Environmental sustainability and improvement options for agribiomass chains: Straw and turnip rape

Abstract

Biofuels are seen as an effective means to reduce greenhouse gas (GHG) emissions of energy production. However, the cultivation phase of agribiomass-based biofuel production in particular can cause significant GHG emissions and additional environmental problems, such as water pollution and biodiversity loss. In this study, the aim was to develop a comprehensive environmental sustainability framework for agribiomass chains. The chosen environmental impact categories (climate change, eutrophication, soil erosion, soil organic matter decline, ecotoxicity, biodiversity, use of non-renewable resources, water use, and production efficiency) were selected based on literature and the views of energy companies and interest groups. The framework was tested with two Finnish agribiomass chains: barley (Hordeum vulgare L.) straw (for combustion) and turnip rape (Brassica rapa ssp. oleifera DC.) (for biodiesel). Relevant improvement options were identified and their impact reduction potential was assessed.The GHG emissions of both selected bioenergy sources were less than those of their fossil fuel references. Critical challenges for both studied agribiomass chains currently include eutrophication, soil organic matter decline and the use of non-renewable natural resources. The indicator values could be markedly improved by the selected improvement options, of which the most important is optimal yield. Better distributions of manure and soil fertility improvement (carbon stock and pH) were identified as the most important long-term goals for improving sustainability.