238 publications from this institution
A large fraction of the developing world utilizes biomass fuels for cooking. Air pollution from these stoves represents a significant health hazard. Electric cooking has been identified as a potential method to deliver clean, cost-effective, cooking in the developing world, with particular emphasis on electric pressure cookers (EPCs) that are more energy-efficient than cooking in unpressurized vessels. Most EPCs in use today are designed for fast, on-grid, cooking using large heating elements, and it is unclear how these large, cyclic, power loads would impact minigrids. This study uses an electro-thermal model to investigate how a range of EPC power ratings would impact their use in minigrids. Results indicate that the lower efficiency of lower-power units increases minigrid energy requirements in a non-trivial way relative to higher-power units. Finally, this study also indicates that periods of higher power consumption for higher-power units occurs infrequently, and thus minigrids may be capable of handling EPCs for cooking staples such as rice and beans.
Gas-driven pneumatic controllers (PCs) and actuators used in all natural gas sectors vent uncombusted natural gas to the atmosphere during operation and contribute approximately 20% of methane emissions from the natural gas supply chain. In this study, multiday measurements were utilized to better characterize PC emission rate profiles. Emissions from 72 PCs were successfully measured at 16 gathering compressor stations for an average of 76 h each between June 2017 and May 2018. These measurements are the first known multiday recordings of emissions of PCs in situ at operating natural gas facilities. These measurements revealed previously unidentified emissions behaviors. A review by an expert panel identified 30 PCs (42% of measured devices) that exhibited abnormal emissions behavior, including 25 of 40 intermittent-vent PCs, 5 of 24 low-bleed PCs, and 0 of 8 high-bleed PCs measured. Abnormally operating PCs had emissions substantially higher than the emissions of those operating normally. For intermittent-vent PCs, abnormally operating PCs showed average emission rates of 16.1 standard ft3 h–1 (scfh, whole gas) versus 2.82 scfh for normally operating PCs. Sampling simulations also indicate that measurements of ≥24 h are necessary to quantify emissions to within 20% [11–31%] of a PC's long-term average emissions. Due to potential biases in sample size and diversity and corrections for measurement errors, we recommend these data be utilized for only a qualitative understanding of PC behavior and not for developing emission factors.