This presentation will describe Enron Energy Services $100M Performance Measurement Center developed to manage energy data for commercial and industrial accounts and energy activities. George Hernandez managed the Performance Measurement Center and designed the monitoring systems. Numerous commercial Energy Information System vendors presented hardware and software products for Enron's use and testing. Energy Information System (EIS), which monitor and organize building energy consumption and related trend data over the Internet, have been evolving over the past decade. This technology helps perform key energy management functions such as organizing energy use data, identifying energy consumption anomalies, managing energy costs, and automating demand response strategies. George will describe these systems, and review their strengths and weaknesses.