Impact of government subsidies on household biogas use in rural China

In this paper, we evaluate empirically the impact of biogas subsidies on household biogas energy use in rural China. Special attention was given to the problem of sample selection bias in assessing the impact of subsidies on biogas energy use because biogas subsidies often change the propensity for installing biogas digesters. Using data from a large-scale household survey, the results indicate that biogas subsidies did promote the construction of biogas digesters. The results suggest that a 10 percentage point increase in subsidy-cost ratio would lead to a 3% increase in digester installations. We also found that biogas subsidies correlated negatively with average time of digester use. A 10 percentage point increase in the subsidy-cost ratio would result in a 4.3% reduction in the average working time of digesters. These results suggest that the net effect of the current subsidy policy on rural household biogas use was near-negligible. Indeed, a 10 percentage point increase in the subsidy-cost ratio resulted in a mere 1.15% increase in biogas use. These findings indicate that biogas subsidies have possibly not been targeted effectively at households that would actually prefer to use biogas energy.