Comparative Environmental Evaluation of Straw Resources by LCA in China

Crop straw, as a widely used biomass resource, can be processed to produce renewable energy and green products. However, about 70% of straw were burned in the open air, causing serious environmental pollution and air pollution. In order to reduce the burden on the environment, the different straw management strategies are comparatively studied and evaluated by applying the life-cycle assessment (LCA) method. Within the system boundary from cradle to grave, three alternative scenarios, including straw particleboard, straw cement-bonded particleboard, and straw direct combustion power generation, are compared with the current common treatment (straw open burning). The comprehensive inventory analysis on each treatment scenario is carried out in-depth, and the corresponding resource consumption and environmental impact of each treatment scenario are calculated, respectively. The LCA results showed that the environmental impacts of reusing crop straw to produce straw particleboard and cement-bonded particleboard (Scenario 1 and Scenario 2) is significantly reduced by 6% and 10%, by comparison with the use of wood resource. Greenhouse gas emissions from straw direct combustion power generation (Scenario 3) processes are reduced by 30% compared with coal power generation. From the environmental point of view, the scenario of straw particleboard product has the smallest impact on the environment, while straw open burning is not an advisable way due to the highest environmental impact from the highest greenhouse gas emissions and acidification effects. From the perspective of energy consumption, the energy consumption for the combustion power generation is the smallest in all scenarios. It is suggested that governments are supposed to construct reasonable scenarios for the straw disposition based on the local development status and condition. The research results can provide scientific guidance for the management strategy of the comprehensive utilization of straw resources.