Assessment of key financial supports for promoting zero energy office buildings investment in Thailand using sensitivity analysis

Thailand has pledged to be carbon neutral by 2050 at the UN Climate Change Conference (COP26). Promoting all-new buildings to be net-zero energy consumption within 2030 is a strategy to achieve the goal. The previous works have revealed that policymakers and related stakeholders’ supportive strategies could significantly contribute to promoting the zero-energy buildings (ZEB) investment. Moreover, another big challenge in improving high-energy-efficient buildings is the high initial cost and uncertainties of the future costs. As far as we know, no studies have investigated an effect of such a change in economic and relevant costs on the financial benefits of the ZEB project in Thailand. Such parameters are a significant barrier to decision-making on ZEB investment. Consequently, the guidance for affordable financial feasibility and supportive measures could significantly promote ZEB projects. This study used sensitivity analysis to assess the variations of future costs, including initial cost, energy price, maintenance & operation cost, interest rate, and discount rate, influencing the project’s NPVs and the global costs of three representative office buildings. The analyses showed that the total cost was strongly sensitive to the investment cost, with a maximum reduction of 15.76% when the investment cost was reduced by 20%. The NPV was significantly influenced by energy price, with the variations ranging from 2.83% to 15.12%. ZEB development in large buildings provided more financial profitability than in small buildings. Finally, the key effective financial parameters and the key persons responsible for supporting financial measures were proposed to promote ZEB project investment in Thailand. The increase in energy prices and the decrease in initial cost, especially the cost of the air-conditioning systems, will increase investment returns. However, such increments in energy price also affect small and low-income enterprises. For future implementations of ZEB, policymakers should investigate suitable measures and financial incentives.