into biomass and they breathe out oxygen, so oxygen is actually our only by—product of this product. which is not a bad by—product, really. the health authorities don't seem to mind! spencer laughs. so, right here in geothermal iceland, where electricity and hot water are both essentially clean, green and on tap, growing this algae ends up being carbon negative — it pulls more co2 out of the environment than the electricity puts back in. but in order to feed the world, these algae farms would need to be placed around the globe, and not everywhere�*s on top of a volcano. the system itself is always carbon negative because we take in c02, we fix it in biomass and we breathe out oxygen. but if you're having to use electricity that's generated through coal... exactly. ..then the system is generating co2 as well... yes, yes. ..and can then you connect the pipe from the power station