Green IT: no good scenarios without analyzing history

Planning effective IT energy savings requires a good understanding of a company’s IT background. This information is crucial for fine-tuning a company’s energy profile after choosing the best audit methodology and performing an initial audit. A company’s energy profile serves as the basis for identifying IT energy savings scenarios. Below are some examples of these scenarios that companies can deploy and manage using a software interface.

energy savings scenarios for the work environment

The challenge is to adapt IT equipment’s energy use to reflect the amount of time users spend at work. The main scenarios for the work environment are listed below.

  • nightly shutdown: shutting down computers at night, when most users are not at the workplace, is one of the easiest ways to save energy. For example, shutting down computers between 9 PM and 8 AM can generate energy savings of up to 40%.
  • weekend and holiday shutdown: this involves shutting down equipment on weekends and holidays. It is generally a large source of savings, as employees are rarely at the workplace during these times. Savings can reach 30%.
  • lunch hour standby: in this scenario, computers are placed on standby when employees leave for lunch. This scenario places more constraints on users than the previous scenarios. Energy savings generated by one hour of standby each day can reach 5%.
  • periodic standby during the day: this is a dynamic scenario in which machines are put on standby when not in use. It can serve as a substitute for a lunch hour standby scenario, since it also helps generate savings throughout the workday. Energy savings can vary between 5% and 10%.
  • user presence standby: under this active scenario, user machines are shutdown when the user is not on company premises. Identification of a user’s presence can occur with the company’s badge system or an application on the employee’s smartphone. Machines will then start up or shut down based on the user’s presence. This scenario represents a large source of energy savings. However, setup is more complicated because it requires user training and authorization. It can offer the same benefits as a night, weekend and holiday scenario. Energy savings can exceed 50%.

energy savings scenarios for IT infrastructure

The goal when reducing the energy consumption of IT infrastructure is to adapt energy consumption to the need for IT resources, all without impacting the services the IS division commits to company business. The main scenarios for IT infrastructures are listed below.

  • shutdown of unused resources: this scenario involves shutting down resources that are not being used, such as ghost servers. Software detects equipment not in use and shuts it down. Significant energy savings can be had with low impact on processes. Energy savings vary between 5% and 20%, depending on the infrastructure.
  • modifying equipment power: through this scenario, equipment runs at varying power levels. Applied to servers and virtual environments, it helps match a machine’s power to the task it is performing. Energy savings vary between 20% and 30%, depending on the infrastructure.
  • adapting resource management to network needs: this is a dynamic energy management scenario for virtual environments depending on their activity. It helps maximize the use of virtual machines to perform a set of tasks. Energy savings can reach 15%.

Energy savings scenarios are applied in the context of an IT energy policy, and they should involve all of a company’s stakeholders. A financial simulation of these scenarios should occur before and after launch to evaluate energy savings. The next and last article in our series will be devoted to financial simulations.

For more information, read the following White Paper: Reducing the Energy Consumption of IT Equipment.


This post was originally published in French here.

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Alexandre Chupin

I'm a consultant in the sustainable development division of Orange Consulting, resonsible for our energy audit service.  I'm interested in the intersection of sustainable development and information technology.  I like to travel and discover other cultures' perspectives.