Sewage sludge gasification as an alternative energy storage model

Renewable energy production, storage and utilization has been studied in connection with fluctuating renewable power production and demand. The coupling has been considered of surplus renewable power with sewage sludge gasification and renewable syngas storage. High quality syngas produced with power support can be introduced into a gas distribution network or stored and utilized on site. Both systems enable gas consumption at power and heat demand periods. The efficiency of power conversion to syngas produced from high moisture sewage sludge has been studied using a developed equilibrium thermodynamic model for the gasification process providing the calculated prediction of the syngas amount and composition. Furthermore, the total energy efficiency has been studied of the syngas production and utilization system. The results show that the optimum scenario to get syngas suitable to introduce into a natural gas distribution network would be to gasify sewage sludge with 35-40 wt.% moisture, while the optimal parameter for syngas to be valorized onsite is, in terms of efficiency, with SS dried to 20 wt.% of moisture content. In the first scenario, a little more power is produced from stored gas in a natural gas distribution network than consumed, and almost twice as much is produced with on-site production, storage and utilization. The study has showed a technically feasible management option for energy production, storage and consumption with available technologies and infrastructure.