Yet, this average value is most suitable for the long-term
estimation concerning the energy supply. In order to allow the
production planning to consider this uncertainty, a
differentiation between continuous and fluctuating power
plants need to be performed by adding a different visual
appearance in the energy plan. Then the share of the uncertain
energy can be pointed out in the total energy amount. The
long-term energy plan helps to take measures, e.g. a long-term
purchase of additional electrical energy from the public grid
or an additional on-site generation system.
Here, the long-term planning of energy storages can be
neglected.
4.2. Short-term Energy Plan Development
A few days before the production start, the production
planning and control system is provided with detailed
information on the energy demand. Using the short-term
energy plan, the information can be compared to the equally
updated and equally more precise data concerning the
projected amount of on-site energy production. Whereas the
characteristic values of the continuous power plants remain
consistent, a new and more specific data can be received up to
four days before the production with regard to the fluctuating
power plants and their estimated energy generation. This four
day horizon is split into intervals of eight hours, just like the
short-term energy plan. Figure 6 shows a short-term energy
plan that contains an aggregated amount of energy.