The algae-producing airborne cities can be 100% emission-free and are capable of generating hydrogen gas without consuming land needed for crops or forests, no how about utopia, huh?

Yeah, you probably think this is only a pretty neat concept, that will never get built, but times are changing friend, and what you consider impossible today, may be accomplished tomorrow easily. So never say never to new ideas, aight?

According to the architects, “the output obtained by a farm with micro-seaweed would be superior to those made currently with farming means to produce biodiesel or bioethanol. This could be estimated at 1000 litres of hydrogen for 330 grams of chlorophyll per day whereas for example colza produces roughly only 1000 litres of oil per hectare . . . a hectare of seaweed could thus produce organically 120 times more biofuels than a hectare of colza, soya or sunflower.”