The Different Colors of Hydrogen and Their Environmental Impacts

Hydrogen, the most abundant element in the universe, has recently gained attention as a potential source of clean energy. When considering the application of hydrogen for energy, it is essential to recognize that hydrogen can be produced through difference processes, each of which has a different environmental impact. Each of these processes is assigned a color—the primary ones are grey, blue, and green. Understanding these colors and their environmental implications is crucial for making informed decisions about the future of hydrogen as an energy source.

Grey Hydrogen

Grey hydrogen is the most widely produced form of hydrogen. It is primarily produced through a process called steam methane reforming (SMR), where natural gas reacts with steam to produce hydrogen and carbon dioxide (CO2). The carbon dioxide emitted during this process is generally released into the atmosphere, contributing to greenhouse gas emissions.

Environmental Impact: The production of grey hydrogen has a negative effect on the environment due to the release of CO2, a greenhouse gas.  These emissions from grey hydrogen are recognized contributors to climate change, exacerbating global warming and its associated impacts on weather patterns, sea levels, and ecosystems.

Blue Hydrogen

Blue hydrogen is similar to grey hydrogen in its production method, utilizing SMR. However, it employs carbon capture and storage (CCS) technology to prevent the CO2 from entering the atmosphere. The CO2 generated during hydrogen production is captured and then stored or utilized for other industrial purposes.

Environmental Impact: Blue hydrogen is considered a transitional solution on the path to a low-carbon future. While it reduces direct greenhouse gas emissions compared to grey hydrogen, the process of capturing and storing CO2 is not entirely flawless. There are concerns about potential leaks, safety issues, and the long-term stability of CO2 storage sites. Nevertheless, blue hydrogen represents progress towards a more sustainable hydrogen economy.

Green Hydrogen

Green hydrogen is often hailed as the cleanest form of hydrogen and is produced through a process called electrolysis. Electrolysis involves passing an electric current through water, separating it into hydrogen gas and oxygen gas. When renewable energy sources like solar, wind, or hydropower provide the electricity for this process, the hydrogen produced is considered green.

Environmental Impact: Green hydrogen production emits no greenhouse gases directly. Instead, the environmental impact depends on the source of the electricity used in the electrolysis process. If generated from renewable sources, green hydrogen is entirely emissions-free and has a minimal impact on the environment. However, if fossil fuels power the electricity grid, the carbon footprint of green hydrogen can increase, though still considerably less than grey hydrogen.

Effect on the Environment

The production of hydrogen from renewable sources may promote energy independence and reduce reliance on fossil fuels. It may also open the door to various applications, including clean transportation, energy storage, and industrial processes, without compromising the planet’s health.

Transitioning from grey to blue and, eventually, green hydrogen is essential to reducing greenhouse gas emissions and mitigating their adverse effects associated with climate change.

Challenges to the Adoption of Hydrogen

Despite the promise of hydrogen, cleaner transportation based on this abundant element faces significant obstacles. One challenge facing hydrogen fuel cell vehicles is the current, relative high cost of hydrogen. Comparing California gasoline and hydrogen retail prices from 2021, the cost of driving was:

  • Hybrid vehicle: 9.3¢ per mile
  • Gasoline vehicle: 13.7¢ per mile
  • Hydrogen fuel cell: 27.6¢ per mile

To be competitive with hybrid gasoline vehicles on a per-mile basis in 2021, hydrogen needed to be two-thirds cheaper. It’s important to note that California’s retail hydrogen prices are already artificially low because of subsidies from the California Energy Commission.

Until more research is done in hydrogen compression and delivery, which make up 80 percent of the cost of hydrogen, it is unlikely that its price will fall. Significantly, there is lack of research or pending breakthroughs in these two vital areas, so there isn’t much chance that hydrogen will be a competitive fuel source for the foreseeable future.

For over 35 years, the BAI Group has provided technical consulting services to private and public entities involved with environmental development projects. The services we traditionally provide our clients include studies, designs, permit applications, construction management/CQA along with other compliance monitoring and reporting activities. Contact us today to discuss a cost-effective approach to your renewable energy system needs.