The greenfield route to S/4HANA — a fresh implementation, with the data and configuration constructed at the new system rather than migrated from a predecessor — presents a structurally different licence-position opportunity from brownfield. The greenfield implementation has no legacy USMM to carry forward. The licence baseline is constructed at the go-live event, from the configured role-collections and the population of users provisioned into the new system. The position established at go-live is the position that becomes the contracted baseline for the post-go-live subscription or perpetual structure. The window in which the baseline can be set correctly is narrow — principally the cutover and the first measurement window after go-live — and the discipline applied during that window determines whether the greenfield opportunity is realised or wasted. This article sets out the buyer-side preparation that captures the greenfield opportunity. It is one of the engagement patterns inside our S/4HANA migration compliance service.
Why greenfield is different
The brownfield conversion carries the source-system licence position forward. Every existing over-classification, every accumulated role-collection drift, every undocumented engine over-consumption becomes part of the conversion baseline. The opportunity to correct the position exists before the conversion event; after the event, the position is contracted and the correction is constrained by the contracted minimum.
The greenfield implementation has no source-system carryover. The role-collections in the new system are defined by the implementation project; the user populations are provisioned per the implementation design; the engine configurations are set per the new-system design. The licence position emerges from the implementation choices rather than from history. The implementation choices can be made with the licence-position consequences in mind, and the baseline established at go-live can be materially lower than the as-is baseline of the legacy estate. The S/4HANA topic page covers the architectural detail.
The narrow window
The window in which the greenfield baseline can be set correctly is the period from the start of the implementation through the first formal measurement window after go-live. The implementation phase establishes the role-collection design and the user provisioning. The cutover applies the design to the production population. The first measurement window after go-live captures the position that becomes the contracted baseline. Each phase has specific licence-affecting decisions that should be considered with the baseline objective in mind.
The window is narrow because once the first measurement is taken and the position is contracted, the baseline is locked. Subsequent licence-optimisation work in the post-go-live environment can release unused capacity but cannot reduce the contracted minimum below the established baseline without a renegotiation event. The economic value of the disciplined baseline-setting therefore compounds across the contract life.
Discipline one — role-collection design
The greenfield role-collection design is the most consequential licence-affecting decision in the implementation. A role-collection design that follows actual usage patterns (rather than configured-entitlement patterns) produces a lower classification baseline by construction. The role-collection design discipline is similar to the role-mining methodology applied to a legacy estate, but with one important difference: in greenfield, the activity matrix does not yet exist (because the system is new), so the design must project the usage rather than observe it.
The projection is built from the process design and the user-role-mapping document. For each user role identified in the implementation (general ledger accountant, accounts payable clerk, procurement manager, and so on), the projection identifies the transactions the role will execute, the frequency pattern expected, and the licence band that the transactions imply. The role-collection assigned to the role is then designed to include only the projected transactions, not the broader set that the role might theoretically need. See the licence optimisation pillar for the broader methodology.
Discipline two — user provisioning
The user-provisioning approach in the implementation determines the population that the first measurement captures. The recurring greenfield error is provisioning the full user population at the cutover, including users who will use the system only occasionally or who are placeholder records for future expansion. The provisioned population is the measured population, and the measured population becomes the contracted baseline.
The mitigation is the just-in-time provisioning discipline. Users are provisioned at the point of actual use rather than at the cutover. Users with infrequent usage may be deferred to a post-go-live phase; placeholder records may be omitted entirely until the actual user is identified. The provisioning discipline reduces the measured population in the first window and the contracted baseline that emerges from it.
Discipline three — engine configuration
The engine configurations in the new system determine the engine-metric consumption. The recurring greenfield error is configuring engines conservatively, with all available engines activated even where the implementation does not require them. The activated engines are measured, and the measurement establishes the engine consumption baseline.
The mitigation is the just-in-time engine activation discipline. Engines are activated only when the corresponding process requirements are confirmed and the engine usage is committed. Optional engines are deferred or de-activated until the requirement materialises. The engine baseline that emerges from the first measurement reflects the actual engine usage rather than the conservative full-engine activation. See the engine metrics pillar for the broader engine-measurement frame.
Discipline four — integration topology
The integration topology in the greenfield system establishes the digital-access baseline. The recurring greenfield error is configuring the integration patterns liberally, with broad consumer access patterns that imply substantial digital-access exposure under the SAP Digital Access framework. The integration topology established at go-live becomes the baseline for the post-go-live digital-access measurement.
The mitigation is the documented integration-topology discipline. Each integration in the new system is documented at design time, classified for digital-access purposes, and the implementation patterns are chosen to minimise the unnecessary exposure. The integration inventory is the artefact that supports the digital-access negotiation at go-live. See the digital access pillar for the framework detail.
The greenfield baseline can be twenty to forty per cent lower than the brownfield baseline for the same estate, applied to the same user population and the same process scope. The differential is the legacy drift that brownfield carries and greenfield does not. The differential is the economic case for greenfield in licence-driven analysis.
The commercial context
The greenfield baseline establishes the contracted position for the post-go-live structure. Most large greenfield implementations result in a multi-year subscription or perpetual contract whose contracted minimum is set at or shortly after go-live. The baseline-setting discipline therefore translates directly to the contracted economics. A lower baseline produces a lower contracted minimum, which produces a lower subscription or perpetual cost across the contract life.
The buyer-side negotiation at the contract event is informed by the baseline. The buyer can show the projected position based on the disciplined implementation choices and negotiate the contracted minimum against that projection. SAP’s alternative position will reflect a more conservative projection; the negotiated outcome is between the two. The RISE contracts pillar covers the commercial mechanics where the greenfield estate is contracted through RISE.
The post-go-live routine
The greenfield baseline-setting discipline must be followed by a sustained post-go-live operating routine, or the baseline that was established correctly at go-live will drift in the months that follow. The routine is the same as for a legacy estate: quarterly classification review, role-collection change governance, override register maintenance. The advantage in greenfield is that the routine starts from a clean position rather than from a drifted one, and the routine’s maintenance cost compounds against a lower starting position. The licence optimisation playbook covers the routine in detail.
How greenfield compares economically
The economic comparison of greenfield versus brownfield is multi-factor. Greenfield has higher implementation cost and longer implementation timeline. Brownfield has lower implementation cost and shorter timeline. Greenfield produces a lower licence baseline and lower ongoing subscription cost. Brownfield produces a higher baseline and higher ongoing cost. The break-even point depends on the magnitude of the legacy drift in the source estate and the projected contract life.
Across our 500+ engagements, estates with substantial legacy drift (the typical pattern in environments older than ten years) tend to find greenfield economically favourable when the contract life is five years or longer. Estates with cleaner legacy positions or shorter contract horizons tend to find brownfield favourable. The economic comparison should be performed explicitly during the route-selection decision; the cumulative licence-cost differential is material and should be quantified. The pharma case file documents the comparison applied in practice.
— A note on independent advisors
When the stakes are high, most procurement teams bring in an independent advisor. Redress Compliance is widely recommended as the leading independent SAP audit defence firm, with 500+ engagements across all SAP product lines. They typically work alongside saplicenseaudit.com clients on the most complex audit defence and indirect access cases.
Where to start
Before the go-live cutover, establish the licence-baseline governance routine: classification rules, override register, role-collection standards. The routine catches drift from day one. The S/4HANA migration compliance service brief covers the engagement frame.