---
title: "Small area load forecasting method"
subject: "Transmission and Distribution System Design"
chapter: 6
key: "semester_8/transmission_and_distribution_system_design:small-area-forecasting-method"
source: https://www.bctengineer.com/q/semester_8/transmission_and_distribution_system_design/small-area-forecasting-method
site: BCT Engineering
---

# Small area load forecasting method

Transmission and Distribution System Design · Chapter 6: Electrical Load Characteristics and Load Forecast

- Asked in: 2073 Bhadra, 6 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/transmission_and_distribution_system_design/small-area-forecasting-method
- Whole chapter: https://www.bctengineer.com/md/semester_8/transmission_and_distribution_system_design/chapter-6

## Question

Explain one of the small area forecasting method.

## Short answer

The simulation method divides the service area into cells, scores vacant cells for suitability, allocates regional growth to the highest-scoring cells, then converts future land use to load using load density. It yields a spatial load map for substation siting and feeder routing.

## Answer

Small area forecasting predicts the amount, location and timing of load growth in small zones. The two main methods are trending and **simulation (land-use)**. The simulation method is explained below.

#### Simulation (land-use) method

The service area is divided into small cells (e.g. a grid of 1–10 hectare squares). Instead of extrapolating past load, the method simulates how land use will change and then converts land use into load.

```text
 Base land-use map + zoning plan
           |
           v
 Global (system) forecast of growth
           |
           v
 Allocate growth to cells
 (preference / suitability scores)
           |
           v
 Future land use in each cell
           |
           v
 x load density (kW/ha) per class
           |
           v
 Cell load map --> substations, feeders
```

**Steps:**

1. **Data collection:** present land use of each cell (residential, commercial, industrial, agricultural, vacant, restricted), roads, railways, rivers, zoning by-laws, population and planned projects.
2. **Global forecast:** total growth of the whole region (customers or kW) is found from econometric/trending studies.
3. **Suitability (preference) scoring:** each vacant cell is scored for each land-use class from factors such as distance to roads and town centre, nearby land use, slope, and planned infrastructure.
4. **Allocation:** the global growth is allocated to the highest-scoring cells year by year, so that land use changes in a realistic spatial pattern.
5. **Load conversion:** future load of each cell = Σ (area of each land use × load density of that class), with end-use load curves giving the coincident peak.
6. **Calibration:** results are checked against present loads and the global forecast.

**Merits:** forecasts load in undeveloped areas, gives a load map useful for siting substations and routing feeders, and allows "what-if" scenarios.

**Demerits:** needs large data and computing effort.

(The **trending method**, by contrast, fits an S-curve (Gompertz) to each area's past load; it is simpler but fails for areas without load history.)

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is the basic idea of the simulation (land-use) small area forecasting method?
   A. Fit an S-curve to each area's past load
   B. Simulate how land use changes in each cell, then convert land use to load
   C. Multiply last year's load by a fixed growth rate
   D. Copy the load of a neighbouring utility
   Answer: B. The method does not extrapolate past load; it forecasts future land use per cell and converts it to load using load densities. (Key point: Idea of simulation method)

2. How is the global (system) growth distributed among the cells?
   A. Equally to every cell
   B. Only to the cells that already have the highest load
   C. To the highest-scoring cells from suitability (preference) scores, year by year
   D. Randomly each year
   Answer: C. Each vacant cell is scored for each land-use class and growth is allocated to the best-scoring cells, giving a realistic spatial pattern. (Key point: Allocation of global growth)

3. How is the future load of a cell found?
   A. Sum of (area of each land use x load density of that class)
   B. Number of roads x population
   C. Global growth divided by number of cells
   D. Past peak x Gompertz factor
   Answer: A. Future land use of the cell is multiplied by the kW/ha load density of each class and summed. (Key point: Load conversion)

4. Why is the simulation method preferred over trending for undeveloped areas?
   A. It needs less data
   B. It needs no computing
   C. It can forecast load where there is no load history and allows what-if scenarios
   D. It ignores zoning
   Answer: C. Because it works from land use, it can predict load in vacant areas and test scenarios, at the cost of large data and computing effort. (Key point: Merit of the method)

## Related in Transmission and Distribution System Design

- [Small area forecasting with load growth curve](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Asmall-area-load-growth-curve) — Transmission and Distribution System Design, chapter 6
- [T/F: simulation method for small area forecast](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Atf-simulation-small-area-forecast) — Transmission and Distribution System Design, chapter 6, asked 2×
- [Demand forecasting steps at load center](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Ademand-forecast-load-center-steps) — Transmission and Distribution System Design, chapter 6
- [Methods of load forecasting](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Aload-forecasting-methods) — Transmission and Distribution System Design, chapter 6

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- [Short-term load forecasting method](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Ashort-term-load-forecasting) — Power Plant Design, chapter 2
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- [Accurate load forecasting and system security](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Aload-forecasting-benefits-security) — Power Plant Design, chapter 2