Huge potential exists for an integrated solar thermal system that connects several solar thermal plants at various locations to a single centralized energy generation (CEG) system network to meet the demand for heat from various businesses. Effective energy management via optimization has become crucial to increase economic competitiveness, provide more cost-effective energy services, and reduce environmental impacts. Planning and energy management issues include linking every user to a distributed energy resource, a third-party monopoly, and the limited ability of distributed energy resources to compete on pricing and services and set their trading price. The use of locally produced energy is encouraged, and a Peer-to-peer (P2P) competitive energy system is suggested to balance supply and demand. P2P interactions at a larger distribution level are utilized to determine the optimal trading price for an integrated solar thermal system by addressing the financial mechanism. The economic optimization amongst P2P network participants was assessed in terms of the net present value (NPV) and the levelized cost of heat (LCOH). The proposed energy network can enable the model to evaluate transactions, prevent monopolies, and ease access to new distributed energy providers. To demonstrate the suggested approach, a case study of a decentralised competitive heating system at a distribution level is presented. Model simulations were then run to confirm the logic and potential value of the proposed design. In the results, a series of sensitivity analyses were undertaken to investigate the magnitude of the effect of the parameter variation on cost calculation. Simulation findings indicate a minimum solar radiation level of 1,800 kWh/m², a discount rate below 10 %, a lifetime beyond 15 years, and an optimal trading price of 336 USD/m² gross for the system acquisition cost. The study found LCOH with positive NPV values between 55 and 82 MYR/MWh . Hot water trade prices from an integrated solar thermal system can be enhanced by 40 % of the LCOH compared to conventional production. All of these results suggest that an integrated solar thermal system in this context could be promising.