Häufig gestellte Fragen
What is the difference between greenfield and brownfield in an ERP implementation?
Greenfield refers to a complete rebuild of the ERP system "on a greenfield site": processes are redesigned, legacy data is carried over only selectively and in cleansed form, and existing customizing is deliberately left behind. Brownfield, by contrast, is a technical conversion of the existing system in which configurations, in-house developments and historical data are largely retained in order to continue ongoing operations as unchanged as possible. Greenfield thus aims at process optimisation and a clean restart, brownfield at continuity and risk minimisation. Both terms describe the approach to the implementation, not the product itself.
When is greenfield the better choice and when brownfield?
There is no blanket recommendation, as suitability depends on data quality, process maturity and risk profile. Greenfield is a good fit when processes need overhauling anyway, the data base is heavily burdened or the legacy system deviates far from the standard, because technical debt and custom solutions can be shed this way. Brownfield makes sense when the existing solution fits well functionally, master data is well maintained and the risk of process changes would be high. Decisive for the overall assessment are the total cost of ownership over several years, not the pure project price alone.
What does the bluefield or Selective Data Transition approach mean?
Bluefield — a brand term coined by the SNP Group that is closely related to the approach SAP calls Selective Data Transition — is a hybrid middle path between greenfield and brownfield that decouples the system conversion from the data transfer. A new system is set up into which only selected processes, configurations and historical data are migrated in a targeted manner, while outdated elements are left behind. This allows proven parts to be retained while obsolete structures are cleaned up at the same time, without redesigning the entire business process. The approach is considered attractive for complex scenarios such as carve-outs, mergers or restructurings because it avoids the classic big-bang cut.
How do greenfield and brownfield differ in effort, duration and cost?
Brownfield projects are generally faster and less expensive, as existing configurations and data are technically carried over rather than developed anew; however, they frequently drag along existing customizing and its maintenance burden. Greenfield requires more organisational effort and change management because employees have to learn new processes, but it enables higher data quality and a lean standard core. Common industry reference figures for SAP S/4HANA transformations cite roughly 12 to 15 months for brownfield and around 15 to 21 months for greenfield, although the actual duration depends heavily on the source system. These ranges are reference points, not guaranteed project timelines.
Does the greenfield/brownfield question only matter for SAP S/4HANA?
No — although the terms became widespread through large SAP migrations, they describe a general procedural pattern of any ERP implementation. The choice between a rebuild and modernising the existing system also arises when switching other systems, for example from Microsoft Dynamics NAV to Dynamics 365 Business Central. In the SAP environment, the topic gains additional urgency from the end of mainstream maintenance for SAP ECC and SAP Business Suite 7 — according to SAP, at the end of 2027, followed by paid extended maintenance until the end of 2030 and a limited transition option for selected customers beyond that. The underlying decision logic based on data quality, process maturity and risk, however, applies regardless of vendor.