A review on energy efficiency and demand response with focus on small and medium data centers

Data centers are the backbone of a growing number of activities in modern economies. However, the large increase of digital content, big data, e-commerce, and Internet traffic is also making data centers one of the fastest-growing users of electricity. The total energy consumption of data centers corresponded to almost 1.5% of the global electricity consumption and has an approximated annual growth rate of 4.3%. Therefore, it is very important to increase the energy efficiency in data centers with actions such as power usage management, server consolidation, energy-efficient components and systems, as well as demand response programs and renewable energy sources. Small and medium data centers account for more than 50% of the total electricity consumption in this sector. In fact, surveys indicate that this data center profile waste more energy than larger facilities. Nevertheless, existing studies tend to be focused on the energy-related issues for large data centers rather than small and medium data centers. Therefore, through a meticulous state-of-the-art literature review of data centers energy efficiency and demand response perspectives, this paper aims to present how an intensive energy consumer, such as small and medium data centers, can become more efficient from the energy point of view and how they can take advantage of demand response programs to decrease costs and to cooperate with the grid to ensure higher reliability and sustainable development goals.