Energy Management

Energy may be used in a variety of forms such as electricity, gas, heating oil and wood fuel. The majority will be consumed in operations such as machinery operation, compressed air generation, heating and lighting.

Energy specific advice and publications can be obtained free of charge from organisations such as the Energy Efficiency Best Practice Programme and the Carbon Trust: www.thecarbontrust.org.uk. A few examples of areas worthy of consideration are listed below.

General

Take meter readings during a period when the factory is closed to highlight unnecessary usage and leaks. For example, read the water, gas and electricity meters at 5 pm on a Friday and again before work starts on Monday morning
Measure the amount of energy which is consumed by the site as a whole and specific processes
Make people aware of how much they are wasting. Rather than talking in terms of kWh and other units which are hard to envisage, convert information to easily understandable figures. Examples include: by leaving this machine on overnight, you waste enough energy to power your home for one month, or the wastage is equivalent to the energy required to make 50 cups of tea etc.
Energy management systems provide a good degree of control over key energy using processes. They allow the remote setting of timers and thermostats, thereby reducing unnecessary usage and making it more difficult for people to interfere with energy consuming systems
Is there any benefit in working overtime before the shift rather than at the end, e.g. due to a cheaper tariff?

Compressed air

A common misconception is that compressed air is cheap. In fact it is the most expensive form of energy used on site and will typically account for 20% of the total energy bill in a manufacturer. Compressed air is generated using electricity and the inefficiency of the generation process means that each kWh of compressed air is ten times as expensive as each kWh of electricity. Consequently, compressed air can cost upwards of 50p/kWh. It is important that everyone is aware of the cost
A site walk around during lunch time enables you to listen for leaks. An independent survey of 47 industrial sites in the UK found an average compressed air leak rate of 39% (Envirowise, 2001a).
There are many examples of unnecessary air use on furniture sites. For instance, air lines which are left permanently open to blow dust away from a machine or air lines which are used to blow-down people and workpieces. Such practices not only waste a significant amount of money but they also lead to higher than necessary dust exposure levels for employees, thereby contravening the Control of Substances Hazardous to Health Regulations 2002.
Check the timing of compressors. If they are switched on and off by a time switch, does this take into account weekends and clock changes? Is there scope to turn the system off before the end of the working day to allow the last half hour of production to use up the stored air?

Electricity

Motors and drives can account for two-thirds of electrical energy used by industry (Envirowise, 2001a). Motors can cost up to one hundred times as much to run over their ten-year life as the initial purchase cost, hence it is worth selecting higher efficiency motors.
Ensure that motors and drives are switched off when not in use
Reduce the load (e.g. drive train maintenance) and motor speeds whenever possible. Variable speed drives can save 30-40% in many situations.
Can wood dust extraction systems be segmented so that only the required sections are operated. This is particularly useful when a limited amount of overtime is being worked
If coating booths are in occasional use, consider the installation of an idling switch for the motor. Thus, when the spray gun is placed on its hook, the booth continues at normal speed for a short time afterwards (e.g. 2 minutes) before switching off or dropping to a lower speed. The 2 minute lag allows residual solvent to be removed and avoids the motor constantly starting and stopping.
Consider the installation of movement sensors for lights in areas which are less frequently used
The cleaning of windows and sky lights allows the use of natural light

Heating

Heating generated by electricity will cost five times as much as that provided by gas. If possible, remove electric heaters from offices. If only one or two individuals are complaining of the cold, advise them to wear warmer clothes!