Power-to-food: energy use, costs, and applications across industrial CO₂-to-food pathways

Food production from CO₂ goes beyond photosynthetic organisms, it includes nonbiological synthesis of fats or carbohydrates, and fermentation-derived microbial foods. Their potential for reducing CO₂ emissions, land use, and water use could palliate the impacts of industrial agriculture—climate change, land degradation, water scarcity, deforestation, etc. Their ability to produce food in extreme environments also sparked interest for space missions, food security, and civilizational resilience.

However, their high energy consumption presents an unsolved challenge, requiring consistently cheap, low-CO₂ energy to realize gains though displacing unsustainable agricultural products. We compare the current and future potential energy use of twelve CO₂ food pathways, finding that power-to-food efficiencies vary by orders of magnitude. Synthetic fats and hydrogen-oxidizing bacteria (HOB) show the best results (10%+), with HOB offering superior nutritional value—an appealing fit for deep space and other environments with resupply challenges.

HOB and synthetic fats are best placed for economic competition with agricultural products like butter, egg powder, whey protein, or plant protein isolates (~$4-7/kg dry). Acetate-mediated production cost might beat microalgae photobioreactors, perhaps even open-pond microalgae and vertically-farmed lettuce, but not cheaper staple crops farmed outdoors. Synthetic carbohydrates are unlikely to be competitive.