A circular approach to energy renovation

Abstract

Our world and environment is facing a multitude of complex and intertwined environmental problems. Man made climate change, caused by anthropogenic greenhouse gas emissions and causing an array of negative environmental effects. The raw material input and throughput currently necessary to sustain our human activities which create large quantities of waste. The built environment plays a large role in both: accounting to 50% of the raw materials used, 40% of the national waste stream, 40% of the total energy use in the Netherlands and 35% of the CO2 emissions. A proposed solution for the waste problem is the shift from a linear economy to a circular economy. A proposed solution for the energy problem is transitioning to a (nearly) zero energy built environment. In this context, the depth of energy renovation of the existing building stock - which poses the biggest challenge for a (nearly) zero energy building stock - and building for the circular economy both needs to grow.

However, in the current policies in place, energy efficiency and high energy performance of buildings are prioritised over circularity. This can unintentionally result in building design and materials that do not lend themselves for circularity. It is not the high energy performance hindering the adoption of circular building design, but the choice of construction technique and materials. Furthermore, there is also a lack of consensus about how circularity in buildings can be assessed, while there are well known methods of assessing energy performance of buildings.

In this research, technical building design(s) for an energy renovation project are examined, implementing both circularity and energy performance ambitions. These building design(s) are assessed on their energy performance on the one hand, and on their circular performance on the other, by use of an assessment method partly based on existing circularity assessment methods and partly redefined and further developed for use in this thesis. The assessment method contains the following performance indicators: MAT1 intensity of material use, MAT2 environmental cost, MAT3 design for disassembly, MAT4 design for circular life cycles and E1 energy efficiency. This assessment is used the answer the main research question: “To what extent can circularity be implemented in the designs of energy renovation projects?”

The technical design(s) and the assessments of the design(s) thus support the scientific knowledge about the codevelopment of circularity and (nearly) zero energy ambitions in renovation projects, focusing on the meso scale of individual buildings. The research also supports the development of consensus about how the level of circularity in buildings can best be measured.