7. Efficiency in Industrial Use of Energy

Industry uses a large amount of energy to power a diverse range of manufacturing and resource extraction processes. Many industrial processes require large amounts of heat and mechanical power, most of which is delivered by natural gas, petroleum fuels and as electricity. In addition some industries generate waste streams that can be recovered to provide additional energy.

Because industrial processes are so diverse from the cold or low temperature required process to the high temperature required process, it is impossible to describe the multitude of opportunities for energy efficiency improvements in industry. There are a number of processes and energy services that are widely used in many industries. Many depend on the specific technologies and processes in use at each industrial facility. However effective energy management in industry, irrespective of size, technology or process, will increase energy efficiency by at least 5%.

To implement co-generation, decrease process heat level and amount or recover the waste heat from process or utilities provides important Energy Efficiency opportunities in many countries.

Various industries co-generate steam and electricity for subsequent use within their own facilities. When electricity is generated, the heat that is produced as a by-product can be captured and used for process steam, heating or other industrial purposes. Co-generation converts up to 90% of fuel into usable energy.

Advanced boilers and furnaces can operate at higher temperatures while burning less fuel. These technologies are more efficient and produce fewer pollutants. Over 45% of the fuel used by US manufacturers is burnt to produce steam. The typical industrial facility can reduce its energy usage by 20% (according to the US Department of Energy) by insulating steam and condensate return lines, stopping steam leakage, and maintaining steam traps.

Figure12

Global electricity demand [4]

Electric motors are by far the most important type of electric load in industry using about 70% of the consumed electricity. In the tertiary sector, electric motor systems use about one third of the consumed electricity.

Electric motors usually run at a constant speed, but a variable speed drive allows the motor's energy output to match the required load. This achieves energy savings ranging from 3 to 60%, depending on how the motor is used. Motor coils made of superconducting materials can also reduce energy losses. Moreover, motors can also benefit from voltage optimisation.

Industry uses a large number of pumps and compressors of all shapes and sizes and for a wide variety of applications. The efficiency of pumps and compressors depends on many factors but often improvements can be made by implementing better process control and better maintenance practices. Compressors are commonly used to provide compressed air which is used for sand blasting, painting, and other power tools. According to the US Department of Energy, optimising compressed air systems by installing variable speed drives, along with preventive maintenance to detect and fix air leaks, can improve energy efficiency by 20 to 50%.