The energy price as basis for calculation
Energy prices may vary depending on the region, supplier and energy source (gas, oil, district heat, etc.). Energy prices can also vary based on the required amount of energy. For grid-bound energy sources, in addition to the kilowatthour rate (cent/kWh), the (basic) kilowatt-based rate must be considered (e.g., €/month).
The current energy prices for the relevant energy carriers should be determined at the time of calculation based on available market data (gross, i.e. including VAT). These may vary considerably depending on the energy carrier and location. In the case of considerable fluctuations of the energy price, an average value over a sensible period of time should be chosen.
Not only the current but also the future development of the energy price should be taken into consideration. This is done using an annual rate of price increase for energy, which usually lies above the general rate of price increase (inflation) . The future energy price increase should be close to the official forecasts (e.g., 3.5%/a nominal/5.5%/a real) . Since the development of energy prices is uncertain and depends on many factors, it is useful to assess an alternative scenario with greater risk (lower price increase) in addition to the base assumption. In many cases (see information on calculation methods) it is possible to implement the future development of energy prices using mean values taken from the Mean value factors table in dependance of several parameters.