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Measuring usage of cookstoves with sensors in Darfur

Development Challenge

Three billion people cook and heat their homes using open fires and simple stoves burning biomass and coal. Roughly 4 million people die prematurely from illness attributable to the household air pollution from cooking with solid fuels. 

Context

Improved cookstoves have the potential to substantially reduce exposure to harmful emissions from cooking. However, adoption and impacts of these cookstoves are usually measured with surveys, which are known to highly error-prone.

Evaluation Strategy

Stove Use Monitors (SUMs) are sensors that can help verify that cookstoves are being without relying on surveys or observation.  This project deployed SUMs on the Berkeley Darfur Stove in Darfur, Sudan. Since 2005, 44,000 of these cookstoves have been donated or sold in Darfur, primarily within internally-displaced people’s camps. To better estimate the impacts of this large project, the team employed SUMs sensors to accurately measure the factors affecting adoption. The challenges of working in Darfur make it an ideal case for use of SUMs. The SUMSs experiment began on July 28th, 2013, with the distribution of groups of 36 stoves to 5 administrative units (180 stoves total). Baseline surveys were completed at the time of dissemination, and follow up cellphone-based surveys were completed 1-3 months later. Over the course of the three months, sensors activated for different durations and at different sampling frequencies.

Results and Policy Implications

The sensors estimated that at least 71% of participants used the stove more than 10% of days that the sensor was installed on the cookstove; this is compared with 95% of survey respondents reporting that the Berkeley-Darfur Cookstove was their “primary cooking stove.” Compared to sensor-measured data, surveyed participants overestimate adoption both in terms of daily hours of cooking and daily cooking events (p<0.001). Average participants over-reported daily cooking hours by 1.2 h and daily cooking events by 1.3 events. These overestimations are roughly double sensor-measured values. Data reported by participants may be erroneous due to difficulty in recollection, courtesy bias, or the desire to keep personal information obscure. Interestingly, the follow-up survey itself created a very significant increase in cookstove adoption among the 29% of cookstove recipients who did not use the cookstove much before the follow-up. 83% of prior “non-users” converted to “users” after the follow-up survey. The researchers believe this may be due to cookstove familiarization and social conformity. 

Another paper has recently been accepted n ES&T. It will be uploaded to the website when it gets published.