Posted by Craig
Talk to anyone in manufacturing and they will tell you it takes three things to make something: material, labour and machines. This trio is physical – it can be seen, measured, optimised, constrained or replaced.
Anything else is an overhead, something of “infinite” constant quantity: the factory, the compressed air, the heating, the lighting, or the transport.
What they don’t talk about is the physical element that allows manufacturing to take place in the first place: energy. It is needed to complete every process step that will transform the raw materials into a finished product.
The biggest reason why energy is not treated on the same level as material, labour and machines is that it is not “seen” or quantified at a process level. Rather it is “seen” as an input to the entire facility. This is reflected via the monthly or in some cases a quarterly energy bill.
To get more detail as to how much energy is spent when (note not where) utilities provide half-hourly data under the auspices of smart meters as shown in figure 1 – a seven day profile of one of our client’s energy consumption in KWh.
Notice anything unusual with the graph? How about that on most days between the hours of 21h00 to 05h00 there is 100 KWh or so of energy being consumed even though no actual work is taking place in the facility. Or, how about, between days one and two when the consumption went to 150KWh?
So, as an overhead, how does the manufacturer find out where this energy is being consumed? If they treated it like a resource – something that is seen, measured, optimised, constrained or replaced - then they would have a constant Energy Profile on specific groups of machines, factory areas or even individual equipment such as air compressors, chillers, process lines or CNC machines.
Figure 2 shows a detailed granular view of energy consumption. This provides information on not only when the energy is being consumed, but also where it is being consumed.
It allows for a quick and effective way to allocate energy to the manufacturing process that is consuming it. In this case it couldn’t be allocated as it was during non-working hours. Therefore it was wasted resource – a waste running at approximately £24,000 a year!
Treating it as a resource also allows manufacturers to constrain or replace energy consumption. An example is shown in figure 3 – Two similar machines doing the same work over a seven day period. Notice anything unusual? 
Over a 15 year period (the usual life span of these types of machines) the energy consumption difference is large, roughly 10 times as much.
Therefore it makes sense to constrain work of the larger consumer, whenever possible, until the machine can be replaced.This however doesn’t always work. Take a look at figure 4 - another 3 different machines doing similar work at another one of our clients.
This time however the machine using the most energy (the red line) is actually delivering 4 times more finished goods than the one represented by the green line and 12 times more than the one represented by the blue line.
Therefore, in summary, by treating energy as a resource it allows you to become more efficient by being able to see the waste at a detailed level. Being more efficient means that manufacturers have more capacity to do more work and to be more competitive as a by-product it will cost less so increasing margins.
Treat it like an overhead and what you will find is it becomes a cost down exercise where facilities become half lit and energy efficient motors consume energy during non-working hours!Worst of all you may find that the energy overhead is replaced by a renewable energy meaning that traditional generated wasted energy becomes renewable generated wasted energy!
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