Researchers at Penn State University have made a groundbreaking discovery in the pursuit of clean energy alternatives: coal could hold the key to storing hydrogen gas, similar to how batteries store energy. This innovative approach addresses a crucial challenge in establishing a sustainable energy supply chain, potentially reducing our reliance on fossil fuels. [1]

“We found that coal can be this geological hydrogen battery,” said Shimin Liu, associate professor of energy and mineral engineering at Penn State. “You could inject and store the hydrogen energy and have it there when you need to use it.” [1]

Figure 1. Coal

Figure 1 shows coal. According to scientists, hydrogen is a clean-burning fuel that offers great potential for powering energy-intensive sectors such as transportation, electricity generation, and manufacturing. However, significant efforts are still required to develop a robust hydrogen infrastructure and ensure its affordability and reliability as an energy source. The road ahead involves overcoming various challenges to fully harness the benefits of hydrogen in driving a sustainable and efficient energy economy. [1]

One crucial aspect to address in harnessing the potential of hydrogen is the development of efficient and cost-effective storage methods. Scientists have highlighted the intriguing potential of geologic formations in this regard. These formations can store substantial quantities of hydrogen, enabling the accommodation of fluctuating energy demands that vary on a daily or seasonal basis. [1]

“Coal is well-studied, and we have been commercially producing gas from coal for almost a half century,” Liu said. “We understand it. We have the infrastructure. I think coal would be the logical place to do geological hydrogen storage.” [1]

To examine the feasibility of this concept, the researchers conducted a comprehensive analysis of eight coal varieties sourced from different coalfields across the United States. The objective was to gain deeper insights into the sorption and diffusion capabilities of these coals, specifically determining their capacity for storing hydrogen. By studying these properties, the scientists aimed to assess the potential of coal as a viable medium for hydrogen storage. [1]

In their study published in Applied Energy, the scientists reported that all eight coal samples demonstrated significant sorption properties. Among them, the low-volatile bituminous coal from eastern Virginia and anthracite coal from eastern Pennsylvania showcased the most promising results during testing. [1]

“I think it’s highly possible that coal could be the very top selection for geological storage from a scientific perspective,” said Liu. “We find that coal outperforms other formations because it can hold more, it has existing infrastructure and is widely available across the country and near populated areas.” [1]

Depleted coalbed methane reservoirs are identified as promising candidates for storing hydrogen. These reservoirs, which have been utilized as a significant source of conventional fossil fuel energy, contain unconventional natural gas like methane. In a process known as adsorption, methane adheres to the surface of the coal. Similarly, injecting hydrogen into coal would result in its absorption or adherence to the coal. Typically, these formations are characterized by an upper layer of shale or mudstone, which acts as a seal, effectively retaining the methane or hydrogen until it is required and can be extracted as needed. The scientists propose leveraging this natural storage mechanism for hydrogen within depleted coalbed methane reservoirs. [1]

“A lot of people define coal as a rock, but it’s really a polymer,” Liu said. “It has high carbon content with a lot of small pores that can store much more gas. So coal is like a sponge that can hold many more hydrogen molecules compared to other non-carbon materials.” [1]

The scientists designed special equipment to conduct the experiments. Coal has a weaker affinity with hydrogen compared to other sorbing gases like methane and carbon dioxide, so traditional pressurized equipment for determining sorption would not have worked. [1]

“We did a very novel and very challenging design,” Liu said. “It took years to figure out how to do this properly. We had to properly design an experiment system, trial and error based on our previous experience with coals and shales.” [1]

The research findings indicated that anthracite and semi-anthracite coals exhibit favorable characteristics for hydrogen storage in depleted coal seams. On the other hand, low-volatile bituminous coal was identified as a better candidate for gassy coal seams. These findings suggest that developing hydrogen storage within coal mining communities holds significant potential. It could not only bring new economic opportunities to these regions but also contribute to the establishment of a comprehensive hydrogen infrastructure across the nation. This dual benefit would foster both regional development and the advancement of clean energy technologies on a broader scale. [1]

“In the energy transition, it’s really coal communities that have been the most impacted economically,” Liu said. “This is certainly an opportunity to repurpose the coal region. They already have the expertise — the energy engineer and skills. If we can build an infrastructure and change their economic opportunities — I think that’s something we should consider.” [1]

Source: Penn State

References:

1. https://www.psu.edu/news/earth-and-mineral-sciences/story/hydrogen-battery-storing-hydrogen-coal-may-help-power-clean-energy/

Cite this article:

Hana M (2023), Unleashing Hydrogen Power from Coal for a Clean Energy Revolution, AnaTechmaz, pp.445