Cogeneration of power and substitute of natural gas using biomass and electrolytic hydrogen

Storing renewable energy sources is becoming a very important issue to allow a further reduction of greenhouse gas emissions. Most of such energy sources generate electric power which not always can be conveniently transferred to the grid and also its conversion to hydrogen presents some critical aspects connected mainly to hydrogen distribution and storage. Electrolysis generates not only hydrogen, but also oxygen which could be used to burn biomass or waste products (oxycombustion) in power plants with the result to obtain an exhaust gas containing mainly water and CO2. This last can be converted into a mixture of methane and hydrogen by reacting with electrolytic hydrogen, so that the power used for electrolysis is stored into a fuel which can be distributed and stored just like natural gas. In this paper, an innovative biomass fuelled plant has been designed and simulated for different layouts with an internal combustion engine as a main power system. Utilizing hydrogen and oxygen produced through electrolysis and applying a hydrogasification process, the plant produces electricity and a substitute of natural gas. The result of such simulations is that the electricity can be stored in a useful and versatile fuel with a marginal efficiency up to 60%.