Trade-off between life cycle cost and greenhouse gas emission in construction projects

In the past, sustainability was not a major concern for different construction stakeholders such as:  clients, consultants, designers and contractors.  However, with increasing social and environmental challenges, sustainability in project management began to gain importance. Sustainability challenges brought forth the need to develop and implement projects in which Life Cycle Assessment (LCA) was recommended. In a project, Life Cycle Costing (LCC) provides a decision support in selecting a suitable alternative to execute a work package based on its financial benefits as opposed to LCA, in which decision is based on the Environmental Impact Assessment (EIA) of a product or assembly. Application of LCC is limited in construction projects because it is time intensive, costly, computationally exhaustive, less standardized, and its benefits are not well recognized. Hence there is a need to combine the life cycle costing and the cost on account of environment impact so that the stakeholders can appreciate the LCA in a better manner.  Accordingly an attempt is made here to integrate the LCC with EIA so that the financial benefits and sustainability in construction projects are understood simultaneously. For this a case study is taken up which demonstrates the trade-off between the LCC and EIA in terms of Greenhouse Gas (GHG) emission in CO2-equivalent. The LCC and GHG for different construction activities using different resource combinations are evaluated using the ATHENA impact estimator 5.2 and the Genetic Algorithm (GA) based optimization model is used to establish a trade-off between LCC and GHG. The proposed model may help the stakeholders to study the long term analysis of construction projects not limited to construction phase alone.