**2.9. Step 5: Creating an energy balance after adjustments (showing the impact of the suggested measures)**

Depending on what kind of problems the auditor has found, different solutions are proposed. There are four principal means of reducing industrial energy costs as shown in Table 2.


**Table 2.** Four principal means of reducing industrial energy costs

It should be noted that the above table concerns energy costs. As regards reduced energy use, load management is not an energy-saving measure as it solely shifts the use of energy to times where it is more appropriate. Moreover, change of energy carrier may be a splendid way to reduce the use of non-renewable resources or energy costs. However, it may not lead to re‐ duced energy use.

compressor already is measured for service reasons, you might be able to allocate the

If you have a common supply for even more processes, try to find the ones with constant power use, like light strips, or constant power use and programmed uptime, like air handling units

Case 4 - A process has more than one energy supply. This is of course a common case. In a building with many air handling units, the units are all doing the same job – they are running the ventilation process. Even if there is a central remote control system for all air handling units, usually the energy use is not logged. The solution is to add up all the air handling units, accepting that your input data quality will range from rated power and estimated uptimes to

You can also have one process with different energy carriers, e.g. a dryer consisting of an electric fan and a hot water heater. If you are not able to register everything, you might be able to use data from one of the carriers to calculate the uptime for the other. For example, the

You might also find two separate electricity supplies to the same unit process for safety reasons, i.e., two separate air compressors connected to two different switchgears to prevent stoppage. Of course you can have more than one supply to a single unit process for other reasons, for example if the electric distribution system has been supplemented because the process needs

**2.9. Step 5: Creating an energy balance after adjustments (showing the impact of the**

Depending on what kind of problems the auditor has found, different solutions are proposed. There are four principal means of reducing industrial energy costs as shown in Table 2.

Energy-efficient technologies Improved efficiency among technologies using energy is one

Load management Reducing power costs by aiming to minimize the power

Change energy carriers Changing energy carriers, e.g. switching from oil to district

Energy-efficient behavior Energy-efficient behavior is a simple measure involving more

energy efficiency in industry.

loads is a common means for industry

heating is a means for industry to cut costs

efficient behavior among staff at the industry

of the foremost and most common means of increasing

energy use by logging the total current to the distribution board.

temperature of the heat exchanger can reveal if the fan is running or not.

more electricity than the original switchgear was designed for.

**Principal means of reducing industrial energy costs Comment**

**Table 2.** Four principal means of reducing industrial energy costs

with constant air volume and an autotimer.

detailed measurements.

130 Sustainable Energy - Recent Studies

**suggested measures)**

**Figure 6.** Energy balance after suggested adjustments [19].

When the impact of the proposed measures is calculated, a new balance is presented (Figure 6). The new balance can have two different purposes: It can show the potential for changes in the energy use or it can show the calculated impact of the measures. The potential for energy efficiency can be estimated with standard values for the best available technology. If the impact of the suggested measures is to be presented, more detailed technical and economical calcu‐ lations are made.

on the type of clamps and loggers available at the moment. In this case we have 500 A, 200 A

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and 20 A current clamp meters.

**Figure 7.** Example of a schematic drawing of an electricity distribution system.

be able to replace the 500 A clamp with a 200 A clamp.

intervals may be enough.

The sampling interval for the current clamps can be changed depending on what we want to know. For the air compressor we may log more frequently, for example every five seconds, if we find that the compressor is switching mode very frequently, otherwise logging at 60-second

The purpose of the continuous measurement will also affect the logging interval. If the first visit gives us the impression that the compressed air system is an important part of the energy use, we may measure more carefully to have enough information to suggest detailed measures. The drawing of the electric distribution tells us that the fuse for the compressor is 250 A, but based on the information from the instantaneous measurements we plan to carry out, we might
