This document discusses Microsoft's efforts to improve the energy efficiency of its datacenters. It describes how Microsoft optimizes both the servers and datacenter infrastructure together to achieve the best overall performance per watt and lowest total cost of ownership. Key strategies discussed include increasing server power efficiency, adopting more efficient cooling techniques like air-side economization, standardizing modular component design, and locating datacenters near renewable energy sources. The goal is to continuously reduce datacenter energy usage and costs while scaling to handle growing computing demands.