5. Application
Currently, many companies have invested in on-site power
plants. The investment criteria in the past mostly focused
either on base-load satisfaction, on a subsidized sell to the
public grid or on combined power-heat applications.
Therefore, the installed systems were uniquely planned and
designed for a permanent usage facing a fixed production
program respectively energy demand. By integrating the
concept of energy flexibility, the production program
especially the scheduling can be enabled to adapt the energy
demand of a factory to volatile generation or variable prices.
Therefore, the KPIs of the on-site generation need to be added
to Enterprise Resource Planning (ERP) and Manufacturing
Executions Systems (MES) in order to match the production
based demand and the available on-site generation costefficiently.
Including the current price information from the
public grid, an integrated energy supply orientated production
planning can be performed. In first applications using SAP
based structures, the process from production program
planning to scheduling was executed successfully.
6. Summary and Prospects
Integrating the on-site generation into production planning
and control systems is an important step when coordinating
the energy supply in production. Its practical implementation,
however, is facing various challenges. Although the software
SAP ERP allows defining energy storages as storage locations
without any problems, it does not allow a storage period in the
SAP standard. A redefinition of material variations can be
implemented as well, but the inventory management
distinguishes all the variations, so the system specific term
material is lost [17]. Updates and add-ons for the SAP
standards are necessary and are already in the making.
In order to ensure an optimized energy supply of the
production, a master plan is needed. This master plan
combines the obtaining of energy from the public grid with
the on-site generation. Even if on-site generation can have
cost advantages compared to buying electrical energy from
the public grid; in some scenarios, covering the demand with
an aligned combination of both can a resource- and costefficient
solution.