C5. Carbon Conversion Cycles: From Cultivation to Construction

From agricultural residues to building materials: C5 turns carbon-rich biomass into fibres, insulation and biochar. The project connects rural and urban economies, cuts construction emissions and develops circular value chains for sustainable building.

In short

C5 investigates how carbon-rich agricultural residues can be transformed into circular building materials. The research connects agriculture and construction through a cultivation-to-construction approach. Across six pilot actions in Northwest Europe, we convert residual biomass into:

high-quality fibres and filaments for structural applications
materials for insulation and composites
biochar for construction uses, purification and carbon storage

The project builds on earlier European collaboration and develops solutions that can be transferred to other regions.

Need and relevance

Rural areas in Northwest Europe face limited economic opportunities and growing environmental pressure. At the same time, the construction sector remains a major source of greenhouse gas emissions. C5 starts from the question of how both challenges can be addressed together.

The research shows how agricultural residues can gain new value in construction. This creates new income opportunities for rural areas, while urban regions gain access to circular and bio-based materials. C5 also explores how phytoremediation can restore polluted soils to productive use. In this way, the project responds to ecological, economic and societal needs at the same time.

From approach to impact

C5 combines alternative cropping systems such as hemp, willow and agroforestry with advanced biomass conversion. Through the pilot actions, we investigate how different residue streams can be processed into useful construction products across three quality levels. In parallel, we develop regional public-private-community partnerships, training activities and a digital recommender system that helps stakeholders establish context-specific circular value chains.

The pilot results will lead to three replicable solutions for circular value chains linking cultivation and construction. In this way, the research aims to help reduce emissions from the construction sector, create new economic opportunities for rural areas and build lasting cooperation between regions. C5 therefore contributes both to knowledge development and to a broader transition towards a circular carbon economy.