hydrogen can be created using a variety of domestic resources, such as fossil fuels, biomass, and water electrolysis with electricity.
What exactly are 'green,' 'grey/brown,' and 'blue' hydrogen?
The colors represent the profile of GHG emissions from the energy source or procedure used to extract hydrogen. Green has no emissions. Blue, even turquoise and pink has fewer emissions, whereas grey, brown, and black have higher emissions and a bleak future for global warming.

Sigma ALK Electrolyser

Producing enough hydrogen requires innovative solutions with our Sigma ALK electrolyser, an innovative ALK alkaline electrolysis system that uses wind and solar energy to produce hydrogen and is completely CO2-free. From initial planning to full operation with equipment on site, we can have you operational in as little as 4 months.

Advantages compared to PEM water electrolysis.

In comparison to polymer electrolyte water electrolysis, the advantages of alkaline water electrolysis are mainly:
  • Cheaper catalysts with respect to the platinum metal group-based catalysts used for PEM water electrolysis.
  • Higher durability due to an exchangeable electrolyte and lower dissolution of anodic catalyst.
  • Higher gas purity due to lower gas diffusivity in alkaline electrolytes.



Questions? The Sigma team is here for you. No matter in what country you are located, we are here to assist you. Please use the contact form below to contact us or alternatively call us at:



Rua Dr Justino Cruz 110

Braga, 3700-314







Sigma is the Global
Leader in Green Hydrogen Solutions

As an absolute believer in our green fully decarbonized future, our firm was founded with the principle of being the world's leading green hydrogen service provider. We believe from 2024 to 2050 a new world will emerge, and green hydrogen will be one of its foundational cores.


The fossil fuels era is soon to be extinct

The early adopters of green energy specifically green hydrogen will be positioned to become market leaders.


With possibilities beyond our wildest imagination, the world ahead is not an extension of the past. There will be massive changes as yesterday's solutions cannot solve the problems of tomorrow. In the next decades, every foundational sector of the economy will experience massive change, and energy and technology will see the biggest revolutions.

Sigma is where aspiration meets innovation we are dedicated to building and delivering green hydrogen solutions that not only create extreme value but also deliver lifelong sustainability.

We are heading towards a brand new prosperous, resilient, and equitable energy system. Sigma is your partner in this new journey that lies ahead.


Join our Newsletter

Subscribe to receive market and Sigma updates