In the global effort to combat climate change, researchers worldwide are working tirelessly to discover innovative methods for extracting carbon dioxide (CO2) from the atmosphere and industrial emissions, to transform it into a valuable resource. This transformation of CO2 into a stable fuel capable of replacing fossil fuels in various applications has been a challenging endeavour, plagued by low carbon efficiency and the production of toxic, flammable, or difficult-to-handle fuels in previous attempts.
However, a groundbreaking development from scientists at MIT and Harvard University may revolutionize the field. They have devised an efficient process for converting CO2 into formate, a versatile substance with similarities to hydrogen and methanol. Formate can be utilized to power fuel cells and generate electricity. Notably, potassium and sodium formate, already manufactured at industrial scales and commonly used as de-icers for roads and sidewalks, possess several advantages. They are non-toxic, nonflammable, easy to store, and can remain stable in ordinary steel tanks for extended periods, ranging from months to even years.
This innovative technology holds the promise of scaling up to provide emissions-free heat and power for individual homes, as well as industrial or grid-scale applications. In traditional CO2-to-fuel conversion processes, a two-stage method was employed, initially converting the gas into calcium carbonate and then heating it to release carbon dioxide and convert it into a fuel feedstock, such as carbon monoxide. However, this second step was highly inefficient, typically achieving less than a 20% conversion rate. In contrast, the newly developed process achieves a remarkable conversion rate of over 90% by first converting CO2 into a liquid metal bicarbonate and then electrochemically transforming it into liquid potassium or sodium formate, utilizing low-carbon electricity sources like nuclear, wind, or solar power.
The resulting highly concentrated liquid formate solution can be efficiently dried, for example, through solar evaporation, to produce a stable solid powder suitable for long-term storage in standard steel tanks. This process offers a significant advantage over hydrogen storage, which experiences leakage at about 1% per day. Additionally, methanol, another alternative explored for CO2 conversion, is toxic and unsuitable for applications where leakage could pose health risks. In contrast, formate is considered benign and complies with national safety standards. The success of this groundbreaking technology hinges on several key optimizations, including membrane materials, pH control, and the prevention of unwanted side reactions. A buffer layer of bicarbonate-enriched fibreglass wool helps mitigate side reactions, ensuring the long-term efficiency of the system.
This development opens up a world of possibilities for diverse applications, ranging from household units to large-scale industrial or grid-based energy storage systems. Initial household implementations may involve a refrigerator-sized electrolyzer unit to capture and convert CO2 into formate, which can then be stored for later use, providing power and heat as needed.
In summary, this development represents a significant leap toward harnessing CO2 as a valuable resource, providing a viable path towards a more sustainable and environmentally friendly future.