Reducing emissions and air pollution from informal brick kilns: Evidence from Bangladesh.

We present results from a randomized controlled trial in Bangladesh that introduced operational practices to improve energy efficiency and reduce emissions in 276 "zigzag" brick kilns. Of all intervention kilns, 65% adopted the improved practices. Treatment assignment reduced energy use by 10.5% (P-value <0.001) and decreased CO2 and PM2.5 emissions by 171 and 0.45 metric tons, respectively, per kiln per year. Valuing the CO2 reductions using a social cost of carbon of 185 USD per metric ton, we find that the social benefits outweigh costs by a factor of 65 to 1. The intervention, which required no new capital investment, also decreased fuel costs and increased brick quality. Our results demonstrate the potential for privately profitable, as well as publicly beneficial, improvements to address environmental problems in informal industries. Editor's summary: In South Asia, bricks are typically made in coal-fired kilns that are a major contributor to greenhouse gas emissions and air pollution in the region. Regulating such informal industries is difficult and limited by state capacity in many low- and middle-income countries. However, Brooks et al. found that simple modifications to operational practices at "zigzag" kilns in Bangladesh reduced their energy use, emissions, and fuel costs while improving brick quality. Uptake of the intervention was high (65%) and even sought out by almost 20% of kilns in the control group. The short-term economic benefits and lack of capital investment of the intervention likely contributed to its uptake and success. —Bianca Lopez INTRODUCTION: In many low- and middle-income countries, it is commonly believed that weak state and regulatory capacities limit the ability to reduce pollution and mitigate climate impact. In Bangladesh and across South Asia, most brick manufacturing takes place in informal, traditional coal-fired kilns. These kilns are among the largest sources of greenhouse gas emissions and air pollution, leading to an enormous public health burden. RATIONALE: In Bangladesh, efforts to improve the brick kiln industry over the past 30 years have had limited success. Our past work suggests that a correctly operated zigzag kiln (a traditional kiln type that accounts for 81% of the sector) can not only improve efficiency but also increase kiln profits. However, most zigzag kilns in Bangladesh are incorrectly operated, leaving these social and private benefits unrealized. Improving energy efficiency presents an alternative strategy to reduce emissions and pollution while also delivering productivity gains. RESULTS: We developed a low-cost intervention to improve the energy efficiency of zigzag kilns and conducted a randomized controlled trial (RCT) of the intervention among 276 kilns in Bangladesh. Our study included a control arm and two intervention arms (a "technical" arm and a "technical+incentive information" arm). All kilns assigned to both intervention arms received information, training, and technical support to adopt operational improvements that improve fuel combustion and reduce heat loss in the kilns. These improvements specifically targeted how coal is fed during the firing process and how bricks are stacked inside the kiln, along with several other aspects of operation. Kilns assigned to the "technical+incentive information" arm also received explicit information regarding the business rationale for incentivizing workers to adhere to the new practices. There was high demand for the intervention, with 65% of intervention kilns adopting the intervention's recommended firing and stacking practices. Notably, 20% of control kilns also adopted these practices, bolstering the interpretation that demand was high. There were no differences in adoption between the two intervention arms and no use of incentives or benefits in the "technical+incentive information" arm. We studied the intention-to-treat (ITT) effect of random assignment to the intervention, as well as the impact of the intervention after adjusting for compliance using an instrumental variables (IV) framework. Among compliers, the intervention led to substantial reductions in the amount of energy used to fire bricks (23%) and corresponding reductions in carbon dioxide (20%) and particulate matter with a diameter of <2.5 µm (20%). These gains were achieved without any evidence of a rebound in energy demand. Kiln owners also benefited financially from the intervention; production of the highest quality category of bricks increased in intervention kilns and spending on fuel per brick declined. The primary costs of the RCT were the training costs and technical support costs throughout the season. Using a social cost of carbon of 185 USD per metric ton to value the reductions in CO2 emissions, we find the benefits of the intervention outweighed the costs by a factor of 65 to 1, and that these reductions were achieved at an average cost of 2.85 USD per ton. CONCLUSIONS: Our study demonstrates that meaningful reductions in emissions by traditional kilns are achievable, even in the absence of stronger regulations, if they can be made financially attractive to private kiln owners. Adoption and impact of energy-efficient kiln operation practices.: This figure shows the percent of study kilns that adopted the improved brick stacking and fuel feeding practices across control and intervention arms (left), and the corresponding effect of the intervention on energy consumption (middle) and CO2 emissions (right). For energy consumption and CO2 emissions, the ITT effect of random assignment to the intervention (left) and the effect of the intervention after adjusting for compliance (using an IV framework) (right) are estimated with regressions that control for randomization strata and are presented as the percent change relative to the control mean. [ABSTRACT FROM AUTHOR]