This study explored the impacts of electricity allocation protocols on the life cycle greenhouse gas (GHG) emissions of electricity consumption. The selection of appropriate electricity allocation protocols, methodologies that assign pools of electricity generators to electricity consumers, has not been well standardized. This can lead to very different environmental profiles of similar, electricity-intensive processes. In an effort to better represent the interconnected nature of the U.S. electrical grid, we propose two new protocols that utilize inter-regional trade information and localized emission factors to combine generating pools that are sub-or supersets of one another. This new nested approach increases the likelihood of capturing important inter-regional electricity trading and the appropriate assignment of generator emissions to consumers of local and regional electricity. We applied the new and existing protocols to the U.S. primary aluminum industry, an industry whose environmental impact is heavily tied to its electricity consumption. Our analysis found GHG emission factors that were dramatically different than those reported in previous literature. We calculated production-weighted average emission factors of 19.0 and 19.9 kilograms carbon dioxide equivalent per kilogram of primary aluminum ingot produced when using our two nested electricity allocation protocols. Previous studies reported values of 10.5 and 11.0, at least 42% lower than those found by our study.often use average emission factors (EFs) at various levels of aggregation (WRI/WBCSD 2007;US EPA 2008). However, depending on which average EF is used, two identical processes can be assessed as having dramatically different emissions from consuming the same quantity of electricity. Average EFs also smooth over differences in emissions between regions.We propose a new methodology that creates a local EF for electricity based on the weighted average of local and regional

Many efforts to develop walking and running robots utilize a boom or other device to catch the robot when it falls, sense the position of the robot, and constrain the robot to operate in a two dimensional plane. However, publications usually focus on the robot, and the restraint system remains undocumented. Each group must start from scratch, or rely on word of mouth to build on the experience of others. This paper focuses solely on the artificial restraint system for legged robots, with discussion of various design options and documentation of existing systems.

No abstract