The Colors of Hydrogen, Explained
As a factor in mitigating climate change, renewable energy is critical to reducing greenhouse gas emissions that contribute to global warming. Hydrogen is a renewable energy source that emits zero carbon emissions — only water vapor, electricity, and heat. Although it has many colorful descriptions, hydrogen itself is a colorless gas. The “color” assigned to hydrogen indicates how it was produced.
The energy industry uses the colors of hydrogen to differentiate between them easily. However, there is no official naming convention for hydrogen, so these terms might change between regions and as hydrogen production evolves.
So what exactly is the meaning behind each color of hydrogen? Today we’ll talk about the eight colors of hydrogen: their production methods, use cases, and our predictions for the future of hydrogen energy.
Table of Contents
- Blue hydrogen
- Black/Brown hydrogen
- Green hydrogen
- Pink hydrogen
- Gray hydrogen
- Turquoise hydrogen
- Yellow hydrogen
- White hydrogen
- The future of hydrogen energy
Blue hydrogen is made in a process known as steam methane reformation (SMR), in which natural gas is mixed with hot steam and a catalyst.
The result is hydrogen, with carbon dioxide as a byproduct. Therefore, carbon capture and storage (CCS) is a crucial part of the production of blue hydrogen. Once the emissions are captured and stored underground, the process can be considered carbon-neutral.
Blue hydrogen could release methane emissions during drilling, extraction, and transportation, even with proper carbon capture and storage. Although methane has a shorter atmospheric lifetime than carbon dioxide, just one ton of methane has the same impact as 28 to 36 tons of carbon dioxide after 100 years.
Black or Brown Hydrogen
Although a clean-burning fuel, some forms of hydrogen generate carbon emissions during production. Black and brown hydrogen are often used interchangeably to refer to any hydrogen produced from fossil fuels through gasification. However, brown hydrogen specifically comes from coal gasification.
Because the carbon emissions generated during gasification are not recaptured, brown hydrogen is the most environmentally damaging form of hydrogen production. Essentially, brown hydrogen releases as much carbon dioxide into the atmosphere as burning coal does.
Green hydrogen is a true zero-emissions energy source, often called the future of clean energy. Although many other forms of hydrogen emit greenhouse gases somewhere in the production process, green hydrogen does not.
To be considered 100 percent clean energy, green hydrogen must be produced using electricity from renewable sources, such as hydro, solar, or wind power.
In a process known as electrolysis, water molecules are split into hydrogen and oxygen. The hydrogen is extracted as fuel, and the oxygen is then vented into the atmosphere with no negative environmental impact.
The result is a completely clean form of hydrogen made from renewable energy sources without carbon emissions.
Similar to green hydrogen, pink hydrogen is generated through electrolysis. But rather than renewable energy sources like solar or wind power, this process is powered by nuclear energy.
Other forms of pink hydrogen include red hydrogen, which uses nuclear power to power the high-temperature catalytic splitting of water. Purple hydrogen combines nuclear power and heat to perform a process called thermochemical electrolysis.
Even though all hydrogen burns “cleanly,” not all hydrogen production is equal. The most common form of hydrogen production is gray hydrogen, extracted from natural gas without recapturing the greenhouse gases released during the process. Today, almost all hydrogen produced for industrial use is gray.
One of the newer forms of hydrogen production, turquoise hydrogen uses methane pyrolysis to produce hydrogen and solid carbon rather than gaseous emissions. This eliminates the need for carbon capture and storage. In addition, the resulting carbon can be used in other applications, like manufacturing tires or improving soil.
Yellow hydrogen is an emerging form of hydrogen production through solar power electrolysis. However, sometimes yellow hydrogen means hydrogen generated through electrolysis using mixed energy sources.
White hydrogen refers to geological hydrogen found in naturally occurring underground deposits created by fracking. However, there are currently no means to extract this hydrogen.
The Future of Hydrogen Energy
Overall, hydrogen is a key component of global efforts to address the pressing challenge of climate change.
By transitioning from fossil fuels to hydrogen, we can significantly reduce our carbon footprint and slow the pace of climate change. In addition to reducing emissions, hydrogen will create jobs, improve energy security, and promote sustainable development.
However, there is one form of hydrogen that has the potential to be a game-changer in the transition to a low-carbon economy: green hydrogen. It can be used as a clean fuel for transportation, heating, and industrial processes and can help decarbonize sectors that are difficult to electrify.
The cost of producing green hydrogen is currently higher than other hydrogen colors, but experts predict this will change as the technology improves and economies of scale are achieved. Governments worldwide are investing heavily in green hydrogen infrastructure, research, and development, which is expected to drive down costs further.
With its versatility and potential to reduce greenhouse gas emissions, green hydrogen has a promising future as a vital component of a sustainable energy system.
Partner With FASTECH For Hydrogen Infrastructure Projects
Hydrogen plays a vital role in the transition to renewable energy. By switching from fossil fuels to hydrogen, industries can drastically reduce their carbon emissions and mitigate the effects of climate change. In addition, learning the colors of hydrogen is a helpful tool for differentiating the various hydrogen production methods.
As a leading provider of hydrogen fueling infrastructure solutions, FASTECH has built over 30 hydrogen stations for leading corporations and energy providers like Shell and Chevron. Our end-to-end EPC services include design, engineering, construction, maintenance, testing, and compliance for each project.
Contact us today if you’re looking for a trusted partner for your upcoming energy infrastructure project.