Worldwide geographical mapping and optimization of stand-alone and grid-connected hybrid renewable system techno-economic performance across Köppen-Geiger climates

In the last years, a significant interest in research in stand-alone (SA) and grid-connected (GC) photovoltaic (PV)-wind hybrid renewable energy systems (HRES) is observed for their complementary in the satisfaction of the electrical energy demand in many sectors. However, direct comparisons between the techno-economic performance of two system modes under the same operating conditions are rarely carried out. Additionally, most of the researches are limited to specific weather conditions. This work aims to bridge the lack of this type of investigations providing a worldwide techno-economic mapping and optimization of SA and GC PV-wind HRES to supply the electrical demand of an office building district. For this purpose, energy and economic optimization problems were formulated to find the optimal SA and GC systems worldwide among 343 HRES system power configurations located in 48 different localities, uniformly divided in the sub-group of the Koppen classification. The energy reliability and economic profitability of optimal systems were geographically mapped worldwide. In general, the energy or economic optimizations of SA HRES do not lead to highly profitable systems; instead, feed-in-tariff to sell the energy in excess assures viable GC HRES in many localities. However, economically optimal SA and GC HRES, respectively, do not everywhere comply with the threshold value of 70% of the satisfied energy required by the load and are characterized by a high level of energy exchanged with the grid. The study highlighted that the most suitable climate conditions to install a SA HRES are: (i) Toamasina (Madagascar) from an energy point of view, with 76% of load satisfied and 76% of the energy generated utilized to supply the load; (ii) Cambridge Bay (Canada) from an economic point of view, with 11.1% of the capital cost recovered each year; instead, the most suitable climate conditions to install a GC HRES are: (iii) New Delhi (India) from an energy point of view, with 48% of energy exchanged with the grid per each kWh required by the load; (iv) Lihue (Hawaii, United States) from an economic point of view, with 24.3% of the capital cost recovered each year.