The application of solar cookers offers energy that can be harvested by using Thermoelectric Generator (TEG) modules to produce electricity. This study examines the effect of the temperature difference (ΔT) on the output power of a TEG by utilizing heat from a solar cooker. The main objective is to analyze TEG as a solar-heat power source and to assess how strongly ΔT influences the TEG’s electrical performance as well as the effectiveness of its thermal design. Using a quantitative experimental method, tests were carx ried out with a solar cooker as the heat source, two cold-side cooling methods (a fan and water), and periodic observations from 09:00 to 15:00 over three days. To reduce thermal resistance, a copper plate was used as a heat spreader; its high thermal conductivity improves heat flow to the TEG and helps maintain a larger ΔT. The results show peak performance at 12:00: fan cooling produced 2.293 mW at ΔT = 22.19 °C, whereas water cooling reached 3.099 mW at ΔT = 26.63 °C; water cooling consistently outperformed the fan at all observation times. This study confirms that the larger the ΔT, the higher the TEG power output. For comparison, a conventional stove delivers much higher power because it achieves a larger ΔT about 8.82 mW (low flame), 30.56 mW (medium flame), and 47.82 mW (high flame) while the best solar-cooker condition (strong sunlight) produced about 3.27 mW. Overall, ΔT is the key determinant of TEG performance on a solar cooker; maintaining a high ΔT through water cooling and the use of a copper plate increases the generated power, although the absolute output remains below that of a conventional stove, which can achieve a larger ΔT