This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.
As countries around the world increasingly tap into renewable energy, scientists are exploring the best ways to manage excess energy efficiently for all times of the day and night—including at times of peak usage, on cloudy days, or when the wind isn’t blowing. In a recent study, a group of Turkish researchers have computed models suggesting that hydrogen storage can store renewable energy at large scales and relatively low costs.
For example, their model suggests that if Germany expanded its use of hydrogen storage at renewable energy plants nationwide, this would result in roughly 60 percent lower costs than the nation’s current energy systems. The results were published earlier this year in IEEE Transactions on Engineering Management.
“We strongly believe the green hydrogen can be a game changer once optimal scales are achieved.” —Denizhan Guven, Istanbul Technical University
Renewable energy sources like wind and solar are key to a sustainable future, yet supply from these sources can fluctuate depending on environmental conditions. As a result, there’s a need to be able to efficiently store any excess energy while production is high, which could be used later on when wind or solar conditions are less favorable and production is low.
One viable option is through hydrogen storage, which involves compressing the element into tanks, cooling it to form a liquid, binding it with metals, storing it in chemical compounds, or adsorbing it onto materials like activated carbon.
“Each method has its pros and cons, with factors like safety, efficiency, and practicality influencing their use in various applications,” explains, Zeynep Bektas, an assistant professor at Kadir Has University, in Türkiye.
Bektas and her colleagues were interested in exploring how well various forms of energy storage compare to one another at large scales. They had a panel of experts score six different energy-storage methods—including hydrogen storage, compressed air, and four different battery types (lithium ion, sodium sulfur, vanadium redox, and lead acid)—finding hydrogen storage to be the most suitable for grid-scale operations.
How well does hydrogen store renewable energy?
The researchers then created models to evaluate the impact of integrating hydrogen storage at large scales. For the first case study, they used data from one of the first power plants designed to combine renewable energy and on-site hydrogen storage, established in Germany by one of the country’s renewable energy producers, Enertrag, in 2011. The researchers’ simulations revealed that scaling up hydrogen tech across Germany could cut the nation’s energy costs by nearly two-thirds.
Bektas and her colleagues also modeled hydrogen storage in the Netherlands using data from one the nation’s energy network operators, Gasunie, whose network includes renewable energy, natural gas, and hydrogen storage. Bektas’s group’s model suggested that hydrogen storage would lead to an estimated 58 percent reduction in energy costs for the country.
Denizhan Guven, a research assistant at Istanbul Technical University, one of the study’s coauthors, says the environmental impact of hydrogen usage is notable, too. Total life-cycle emissions of green hydrogen, he says, represent about 1 kilogram of carbon dioxide per kilogram of H2, while one kilogram of petroleum yields some 10.16 kg of CO2.
“These numbers demonstrate a substantial difference in carbon emissions between green hydrogen and petrol, with green hydrogen being significantly cleaner,” he says, adding, “We strongly believe the green hydrogen can be a game changer once optimal scales are achieved.”
On the other hand, the researchers note, hydrogen is of course highly flammable and must be stored under high pressure conditions. These limitations make it challenging and costly today to safely manage and store hydrogen.
However, Bektas says the price of hydrogen storage will go down as it is more widely adopted on large scales, and this is where the cost-savings identified in the study would come from. Notably, what they are proposing is a renewable energy system integrated with hydrogen storage, rather than a system that relies solely on hydrogen.
“Because green hydrogen is clean…versatile, and compatible with energy transition, it is one of the most promising energy-storage technologies for the coming decades,” she says.
