Energy and carbon embodied in straw and clay wall blocks produced locally in the Andean Patagonia

Abstract

The production and use of cereal straw as a base material to make building envelopes in the Andean Patagonian region have been investigated. Energy used and greenhouse gases (GHGs) emitted in local manufacturing of construction materials for walls based on wheat straw were obtained, as well as cropland required for different construction techniques. Two options for the use of straw to fill envelop walls were investigated: the direct use of straw bales, whether in whole or in halves, and the manufacturing of straw-clay blocks. The former has the best thermal conductivity but requires larger cultivation areas to satisfy wall demands, whilst the latter could be an option including moderate thermal efficiency and better cropland performance. Per wall surface unit, energy use and GHG emissions of all straw options were significantly lower compared to fired bricks or to concrete blocks. Furthermore, all straw options analysed result in significantly better thermal performance than current choices of fired bricks or concrete blocks, which are commonly used in the region. The present results show a relevant role of renewable agricultural products in lowering impacts of building materials, as well as options for sustainable production.