Hydrogen has recently gained significant attention, yet it is essential to distinguish between viable applications and mere speculation. As the most abundant element in the universe, hydrogen constitutes two-thirds of water's atomic structure and is found in many organic compounds. While hydrogen was first artificially produced in 1671 and recognized as an element in 1766, its relevance has surged only in the past few years.

The current excitement centers around "green hydrogen," which is generated through electrolysis using renewable energy sources. Although this method has existed for over two centuries, it accounts for less than 0.1% of global hydrogen production, with the majority derived from fossil fuels. Currently, hydrogen serves primarily in industrial applications like oil refining and steel production, but there are plans to broaden its usage to sectors like transportation and electricity generation.

I find new technologies exhilarating, but I have mixed feelings about hydrogen. While it may contribute to reducing emissions in hard-to-abate sectors such as steel manufacturing and aviation, the proposed applications often seem questionable.

A prominent vision for hydrogen's future is its role in balancing the intermittent nature of renewable energy sources like wind and solar. The theory suggests that during periods of excess energy production, hydrogen facilities can utilize surplus electricity to create hydrogen for later use.

Another key area where hydrogen is being promoted is in passenger vehicles, with numerous countries establishing incentives for this application. Advocates often highlight benefits such as longer driving ranges and quicker refueling times compared to battery-electric vehicles.

As a mechanical engineer with expertise in renewable energy technologies, I have identified four significant concerns regarding the broader application of hydrogen.

First, developers of wind farms typically do not construct projects expecting to generate electricity at consistently low or negative prices. Investment in renewable energy must be economically viable, and businesses will avoid scenarios that threaten profitability.

Second, for hydrogen to be a feasible storage option or a viable fuel for cars, its production costs must decrease dramatically—by about two-thirds—to compete with fossil-fuel-derived hydrogen and other electricity sources. Additionally, the production process needs to become more efficient, which is challenging given the infrequent instances of negative electricity prices.

The third issue is efficiency. Directly sending green electricity to the grid is far more efficient than converting it to hydrogen, which incurs losses at each stage—from electrolysis to storage and back to electricity generation. The overall round-trip efficiency for hydrogen storage is about 35%, requiring nearly three times more electricity to achieve the same result as direct grid usage.

Given that few countries have achieved a zero-emissions electricity grid, using hydrogen can inadvertently increase emissions, particularly when alternatives like batteries exist.

The fourth concern is that hydrogen technology development may lag behind other energy storage advancements. Current discussions often fail to consider the rapid progress of competing technologies, which will continue to evolve.

Hydrogen bears similarities to fossil fuels, being transportable via gas pipelines and usable for heating and power generation. This resemblance makes it appealing to fossil fuel companies and governments in resource-rich nations, creating a potential rationale for expanding fossil fuel capacity under the guise of renewable energy policy.

However, hydrogen is only considered "green" when produced from renewable sources. Some countries have set targets for green hydrogen without committing to renewable electricity goals, raising concerns about the risk of continuing to rely on fossil fuels.

Until electricity grids achieve complete cleanliness, using hydrogen in applications that could otherwise be electrified is counterproductive. Renewable energy should be routed directly to the grid or stored using more efficient methods like batteries or pumped hydro systems. Only when a surplus of renewable energy becomes available should hydrogen be utilized for storage or electricity generation.

Despite my critiques, I believe there are valuable opportunities for hydrogen to contribute to a sustainable energy future, especially in specific contexts where its advantages are pronounced.

In some cases, such as remote locations with abundant renewable resources but limited grid access, hydrogen may offer a promising solution. Using wind turbines to produce hydrogen directly can also mitigate some inefficiencies associated with traditional electricity generation.

Additionally, hydrogen could serve as a long-term storage option in regions with seasonal energy demand fluctuations. It may also prove beneficial in hard-to-electrify industries like steel and cement production or aviation, where current battery technology falls short.

I remain cautiously optimistic about green hydrogen's role in the energy transition, yet it is crucial not to view it as a catch-all solution to climate challenges. Careful targeting of hydrogen applications is necessary to realize its potential benefits while avoiding unintended consequences.

Identifying and prioritizing the most promising use cases for hydrogen is vital, especially given the current low levels of green hydrogen production. As capacity expands, it should be directed toward applications where electrification is not feasible.

This article marks the beginning of my exploration into hydrogen applications. In the coming months, I will engage with experts in hydrogen projects and policies. Follow my YouTube channel for insights and discussions as I delve deeper into the realities versus the hype surrounding hydrogen. If you are involved in a hydrogen initiative, I would love to hear from you!