Oyenubi, A. and Oyeyipo, O. O. (2026) Cost-carbon trade-offs in green infrastructure: A case of Nigeria. Journal of Engineering, Design and Technology, 24(3), pp. 805-830. ISSN 1726-0531
Abstract
Purpose – This study aims to address the lack of a structured framework for understanding how stakeholders in developing countries, particularly Nigeria, balance construction cost constraints with sustainability objectives in green infrastructure projects. This gap is intensified by limited green financing, unstable market and decision-making approaches that overlook both economic and qualitative sustainability factors. To address this, the study proposes a consensus-based method for assessing cost−carbon trade-offs and identifying key drivers that align cost control with improved sustainability outcomes. Design/methodology/approach – A qualitative, three-round Delphi study was conducted with 20 purposively selected experts, including public clients/regulators, consultants, contractors, financiers, suppliers and academics. The first round involved a focus group discussion to generate initial themes, while the second and third rounds used content-validated questionnaires refined from Round 1. The reliability of the items was assessed using Cronbach's alpha (threshold = 0.70), and consensus was measured with Kendall's coefficient of concordance (W), which increased across rounds, indicating convergence. Findings – Four interlocking themes were identified as critical to cost–carbon decision-making in Nigerian green infrastructure delivery: perceived value of sustainability; cost-sustainability strategies; institutional and regulatory levers; and knowledge and capacity development. These insights were synthesized into an integrative framework emphasizing evidence-based persuasion, strategic collaboration, supportive regulation and capacity development. Originality/value – This study is novel in presenting a framework for cost–carbon decision-making in green infrastructure projects. It advances construction management knowledge by revealing how cognitive, institutional, strategic and human-capability factors interact to achieve sustainable project outcomes, thereby offering both theoretical and practical significance.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | construction management; cost–carbon trade-offs; Delphi method; green infrastructure; life cycle cost; Nigeria; procurement |
| Index terms: | life cycle cost, management knowledge, capacity development, developing country, construction cost, project outcome, questionnaire, Delphi method, regulator, Nigeria, focus group, public client, collaboration, green infrastructure, evidence, methodology, regulation, cost control, financing, strategy, decision-making |
| Subjects: | management, Geography, sustainability and resilience, evaluation and assessment methods, research methods, social and economic development, decision analysis, data collection methods, project completion, development economics, financial and cost management, sociology, economic analysis, professional development, political science |
| Topics: | Information Management, Geographical Context, International Construction, Project Management, Governance, Research Practice, Stakeholder Management, Business Strategy, Human Resources, Urban Studies, Cost Management, Organizational Design, Risk Management |
| Descriptive scope: | 5 PCTEA |
N.B. Descriptive scope is a count of how many of the five facets of empirical research are indicated by the words used in title, abstract and keywords. It is not intended as a judgement on the research; merely a count of the kind of word we would expect to indicate Phenomenon, Concepts, Theoretical framing, Empirical techniques, Analytical techniques. If all five are present, then a code of “5 PCTEA” will indicate this. If you feel the coding for this record is questionable, we welcome discussion around the terms we matched or the way we categorized them. The facet you would expect may not be coded, or a facet may be coded inappropriately. This can also bear on a larger question, of which facets should be treated as defining in construction management research. Please get in touch, and we will look at it. More details here