Field Evaluation of a Photovoltaic–Wind Turbine–Battery DC Microgrid with a Concentrated Solar Thermoelectric Branch

Field evidence for hybrid renewable microgrids remains scarce, and reliability indices measured on operating systems are rarely qualified by their operating conditions. This paper reports on the design and field evaluation of a 24 V direct-current microgrid that combines photovoltaic (PV) and wind generation with lead-acid storage and a parabolic-dish thermoelectric branch on a shared bus. Reliability was assessed from metered field campaigns (696,595 records) and a design-basis suite using Loss of Power Supply Probability (LPSP), Loss of Load Expectation (LOLE), and two storage-independent indices. At the metered load, wind reduced battery-supplied energy by 17.9% (13.5% at night) and generation adequacy LPSP from 47.9% to 39.4% by generating at night and under low irradiance. Under a 140 W design-basis load, wind reduced LPSP from 4.18% to 0.93%, but the same load over a different resource window (calendar period of measured weather) yielded 24.1%, showing that reliability indices depend jointly on load, storage, and resource window. For the thermoelectric branch, diagnostic elimination showed that manual-tracking dwell time and optical-interface coupling govern output; repositioning the modules raised delivered power from 13.11 W to 50.96 W.