MIT engineers develop a scalable, low-emission method using recycled aluminium, seawater, and a gallium-indium alloy to produce green hydrogen at $9 per kilogram, offering a promising alternative for transport and maritime fuel with reduced environmental impact.
Recent advancements by a team of engineers at the Massachusetts Institute of Technology have positioned hydrogen as a more viable candidate for sustainable fuel, a potential breakthrough in addressing climate change. Traditionally, hydrogen production relies heavily on fossil fuels, undermining its green credentials. The innovative method from MIT leverages recycled soda cans, seawater, and a gallium-indium alloy to generate hydrogen in a process that boasts a dramatically lower carbon footprint.
The researchers conducted a comprehensive life cycle assessment to quantify the environmental impact associated with their hydrogen production method. They determined that the process emits approximately 1.45 kilograms of carbon dioxide for every kilogram of hydrogen produced. In stark contrast, conventional fossil fuel-based methods emit up to 11 kilograms of CO₂ for the same amount of hydrogen, revealing the significant advantages of this new approach.
Lead author Aly Kombargi, who completed his PhD in mechanical engineering at MIT, highlighted that their process brings them “in the ballpark of green hydrogen.” He emphasised how this method not only showcases the potential of aluminium as a clean energy source but also sets the stage for scalable hydrogen deployment in transportation and energy systems in remote areas.
At the heart of their innovative method is the treatment of aluminium to expose its reactive form. Typically, aluminium reacts poorly with water due to an oxide layer that forms upon exposure to air. By treating aluminium with a gallium-indium alloy, the researchers were able to bypass this barrier, allowing for an efficient reaction with seawater that produces hydrogen. Notably, the salt in seawater assists in recovering the gallium-indium alloy, making the process more cost-effective.
The significance of using recycled aluminium as a starting point cannot be understated. By sourcing aluminium from used soda cans rather than mining new ore, the researchers significantly reduce the carbon emissions associated with aluminum production. This factor alone makes their process not only greener but also economically appealing, as they calculated the cost of their hydrogen fuel to be approximately $9 per kilogram—competitive with other green hydrogen technologies powered by solar and wind energy.
Beyond its application for cars, this technique holds immense potential for maritime usage. In recent discussions, Kombargi mentioned the development of compact reactors designed to generate hydrogen on board marine vessels, promoting an efficient means to power ship engines and potentially reduce fuel transportation logistics altogether.
The study also identified an intriguing byproduct of their process, known as boehmite, which is utilised in the fabrication of semiconductors and other industrial products. If recovered, this byproduct could offset some production costs, enhancing the economic viability of this hydrogen production method.
As they refine their approach, the team envisions a future where hydrogen production is both efficient and accessible, involving a straightforward process: scrap aluminium would be transformed into fuel pellets on-site at recycling facilities, transported to fuel stations, and finally combined with seawater to generate hydrogen on demand. This flexibility ensures not only safety but also a streamlined supply chain, potentially overcoming many of the logistical hurdles currently associated with hydrogen fuel.
