Optimal Planning of Islanded Integrated Energy System With Solar-Biogas Energy Supply

Renewable-based integrated energy system (IES) is considered a viable energy supply alternative in many off-grid and remote regions of the world. However, high costs of islanded IESs with large-size batteries challenge further deployments of IESs. Considering the variable nature of renewable energy and distinctive characteristics of abundant biomass energy in remote regions, this article proposes a distributed solar-biogas residential IES, which can supply thermal, electrical and gas loads in remote locations, and utilize the complementarity nature of solar and biogas energy for reducing the dependency of IES on battery storage system. The proposed IES planning model, formulated as a two-stage MILP problem, is solved by the Benders Decomposition (BD) method to determine the optimal capacity of each component in IES planning. According to the proposed sensitivity analyses, load levels and feedstock prices have a substantial influence on investment decisions and total cost. The article also incorporates the thermodynamic effect of temperature on anaerobic digestions and illustrates the complementary economic and technical merits of solar and biogas energy in daily IES operations. Illustrative examples show the corresponding IES advantages on investment cost reduction and peak load shaving.