Background: The construction sector has a 10-year time span to become 50% circular and to reduce carbon emissions by 49% compared to 1990. This time span is even shorter for public clients, as the Dutch government functions as launching customer, and strives make its own tenders circular in 2023, and carbon neutral in 2030. Utilising public procurement to reduce carbon emissions and increase circularity is not yet common. This is because individual clients have limited buyer power to influence the market, insufficient knowledge or funds, and a lack of ability to take the lead in promoting wanted changes in procurement. Existing concepts and tools to tackle this issue, still have a limited effect on the implementation of sustainable public procurement.

Therefore, the Dutch government proposed buyer groups as a means to harmonise the market demand of public clients, aimed to tackle the existing problems of sustainable procurement. These pilot buyer groups are a relatively new phenomenon in the public pre-procurement process.

Purpose: This study is aimed to create insight into how (semi-) public clients can successfully establish or join a suitable buyer group, and how they can successfully cooperate and harmonise demand within buyer groups.

Research question: How can (semi-) public clients successfully implement buyer groups in the pre-procurement process of construction projects, to minimise carbon emissions and maximise circularity?

Methodology: A dual-method approach is implemented. Firstly, a literature review is conducted to examine relevant existing knowledge related to buyer groups, focusing on aspects of cooperation, legal relationships and legal restrictions. Secondly, case studies are conducted to capture the experience created by pilot buyer groups, focussed on formation, participants, organisational structure, demand harmonisation processes, impact and legal aspects. These case studies are input for a cross-case analysis, which is subsequently used to formulate best practices for buyer cooperation.

Outcomes: This research facilitates public clients with two main outcomes. Firstly, clients wishing to join or establish a suitable buyer cooperation, are supported by an overview of existing literature on this topic. Many different forms of buyer cooperation exist, each with different purposes, considerations and limitations. An overview of these forms is briefly visualised into a decision tree. Secondly, clients already participating in a buyer group are supported with best-practices from case studies. These best-practices provide findings and recommendations regarding buyer group cooperation and the demand harmonisation process.

Limitations: This research specifically focussing on buyer groups in the pre-procurement process of Dutch (semi-) public clients, that aim to reduce carbon emissions and increase the circularity of construction projects. This research is thus not directly applicable to clients with different context or different characteristics, or to buyer groups in other industries and sectors. Furthermore, this research excludes substantive considerations on actual procurement processes, the content of contracts, theory on circularity or carbon emission reduction, theory on conducting market consultations, the perspective of suppliers and the process of steering innovation.