Brownfield, Greenfield, Colorfield: The Road to SAP S/4HANA

In the retail sector, this is primarily about 

• implementing an individual omnichannel business model,
• placing the target groups and their requirements at the centre of the corporate strategy through consistent customer centricity,
• aligning the system architecture with the MACH principles (microservices, API-first, cloud-native, headless),
• merging technologies and business processes productively with each other,
• maintaining a clean core in order to be able to react flexibly and quickly to market requirements.

There is no way around the changeover for retailers and all other companies that use SAP ERP. A current survey shows the expectations of companies with regards to moving to SAP S/4HANA.

• Future viability: Most companies (46%) want to secure their technology in good time and position themselves for the future.
• Harmonisation: More than a third (33%) aim to optimise and harmonise their business processes.
• Innovation: For some companies (21%) it is about securing the basis for further business innovations and end-to-end transformations.

A large majority (85 %) of the SAP customers surveyed, however, are also concerned that a transformation project will in any case be accompanied by considerable risks, a high resource input and high costs.

Brownfield, Greenfield and Colorfield are the three main approaches for moving to SAP S/4HANA. Which one to choose depends on factors like these: 

• how complex the existing IT infrastructure and how extensive the existing, individual interventions in the SAP core are,
• what needs the company has for the new ERP solution in terms of optimising function, efficiency and cost-effectiveness,
• which development intentions the company is pursuing not only in the short term, but also in the medium and long term.

The three migration approaches attempt to address the individual requirements to such an extent that a swift, secure, comprehensible and financially viable move to a consistent environment with SAP S/4HANA is possible.

• Brownfield is the migration approach for companies that are satisfied with the processes in their existing SAP solution and have been able to leave the system core largely untouched. Under this condition, it is possible to convert data and processes to the new environment of S/4HANA without setting up a completely new system. 
• The Greenfield approach aims to rebuild the SAP system on the "green field". In other words, it is not converted, but newly implemented, with the migration project running parallel to everyday business without interfering with productive operations. Companies that want to use the migration as an opportunity to clean up their complex SAP systems that have grown over the years, to optimise their future processes to a greater extent or to free them from burdensome ballast benefit from the greenfield method.
• The Colorfield approach leads companies to the middle ground between a Brownfield and Greenfield migration. The aim of the hybrid approach is to transfer proven components of the legacy system to SAP S/4HANA and to replace obsolete components and inflexible processes that cannot be optimised further with new ones.

Advantages

• Migration projects based on the Brownfield principle are supposedly clear and low-risk, but only if the aforementioned prerequisites are met in the initial situation.  
• For existing customers who were able to work well with the SAP standard processes and functions in the past, the transformation is easy to understand and the new solution is easily accessible.
• Due to the largely 1:1 transfer of existing processes, users can familiarise themselves more easily and only then deal with the conception of new features. 

Disadvantages 

• The changeover in the Brownfield approach is only possible with a "big bang". The conversion of the entire ERP system with its interface landscape (e.g. eCommerce and stationary applications) must be set live in one go. Nothing must go wrong with this approach, therefore it must be extensively tested in advance.
• Extensive preparatory work on the ECC system is necessary. For example, one should be prepared for business partner processing, the new G/L and other topics. Technical requirements must also be met. The Brownfield approach can only be carried out from a certain release (EhP).
• A system migrated according to the Brownfield principle initially "only" restores the old functionality in a new environment. 
• Optimised functions and innovative features are not yet available at first, with minor exceptions such as the use of Fiori Apps, so that the new solution will only unfold its full potential gradually over time.
• Among the retail companies, only 15% can carry out a Brownfield migration as the necessary system requirements are not in place.

Advantages

• The new implementation within the framework of the Greenfield migration offers the highest degree of future security, as the previous SAP system is freed from old burdens and deficiencies that hinder innovation.
• Databases and processes can be set up fresh and according to the latest technological findings and requirements.
• The new SAP core again offers the necessary flexibility for integrating the latest applications via standardised interfaces.

Disadvantages

• In order to achieve the desired increase in efficiency after the SAP S/4HANA Greenfield implementation, processes and data management must be analysed, redesigned and set up. As you have to leave familiar paths, this poses a challenge. 
• In addition to the involvement of internal IT experts, a Greenfield implementation usually also requires the specialist departments to participate in the optimisation and redesign of the processes.
• In the case of a Greenfield implementation, a longer project duration and higher costs are to be expected.

• The Colorfield approach combines the advantages of Brownfield and Greenfield migration and at the same time tries to circumvent their disadvantages.
• Based on the processes of the legacy system, new processes can be implemented or existing ones changed. The investment protection on existing processes and developments is given. The necessary data migration can be carried out selectively or, depending on the migration procedure, also with historical data. The balance between preservation and renewal also ensures a balanced expenditure of time and money.
• During the move, ongoing operations are not impaired and the release of new features can take place gradually (no big bang necessary).

This is already feasible today with modern tools and, in addition to helping you decide on the right approach, it also paves the way for innovative and seamless retail processes - from customer interaction to back-end processes in the company.