Author(s): Enyinna Gregory Chimere, Oguzie Joy Okwuchi. C, Ogbonnaya Blessing Nmesoma, Okereke Godson & Okpala Chidiogo Adanna,
Application of Monte Carlo Simulation in evaluating the cost associated with developing green building projects was carried out through distribution and collection of questionnaires from constructions workers in Owerri Metropolis. Relative Importance Index was deployed to determine relative importance of the numerous reasons why delay happens in the construction of green building which is associated with time and cost overrun. Cost of development of green buildings was evaluated to encourage building developers to adopt green building development projects because of their energy friendly nature that helps to preserve the Ecosystem via low level emissions that leads to enhanced energy efficiency and also limit harmful effects of buildings in ecosystems. However, engaging in this sort of project is not without risks attached especially in a country like Nigeria where the green building projects are not yet very common Thus evaluating cost of developing green building projects in Nigeria using Monte Carlo Simulation which was assessed through Microsoft Excel (version 2018) . The study also adopted the survey research design for and also adopted Owerri as the research area for the simulation. Descriptive statistics were adopted for the study in their order of prevalence through the Relative Important Index (RII) rating. Several risks were computed and the results show that non availability of labour was the most prevalent issue since the workers were not used to green building while the other factors such as cost factors, material availability, administrative skills, policies and codes as well as the limitations in communications. Monte Carlo Simulation was used to give several predictions which helped in forecasting Cost of foundation, Material Cost, Labour Cost, Equipment Cost, Wall facility Cost, Widow design Cost, Cost of green building development as well as Cost of Interior.