Multiobjective Optimisation of Grid Connected Wind-PV-Micro Hydro-Battery Systems: Case of a Dairy Farm in North of Scotland

Hybrid Renewable Energy Systems (HRES) have the potential to provide economical, reliable, and environmentally friendly energy for agriculture and dairy industries, hence playing a key role in achieving net-zero targets in that sector. This paper presents the results of hybrid system design optimisation conducted for a dairy farm in Oban, Scotland. Micro-hydro (MH), PV, wind, battery bank and grid are considered as potential components of the hybrid system. The optimum configuration and size of the hybrid systems are obtained via solving a multiobjective optimisation problem with total lifespan cost (TLSC) and grid dependency as two objectives to be minimised, and discounted profit to investment ratio (DPIR), renewable production and power feed to the grid as three objectives to be maximised. The nondominated solutions contain three different configurations, namely, MH-Grid, MH-Battery-Grid, and PV-MH-Battery-Grid. The nondominated solutions are evaluated and compared against 13 system performance measures, namely, net present value (NPV), initial cost, TLSC, cost of electricity from grid, income from grid, net income from grid, DPIR, grid dependency (%time), grid dependency (%energy), CO2 emission offset, total annual renewable energy, total annual feed to grid, and total annual power from grid.