Both terms originate from the field of software development and from software migration projects. Both the greenfield approach and the brownfield approach describe two different approaches and strategies for how and under what conditions software projects can be successfully implemented. Recently, the pending migration to S/4HANA in many places has breathed new life into both terms.
Originally, the terms brownfield/greenfield come from urban planning and other extensive construction projects. Complexity is the keyword, which is why this analogy is used in extensive software projects.
The Brownfield Approach
This term was first mentioned in the software environment by Jenkins and Hopkins in 2008. In a brownfield approach, the user data (documents and data, processes and settings) of the old software system is retained – and transferred to the new software system. It is a migration strategy that appears promising under certain conditions. As long as the legacy system, e.g. SAP ERP 6.0, has largely remained at the standard in its concrete design, chances are very good for a more or less smooth migration to S/4HANA. This is one of the advantages of the brownfield approach. Another advantage is that the scope of change remains low.
However, the disadvantages of the brownfield strategy must also be mentioned: Both the legacy of overly complex processes, for example, remain. Likewise, the brownfield method does not allow the full strengths of the new system to be exploited: It is possible that the best practices – i.e.: recommended actions – for the new system are not possible with the old processes and settings.
Before deciding on the brownfield approach, it is therefore advisable to make a precise inventory and analysis of the business processes as they take place in the legacy system. Subsequently, it must be carefully determined which processes in the old form can be migrated to the new system at all.
The Greenfield Approach
With this strategy, you achieve the full performance of the new system. The greenfield strategy relies on a complete fresh start. To use a metaphor: The project starts anew and proverbially “on the greenfield”.
This path has advantages. Often, many legacy systems have grown historically and have been subject to many adaptations over the course of the last few years. With a greenfield strategy, you gain the advantage of freeing yourself from these legacy burdens. Which data and processes are still needed at all? Which processes can be designed better and more efficiently? Since the greenfield strategy means that the new system is implemented on a different platform, the operation of the legacy system remains unaffected. Until the new system is rolled out, numerous tests can be carried out with key users – so you can quickly discover and eliminate potential errors.
Of course, this approach is time-consuming. However, the Greenfield approach gets you to a system that is specifically tailored to your company’s needs. After implementation, you will not only work on an up-to-date system. At the same time, you also enjoy the advantages of better customizability and benefit from a plus in flexibility, e.g. from S/4HANA.