Green Hydrogen Energy

Hydrogen fuel is often seen to be a clean fuel. However, a closer look into its current production methods uncovers some dirty truths. There are two main aspects to take into account when considering how sustainable hydrogen is as an energy source - the production of hydrogen and the usage of hydrogen. It is undeniable that the usage of hydrogen is clean since the only byproduct when hydrogen is consumed in a fuel cell is water. However, the different production methods (notably methods involving coal or gas) are less clean and often involve various sources of carbon emissions.

Hydrogen Color Spectrum

Despite being a colorless gas, within the energy industry, hydrogen is classified into different colors - often called the “hydrogen rainbow.” The colors are assigned based on the method of production and currently are blue, brown/black, green, gray, turquoise, pink, purple, red, and white. The most common ones are gray, blue, and green.

• Gray hydrogen makes up the majority of the hydrogen produced currently and is created by reforming natural gas (i.e. steam-methane reforming). These processes release about 9.3 kilograms of carbon dioxide per kilogram of hydrogen produced, making it unsustainable.

• Blue hydrogen is produced in the same manner as gray hydrogen except that additional techniques are added to ensure that the carbon dioxide produced isn’t released. This is done through a technology called Carbon Capture and Storage (CCS) which is when the carbon is captured at the production site and stored.

• Green hydrogen is produced through electrolysis - a process in which water is split into hydrogen and oxygen molecules through electricity (sourced via renewable energy such as wind and solar power). This process only emits water vapor and thus is the cleanest form of hydrogen thus far. However it only makes up about 0.1% of global hydrogen production.

In the range of colors, green hydrogen is the most sustainable and thus switching to this would be a step forward in reducing emissions.

Is Green Hydrogen a Viable Source?

Green hydrogen is viable for multiple reasons. First, green hydrogen is practically limitless since only water and electricity is needed to create it. This also makes it extremely versatile as it can be used directly when produced or transported to another location. Green hydrogen has many applications. The most notable field is the transportation sector (aviation, land transport, and automobiles). By 2050, it is estimated that green hydrogen has the potential to supply up to 25% of the world’s energy needs.

Although green hydrogen is conceptually viable, there are many factors that prohibit feasibility. The most notable one is cost. On top of the cost to develop this technology, the underlying cost of the renewable electricity used in electrolysis is a major contributor and creates price fluctuations. In comparison to its blue and gray counterparts, whose costs are dependent on cheaper coal and natural gas, green hydrogen energy has a long path to go before it can replace them.

Current Developments in the Green Hydrogen Sector

Since green hydrogen is not entirely viable due to cost and efficiency issues, there are numerous research projects ongoing. Some projects target improving electrolysis to make it more efficient and cost-effective through various methods such as non-noble metals electrocatalysts, photoelectrolysis, and thinner organic membranes.

In terms of hydrogen usage, there have been investigations into using it as a replacement for electrochemical batteries since electrochemical batteries have a range of issues spanning from limited capacities, high costs, and low power densities. Hydrogen can manage the unpredictability of the production that renewables suffer. It is able to store the electricity as hydrogen that is readily converted back into electricity by a fuel cell.

Evidently, green hydrogen energy is promising as many countries have been funding green hydrogen research. The Biden-Harris administration’s Infrastructure Investment and Jobs Act has committed $9.5 billion to develop clean hydrogen hubs and develop electrolysis processes which can be a central driver for greater innovation and adoption. The European Commission has approved $5.2 billion in funding for green hydrogen projects.

With the technological advances, lower cost of electrolyzers, and improvements in efficiency, the commercial viability of green hydrogen production has greatly increased. In fact, it is predicted that in 2050, green hydrogen can be cheaper than natural gas with a projected cost of between $0.70 to $1.60/kg.

Policy Actions Needed for a Hydrogen Future

The term hydrogen economy has been an ongoing discussion amongst policymakers and developers. This idea refers to using hydrogen fuel in order to decarbonize commercial fuels thus creating an environmentally-greener economy. In order to reach this point, there are three main actions that need to be taken. First, governments should invest and prioritize building green hydrogen infrastructure for producing, transporting, and storing green hydrogen. Second, governments should increase investments in research and development of green hydrogen technology and fund innovations - including both foundational technology as well as the commercialization of green hydrogen. Third, policymakers should take into account green hydrogen benefits beyond carbon abatement like reduction of other pollutants like sulfur and particulates and improvements to grid resilience.

In conclusion, green hydrogen has the potential to make a meaningful impact on the environment - it just needs proper policy actions to help reach it.

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Chloe Ng is a freshman studying Chemical and Biomolecular Engineering and Earth Science at the University of Pennsylvania.