Procedure Model “Purchase”

According to the procurement process, two different roles of purchasers need to be taken into account. On the one hand, there are governmental organizations and large enterprises that use structured tendering procedures in large scale procurement projects, on the other hand, home users as well as small and micro enterprises must not be ignored. Indeed, the potential to pursue sustainability goals of the first group is much higher.


Nowadays, especially larger companies and governmental organizations do have a sustain-ability report, which can influence procurement processes. To visualize the typical steps of purchasing software products while focusing on sustainability issues, we created an exemplary procedure model that fits into the purchase category.

In both cases, governmental as well as in private environments, the requirements of the software product need to be defined first. Apart from technical requirements, the Life Cycle Costs (LCC) of the product need to be taken into account. In that way, the entire product life cycle of the software product and the entire supply chain is already addressed in the procurement process. The results of the first step are criteria comprising mandatory and optional requirements. It is advisable to create checklists for the entire software product with these criteria. The checklists can re-gard energy efficiency criteria, environmental criteria, as well as social criteria and complete the non-functional criteria for a software product.

Examples of Efficiency Criteria

  • Memory consumption
  • CPU-intensity
  • Software induced resource consumption
  • Software induced energy consumption

Examples of Environmental Criteria

  • Portability
  • Data medium
  • Download size
  • Level of dematerialization

Examples of Social Criteria

  • Working conditions
  • Manuals

For further criteria refer to our life cycle thinking inspired software product lifecycle.

Based on the checklists and criteria, the procurement process goes on with selecting possible bidders, evaluating bids, and finally concluding the contract or rather buying the soft-ware product. That means that the persons responsible for purchasing must not lose sight of the sustainability issues during the whole process. In practice that means e.g. that appropriate criteria, like the company’s social and environmental responsibility, their commitment to international labor standards [1] or the application of environmental management systems [2], are integrated into the selection process.

The complexity of the complete procurement process differs from case to case. It depends on the environment in which the software product will be used. In case of micro and small enterprises, as well as home users, the process will be less comprehensive. Generally, standard software will be chosen. For standard software products, energy efficiency and hardware obsolescence criteria can either be used as technical requirements or as award criteria. Usually, their limit values and weighting in the selection procedure must be documented in the tendering documents. This implies that these cannot be altered after the tendering procedure has started. It is possible that a larger enterprise also decides to purchase standard software products, but custom software products are more common in this surrounding. For custom software, non-functional requirements like energy efficiency or requirements addressing mitigation of IT infrastructure obsolescence, which may be included by the tendered software product, can be defined.

In contrast to the hardware side, so far there are no labels for green and sustainable soft-ware. We advocate a label for software products similar to the ENERGY STAR® [3] that indicates that a software product is energy efficient or meets certain sustainability requirements. Additionally, information on sustainable issues should be easily obtained especially for home users. Such information could be printed on product boxes or product sheets so that the user can make informed decisions on which product fits their needs best.

In order to accomplish this, it is necessary to provide measurement methods and typical usage scenarios to endow bidders and users with acceptable maximum measurement values. In this context, we propose a method to measure and rate software-induced energy consumption.


  1. International Labour Organization: International Labour Standards by Subject [2012-02-09]
  2. Environmental management systems ISO 14001
  3. ENERGY STAR® is a registered trademark owned by the United States Environmental Protection Agency (EPA);