We have envisioned to reach carbon neutrality to mitigate the consequences of climate change. This envisioned transition requires the substitution of fossil fuels for renewable energies. Nevertheless, we are a carbon-based society, where we use fossil fuels as the main source of carbon. Therefore, if we want to achieve the envisioned carbon neutrality on time, we need to substitute fossil carbon for renewable and neutral carbon (defossilized carbon). This thesis explores how this substitution is possible by looking into different aspects of defossilized carbon. From its sources such as CO2 direct capture and biomass to its use in the production of methane, methanol, and other promising chemicals.