Modern petroleum reserves consist of heavy and extra-heavy crude oils characterized by high viscosity and low API gravity, significantly impacting pipeline transportation and increasing pressure drop and pumping power requirements. This study focuses on developing a sustainable thermal heating system to reduce the viscosity of heavy crude oils by integrating solar energy with the phase change material. A pilot heating station, having two operating modes, was designed to maintain crude oil within the operating viscosity limit of less than 400 cp. For mode 1, the results demonstrated that from dawn until late afternoon, the abundant solar energy, captured effectively by the solar collector (FPSC), was sufficient to raise the oil temperature to 54.32 ℃ or higher, maintaining it below the critical threshold of 400 cP. In mode 2, the phase change material RT44HC was employed to ensure the system’s sustainability from the late evening to the early morning hours. It was found that the absorbed solar heat by the PCM was insufficient to increase the crude oil temperature to the desired level. To address this challenge effectively, the FPSC integrated into this mode. The system ensured efficient and sustainable heavy crude oil transportation management, leveraging the peak solar energy periods to maintain oil viscosity within optimal transportation parameters.