Redistributing pollution: Exposure implications of a shift toward distributed electricity generation in California

Small-scale distributed electricity generation (DG) technologies have been promoted for their many benefits as compared to the traditional paradigm of large, centralized power plants. To evaluate the implications for human inhalation exposure resulting from a shift toward DG, I utilized Gaussian dispersion modeling to conduct a GIS-based inhalation exposure assessment of existing and hypothetical power-generation facilities in California. Most of the dissertation examines twenty-five existing central station power plants (CS) compared to selected DG technologies hypothetically deployed in the downtown areas of the 11 most populous cities in California. A complementary analysis compares statewide inhalation exposure resulting from different scenarios of widespread DG deployment in the commercial sector of California in year 2010 to a scenario of no shift toward DG. Metrics employed to summarize the exposure impacts of DG- and CS-based electricity generation include the intake fraction (iF), the intake-to-delivered-energy ratio (IDER) and the population inhalation intake rate. The iF is the fraction of emitted mass attributable to a source that is inhaled by an exposed population. The iF was determined for populations living within 100 km of each source, using an annual cycle of meteorological conditions typical of the long-term observational record and incorporating population-based, lifetime average breathing rates. The IDER is the attributable population intake per unit of electricity delivered to the place of use, computed as an intake fraction multiplied by an emission factor. Intake rate was computed either as the intake fraction multiplied by an emissions rate or as the IDER multiplied by the rate of delivery of electricity to users. Pollutants evaluated include a primary conserved species (primary PM2.5), a primary decaying species (formaldehyde), and a mixed primary and secondary decaying group of species (nitrogen oxides, or NOx). Other important secondary pollutants, such as ozone, were not assessed. The DG technologies considered in this dissertation include natural gas-fired turbines, internal combustion engines and microturbines, fuel cells (with hydrogen supplied by on-site natural gas reformers) and diesel internal combustion engines. Throughout most of the dissertation, post-combustion emission controls were assumed not to be utilized for any DG technology. For most scenarios considered in the statewide exposure assessment, the examined DG technologies were assumed to meet the current California best available control technology standard for NOx (32 mg kWh-1).