Comparative study on environmental and economic assessment of straw heating across administrative areas scale of rural China

Winter heating in rural areas of northern China requires about 200 million tonnes of standard coal, of which coal is used as the main heat source, causing serious air pollution and exacerbating the greenhouse gas effect. Abundant “zero-carbon” straw in rural areas is a viable strategy for replacing coal-fired heating. The purpose of this paper is to compare the environmental and economic performance of straw heating scenarios.

The environmental impacts and economic costs of four straw heating models across household, village, township, and county scales were compared through life cycle assessment and life cycle cost methods. In this study, the 24-h heat demand of 1 m² (5.18 MJ) was used as a functional unit.

The results showed that the county scale straw cogeneration (CSC) model exhibits the best environmental performance. The global warming potential (GWP) and primary energy demand (PED) of the CSC model are only 11.17% and 10.82% of the household heating model. Straw heating is preferable at the township scale to the village scale from environmental aspects, and direct combustion heating is superior to gasification. For economic aspects, fuel costs are the highest as a percentage of total costs, and the CSC model has the lowest economic costs, with an LCC of 47% of the HSP model. Replacing 20% of coal with straw for heating can reduce annual emissions by 128 million tonnes of CO₂ equivalent and the energy conservation and emission reduction impact by 0.17 (19.97%) in rural areas of China.

Straw heating reduces the environmental impact as scale increases. At the same scale, straw direct combustion for heating has better environmental and economic performance than gasification. The county scale straw heating model has 89% lower carbon emissions than household scale, and has the best overall performance.