Assessing the sustainable abilities of a pilot hybrid solar-pyrolysis energy system using emergy synthesis

With the increasingly serious global climate and energy problems, hybrid renewable energy systems have been widely developed. Sustainability of a pilot hybrid solar-pyrolysis energy system (HSPES) was evaluated using emergy analysis. The total emergy input of the system was 6.90E+15 sej/yr, and it was greatly dependent on the renewable resources from external environment. Suitable emergy indices such as unit emergy value, renewability, emergy yield ratio, environmental load rate, and emergy sustainability index, were introduced and analyzed in detail, with values of 7.45E+04 sej/J, 63.51%, 1.00, 0.57, and 1.74, respectively. The results showed that the system was more dependent on renewable resources, had less impact on the environment, and had relatively good sustainability, but the utilization of local resources was quite low. However, this system was relatively weak in the exploitation and utilization of local resources. On the basis of life cycle assessment and emergy analysis, the Pollutant Degradation Emergy (PDE) result of the system was 2.77E+14 sej/yr. There was no significant difference between the emergy indices results based on PDE and its original value, the pollutants emissions of the system did not show a significant impact on the results of selected emergy indices, and the impact of system pollutants on the environment was relatively weak.