Air quality assessment of a mass deployment of microgrids

Microgrids are emerging to mitigate the degradation in grid resiliency and reliability resulting from an increasing frequency of grid outages. Because microgrids incorporate a local source of power generation, the production of electricity is shifting from a centralized to distributed topology, thereby installing power generation resources and the concomitant emissions into heavily populated urban air sheds and residential communities. In this paper, the air quality and public health impacts of a mass deployment of microgrids in an urban air shed are assessed. Candidates to become microgrids are identified for both the near- and long-term deployment, and two microgrid scenarios are considered, differing by the 24/7 prime source of power: (1) combustion gas turbine (CGT)-based microgrids and (2) zero-emission fuel cell (FC)-based microgrids complemented by solar PV and battery energy storage. Spatially and temporally resolved emissions from the microgrids are input to an air quality model and assessed for health impacts. The results show that (1) a mass deployment of CGT-based or FC-based microgrids in both the near- and long-term has a relatively small impact on air quality, (2) the health impacts are nonetheless significant for CGT-based microgrids due to the large and dense population of the area, and (3) disadvantaged communities are disproportionately impacted with the deployment of CTG-based microgrids. For example, near-term deployment of CGT-based microgrids results in an increase in the incidence of premature mortality (1 to 5 incidences per month) and an increase of $33 to $56 million per month in health costs. Deploying zero-emission FC-based microgrids mitigates the adverse health impact, prevents several incidences of premature mortality, and results in saving of ~$36M per month rather than a cost per month of ~$50M.