Study on the electrochemical production of hydrogen from bio methanol and renewable energy

One of the most important challenges of the twenty first century is the reduction of greenhouse gas emissions, which are the main cause of climate change. The use of renewable energy sources, such as wind, solar and hydroelectric power, stands as an alternative to the use of fossil fuels that are still widely used to meet the growing demand for energy. The need to meet climate requirements arises in a context in which fossil fuels cannot be completely eliminated yet: firstly, they are widely used today as fuels for the transport sector; on the other hand, the need to constantly feed the electrical grid requires a stable energy source that can cope with the randomness of renewable energy. Among the possible climate-neutral alternatives there is hydrogen: it is an energy carrier that can be used both to produce electricity and as a fuel for the transport sector. Nowadays Hydrogen is mainly produced from fossil fuels such as coal and methane, only less than 1% is produced by electrolysis of water. The latter relies on a type of device, called an electrolyser, that uses electricity to break up the water molecule, producing hydrogen. The major problem of this technology is that it is highly energy intensive. An alternative proposed within this study is aqueous methanol electrolysis. The studies carried out on this topic show that the theoretical operating voltage of methanol electrolysis is 0.02 V compared to the 1.23 V of water electrolysis, so for the same amount of hydrogen produced, the energy consumption is about 60% lower for methanol electrolysis rather for water electrolysis. Since information in the literature is scarce and often conflicting, this study has the aims to investigate the performance of a PEM-type electrolyser in terms of polarisation curves, trying to find the optimal configuration by varying the operating temperatures and the concentration of methanol in the solution. Finally, the polarisation curve that presents the lowest voltage for the same current density is used to develop a case study where it is supposed to power the cars and buses on the island of San Pietro with the hydrogen produced by the aqueous methanol electrolyser, concluding the analysis by calculating the Levelized Cost Of Hydrogen. The first four chapters illustrate the energy supply problem and how hydrogen and methanol can help in the decarbonization process. Chapter five describes the test bench and the methodology used for the results shown in chapters 6 and 7. Finally, the eighth chapter is dedicated to the description of the case study.