Introduction

Electricity is a public good that is used for a very broad range of applications. A typical electrical distribution facility in an industry will in general include the following:

• Power distribution systems for manufacturing and process equipment, including indoor sub-station, plant distribution, process control systems, building electrical service systems and protection systems
• Power outlet system for movable equipment, material-handling systems, transportation system
• Auxiliary systems like air-conditioning & refrigeration, compressed air system, lighting, fire alarms systems, communication and computer based equipment.
• Maintenance, canteen and medical facilities
• DG sets and/or Co-generation equipment

As electricity cannot be economically stored on a large scale, it has to be produced at the same moment and in the same quantity that is actually requested and has to be transmitted instantaneously from the power generator to the user via transmission lines. Because of these special features, the electricity supply system has to be designed for the maximum expected demand.

However, depending on the power grid supply can be critically when the supply is not reliable and power outage like load shedding are frequent. Generating electricity by Diesel gensets during load shedding is very costly and increases production cost considerably. Therefore, it makes sense to look into the utilities that demand electricity in order to find wastage.

Based on this principle, Demand Side Management techniques have been developed to influence the electricity demand and increase the utilisation and operating efficiency of existing supply facilities, thus delaying the need for new capacity and reducing the operating costs.

Electric Load Management or simply called Load Management is a specific method of controlling the peak load in the electrical system in order to produce a constant demand. It can be defined as any action to change the load profile in order to gain from reduced total system peak load, increased load factor and improved utilisation of valuable resources like fuels or generation, transmission and distribution capacity.

Practicing load management has many advantages. Some of them are mentioned in the following:

• Load management avoids the requirement to increase transformer, cable sizes and generator capacity
• Load profile is generally more efficient, controlling peaks
• Decreasing peak load reduce need for bigger backup systems like diesel generators.
• Steady load without extreme peaks prevents diesel generators from damage through overloading
• As peaks are likely to coincide with periods of most expensive electricity prices, either individual industries will become more competitive or prices will be forced downwards
• It is environmentally more acceptable due to an effective use of resources.

Under “Energy Efficiency” more technical details are given on how to practice effective load management.

Payback of energy saving options

Experience from the past have shown that energy auditing of electrical system is highly profitable. The following table shows some of the energy saving options with the respective payback of investment: