This paper proposes a novel low-power operational amplifier (OPAMP) using amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO TFTs). By introducing dynamic operation, power consumption of the proposed OPAMP has been significantly reduced without compromising with other design parameters like gain, slew rate etc. In addition, common mode feedback (CMFB) and internal frequency compensation have been used to ensure good common mode rejection ratio (CMRR) and stability of the OPAMP, respectively. In order to demonstrate the proposed idea, low power OPAMP is designed and simulated using in-house a-IGZO TFT model in Cadence Virtuoso. Circuit simulations have been carried out at a supply voltage and device channel length of 10 V and 20 m, respectively. From simulations, a gain of 30 dB and unity gain bandwidth of 106.8 kHz with a phase margin of 63 were noticed. The power consumed by the proposed OPAMP is 146.8 W, which is significantly lower compared to the OPAMPs implemented with various TFT technologies. The proposed OPAMP circuit would find potential applications in various real-world large area applications that need flexible electronics with low-power consumption like bio-medical and wearable devices.