Purpose
Corporate real estate management (CREM) is complex due to an increasing number of real estate (RE) added values and the tensions between them. RE managers are faced with trade-offs: to choose a higher performance for one added value at the cost of another. CREM research mainly deals with trade-offs in a hypothetical sense, without looking at the characteristics of the RE portfolio nor the specific context in which trade-offs are made. The purpose of this paper is to further develop the concept of real estate value (REV) optimisation with regard to tensions between decreasing CO2 emissions and supporting user activities.

Design/methodology/approach
Mixed method study. REV optimisation between user activities and energy efficiency for police stations in the Netherlands built between 2000 and 2020 is analysed. This is complemented by interviews with an RE manager and senior user of police stations and analysis of policy documents.

Findings
The characteristics of the police station portfolio indicate no correlation between user activities and energy efficiency for the case studied. This is complemented by interviews, from which it becomes clear that there was in fact little tension between supporting user activities and energy efficiency. The performances of these two different added values were optimised separately.

Originality/value
This study combines different scales (building and portfolio level) with different types of data: portfolio analysis, document analysis and interviews. This creates a comprehensive image of whether and how the Netherlands police optimised the two RE values.@en

Construction sectors have a long way to go to realize a circular economy. Many organizational barriers and institutional characteristics inhibit the sector’s transition to circular practices. Nevertheless, within this early phase of the transition, several building projects were realized. This research aims to learn from these frontrunners, in order to distill insights on how to improve conditions at project level. Drawing on ecological systems metaphor, circular building projects in this research are regarded as a system of multiple actors that each perform one or multiple functions: these functions together make up the functional diversity of circular building project. The sum of these functions produces a system service (i.e. circular building elements). Using this perspective to analyze four circular cases, we uncovered five functions that are crucial to realize circular buildings: 1) connecting though vision; 2) matching supply and demand; 3) providing used materials; 4) constructing circular building elements and 5) controlling safety and quality. The functional diversity perspective reveals that functions are to large extent interchangeable between actors. Further applications of the functional diversity perspective could reveal its relevance to support the transition to a circular construction practice and possibly other transition themes. @en