In this chapter, we will discuss briefly the history the "Green calculations", successes and related concepts and a number of practical recommendations made by the community involved in this project.

In this series of lectures we will discuss the physical aspects of the energy consumption of computers: we will discuss, among other things, the Landauer’s limit and and the concept of reversible computations

In this lecture, we will be concerned with Power-Demand Routing (PDR) technique that consists in redistributing a system’s power consumption by rerouting request traffic among cluster servers in the system and, in consequence, in minimizing the total operating cost of the system. The cost can be expressed in monetary units or in terms of pollution. We will model PDR as an optimization problem.

In this series of lectures we will discuss a technique called virtualization of services. We will find out when this technique is economically rationale.

We show a short introduction to Online Algorithm Analysis and present how it can be applied to the problem arising when decision has to be made whether and during how long time one should use cloud instead of buying own computing resources.

We consider some opportunities for energy savings by intelligent compilation of scientific programs. We focus on the following three examples, where energy consumption can be decreased without deteriorating the overall performance: lowering disk speed by extending the prefetching time distance, limiting the number of power state transitions by updating disk layout of data, and decreasing voltage/frequency parameters of the channels of the Network on Chip in multicore processor computations.

In this series of lectures we will discuss the properties of the algorithm "Green Leader Election" and the possibility of its implementation in ad hoc networks.