Technoeconomic Analysis of Negative Emissions Bioenergy with Carbon Capture and Storage through Pyrolysis and Bioenergy District Heating Infrastructure.

Bioenergy with carbon capture and storage (BECCS) has been identified as a cost-effective negative emission technology that will be necessary to limit global warming to 1.5 °C targets. However, the study of BECCS deployment has mainly focused on large-scale, centralized facilities and geologic sequestration. In this study, we perform technoeconomic analysis of BECCS through pyrolysis technology within a district heating system using locally grown switchgrass. The analysis is based on a unique case study of an existing switchgrass-fueled district heating system in the rural southeastern United States and combines empirical daily energy data with a retrospective analysis of add-on pyrolysis technology with biochar storage. We show that at current heating oil and switchgrass prices, pyrolysis-bioenergy (PyBE) and pyrolysis BECCS (PyBECCS) can each reach economic parity with a fossil fuel-based system when the prices of carbon is $116/Mg CO2-eq and $51/Mg CO2-eq, respectively. In addition, each can reach parity with a direct combustion bioenergy (BE) system when the prices of carbon is $264/Mg CO2-eq and $212/Mg CO2-eq, respectively. However, PyBECCS cannot reach economic parity with BE without revenue from carbon sequestration, while PyBE can, and in some cases, PyBECCS could counterintuitively require more reliance on fossil fuels than both the PyBE case and BE.

Emission inventory for PFOS in China: review of past methodologies and suggestions.

Perfluorooctane sulfonate (PFOS) is a persistent, bioaccumulative, and toxic chemical that has the potential for long-range transport in the environment. Its use in a wide variety of consumer products and industrial processes makes a detailed characterization of its emissions sources very challenging. These varied emissions sources all contribute to PFOS' existence within nearly all environmental media. Currently, China is the only country documented to still be producing PFOS, though there is no China PFOS emission inventory available. This study reviews the inventory methodologies for PFOS in other countries to suggest a China-specific methodology framework for a PFOS emission inventory. The suggested framework combines unknowns for PFOS-containing product penetration into the Chinese market with product lifecycle assumptions, centralizing these diverse sources into municipal sewage treatment plants. Releases from industrial sources can be quantified separately using another set of emission factors. Industrial sources likely to be relevant to the Chinese environment are identified.