2. Caveats
Some of the recommendations in this text are discussed controversial, for instance: powering down a device, when it's not in use. This may save power, but not under all circumstances. Also it may have other additional ecological costs, e.g. the life time of the device can be shortened.
I don't have enough technological knowledge to make a decision between these alternatives. Also some alternatives might be rated differently by different persons. So finally the decision what to choose is up to you. Anyway if you have better alternatives please let me know.