What is Load Forecasting?
Electrical energy cannot be stored. It has to be generated whenever there is a demand for it. It is, therefore, imperative for the electric power utilities that the load on their systems should be estimated in advance. This estimation of load in advance is commonly known as load forecasting. It is necessary for power system planning.
Power system expansion planning starts with a forecast of anticipated future load requirements. The estimation of both demand and energy requirements is crucial to an effective system planning. Demand predictions are used for determining the generation capacity, transmission, and distribution system additions, etc.
Load forecasts are also used to establish procurement policies for construction capital energy forecasts, which are needed to determine future fuel requirements. Thus, a good forecast, reflecting the present and future trends, is the key to all planning.
Purpose of Load Forecasting
The following are some of the purposes of load forecasting.
- For proper planning of power system.
- For proper planning of transmission and distribution facilities.
- For proper power system operation.
- For proper ﬁnancing.
- For proper manpower development.
- For proper grid formation.
- For proper electrical sales.
Classification of Load Forecasting
The load forecasting can be classiﬁed as:
- Demand Forecasting and
- Energy Forecasting
This is used to determine the capacity of the generation, transmission, and distribution system additions. Future demand can be predicted on the basis of fast rate of growth of demand from past history and government policy. This will give the expected rate of growth of load.
This is used to determine the type of facilities required, i.e., future fuel requirements.
Depending on the time period of interest, a speciﬁc forecasting procedure may be classified as:
- Short term
- Medium (intermediate) term.
- Long term technique.
For day-to-day operation, covering one day or a week, Short-Term forecasting is needed in order to commit enough generating capacity formatting the forecasting demand and for maintaining the required spinning reserve.
Long Term Forecast is done for 1-5 years in advance in order to prepare maintenance schedules of the generating units, planning future expansion of the generating capacity, enter into an agreement for energy interchange with the neighboring utilities, etc. Two approaches are available for this purpose – Peak Load approach and Energy Approach. We will discuss them later.