Renewable CO2 recycling and synthetic fuel production in a marine environment.

A massive reduction in CO2 emissions from fossil fuel burning is required to limit the extent of global warming. However, carbon-based liquid fuels will in the foreseeable future continue to be important energy storage media. We propose a combination of largely existing technologies to use solar energy to recycle atmospheric CO2 into a liquid fuel. Our concept is clusters of marine-based floating islands, on which photovoltaic cells convert sunlight into electrical energy to produce H2 and to extract CO2 from seawater, where it is in equilibrium with the atmosphere. These gases are then reacted to form the energy carrier methanol, which is conveniently shipped to the end consumer. The present work initiates the development of this concept and highlights relevant questions in physics, chemistry, and mechanics.