Today humanity faces a challenge: Global warming that is caused by emissions of CO2. To reduce CO2 emissions, usage of CO2 as a renewable carbon source has gained attention. In particular, the CO2-based synthesis of formic acid has been intensively studied, since in addition to utilizing CO2, formic acid could also act as chemical storage of fluctuating renewable energy. Developing such storage is paramount for any renewable energy system due to the fluctuating occurrence of e.g. wind. However, for the CO2-based formic acid synthesis, only a few processes have been developed. Thus, novel formic acid synthesis processes are developed in this thesis. The development considers process structure and solvents, as well as formic acid derivatives due to the unfavorable equilibrium of the CO2-based formic acid synthesis.