This document describes the challenges of accurately reporting energy usage costs and carbon savings across different geographic locations with variable electricity tariffs. It explains how factors like electricity prices, carbon dioxide emission rates, and utility rebates vary in different places. The NightWatchman 6 software addresses this by allowing users to define tariffs for locations that specify the cost per kWh, carbon conversion rate, and utility provider. This enables NightWatchman to accurately calculate and report costs, emissions, and savings at each location.