This paper presents experimental results and analysis of a new high-power Cu/Cu2+ thermogalvanic cell and its comparison with previous results. Past researches were mostly focused on finding the best redox couples and electrode materials [1, 2], however, they generally lacked a comparison of power conversion efficiency (η) dependence on cell geometry. This inspired our interest in exploring the relation of η, internal resistance, maximum power, and cell geometry. Based on previous results , a low internal resistance, variable orientation thermogalvanic cell was designed to achieve the highest power output. Experimental results of the Seebeck coefficient (α = ∂E/∂T), power density, and η of Cu/Cu2+ electrolytes in various molar concentrations showed that 0.7M CuSO4 electrolyte has maximum α and power output of 0.7196 mV/°C and 3.17 μW/cm2, respectively. Power output of the new cell has significant improvement which is 219 times greater than previous research. This paper also presents economical aspects of Cu/Cu2+ thermogalvanic cells relative to ferri/ferrocyanide cells.