关键词：新能源与高效节能；能源效率；电力设备；能源优化
摘 要：Increasing power consumption of IT infrastructures, growing electricity prices, and ecological awareness are major reasons for a change towards green IT. At the same time, the demand for steadily increasing computational performance remains unbroken. However, optimizing IT equipment in regard to energy saving frequently becomes a trade-off between the energy optimization and the system performance. This chapter defines relevant terminology regarding IT energy efficiency and presents an overview of IT components causing energy consumption. Additionally, it provides a summary and categorization of existing energy saving techniques and energy efficiency metrics as well as an analysis of the impact of energy saving measures on performance. By comparing different energy efficiency metrics, we see that there is no uniform unit to quantify IT energy efficiency. We show that the application of energy saving methods has to be carefully chosen for individual services, as possible energy savings and impairment of performance differ significantly between different energy saving methods.