Tag: energy management

Path of Resistance

Over the last few months the requirement to reduce our energy consumption at work has increased in the build up to the Carbon Reduction Commitment Energy Efficiency scheme that launches on April 1st.  Whilst I am trying to co-ordinate all the efforts of the group, I am also very aware that as the largest site in the group, I need to try to ensure that we are also making a concerted effort to improve efficiency.

For a bit of background, we are a site that operates 24/7, with two plants running most of the time, depending on customer demand – both do a slightly different job with, in the main, different customers, and are completely different in their mode of operation.  One of these plants and associated peripherals and warehousing space etc is responsible for about 70% of the electricity consumption on site.

Whilst we have started to tackle the lights (more about this in a later post), I think we also need to start looking at the processing equipment itself.  We have had a couple of surveys conducted on site, including one by the Carbon Trust, and both have mentioned the operating pressure of the two compressors that we have.  (We actually have three, but the third is kept as a spare.)  This is where the resistance has started. We have a maintenance team of four, and, unfortunately they have not bought in to the idea of using the CRCEE as a way of making any changes that they would like, and I think this is because they are too comfortable and don’t like the idea of change – I may be doing them a disservice, but I have yet to see any real evidence.

OK, now for a bit more background whilst I explain the issues at hand – sorry if you don’t find compressors overly exciting, feel free to skip to the conclusion.  The compressors are of different types and are both operating all the time (although not on load).  One is a variable speed drive (VSD) compressor which changes its power consumption to match the load, the other is either on or off load.  The VSD compressor has apparently been specified to run both plants if necessary and the pipework is in place to allow us to do that.  This compressor also has a fairly large receiver tank to store the compressed air and smooth out the load.  The compressor kicks in when the pressure in the tank is below 7.5 bar and turns off at 8.5bar (this will become relevant as my story progresses).

So, first question, is the compressor operating in the most efficient way?

Mainenance – it was the most efficient compressor we could get at the time – the suppliers said so.

Me – but, is it running in the most efficient way?  Is it set at the right pressure?

Maintenance – it has always been at that pressure since it was installed.  It is a variable speed drive compressor and the most efficient available at the time.

Me (there is a pattern here) – but can we change the settings so it is operating more efficiently?

Maintenance – it turns off when it hits 9bar and only comes on when it is at 6bar (see, I told you it was relevant).

Herein lies my perennial problem – not only do I not get the answers to the question I asked, but when I do get an answer there is no guarantee that it is the correct answer.  So, my question is, how much time do I spend trying to convince the maintenance team that this is a really good thing, that they don’t have a choice in the long run, that running production equipment inefficiently really is a waste of money and resources, and that they might actually enjoy having some projects out of the ordinary to work on instead of the routine stuff.  The alternative is to go ahead and arrange for some of these things to happen and get them annoyed with me – something I am not afraid to do, but it is hardly conducive to future co-operation, although it would mean we do save energy sooner rather than later.

With regards to the compressor – I have found a solution which I shall tell you about in my next post.

Disclaimer – I am not claiming that all maintenance departments are this obstructive, we have other maintenance personnel within the Company that are leading the way, but I bet there is someone like this in most companies.  Have you encountered similar problems, how did you deal with them?

Lighting in Daventry.

A while ago (as outlined in Lighting – do we have too much?) I started to look at the amount of lighting on our Daventry site.  For various reasons it has taken some time to make any meaningful changes, but at last we are beginning to make some progress.

Surprising discovery number one – we had no light switches for a quarter of our warehouse – even when no one was around we had to leave 3kW of lights on.  Whilst this is only for a small proportion of the year it is still waste.  The lights were controlled by a photocell, unfortunately somewhere along the line a Health & Safety survey had declared that the lighting was insufficient and, instead of changing the levels the detectors were covered up.  This meant that other than tripping the circuit breakers, the lights could not be switched off; even on the brightest of days.

The first step was therefore to sort this ridiculous state of affairs out.  We have now installed some new photocells which can be changed remotely if the initial levels are incorrectly set.  The payback time on this is less than 12 months even if the light is only bright enough to switch them off for 4 hours each day.  The only fly in this ointment is that H&S police have again determined that the light levels initially set were incorrect, and, rather than resetting to the correct levels, they have been turned to permanently on!  A task for the next week will be to sort this problem out.

Other areas have been identified where lights are left on for no reason.  Despite being only a few fluorescent tubes (relatively small in number compared to the aforementioned warehouse) they still represent substantial savings.   The first of these areas was the Plant room – visited only by maintenance staff, and therefore it should have been better controlled.  Unfortunately, unless you are in the room you can’t tell whether the lights have been left on; it was estimated that there were about 158 hours of extra lighting each week in this area.

The second area is a small office in the middle of the warehouse that has no permanent occupant and is subsequently visited by various members of staff, none of whom appears to be capable of turning the light off when they leave.  This 200W of lighting is left on unnecessarily for about 144 hours every week.  The answer to both of these has been the addition of PIRs (Passive Infra Red detectors) – motion detectors.  I think that you can get too carried away with motion detectors and see them as the answer to everything, but in some cases, for example when there are lots of different occupants using a room, only some whom will regularly turn the light off, they can be beneficial.  Both of these projects had estimated payback times of less than 12 months.

The final change that has been made has been a no cost solution and is the most obvious. A member of the maintenance team was asked to survey the lighting of the entire site and, in addition to the number, type and power of the lights, estimate hours of use and the amount of wastage.  As a consequence it occurred to him that one of the areas was visited for approximately 1 hour per week but that all three of the 70W tubes were on permanently.  He was usually the only one to visit the room and has now promised to turn the lights off when the room is not in use, a saving of 1800kWh per year.

Other areas have been singled out as needing a motion detector – these include the toilets, the tea room and the locker room, but I am having less success in getting these fitted – it is starting to become a bit of a mission!

I have now started to look at the rest of the sites within the business unit as part of the requirements for our participation in the Carbon Reduction Commitment Energy Efficiency scheme (CRCEE) and have learnt more about lighting than I ever expected.  Details to follow..

Energy Management – Where does it go and what does it do?

In order to better manage our energy we first need the data to establish our base load; I need to know where the energy is being used.  As a site that uses a substantial amount of energy we pay for our data to be collected every half hour (HHD). Have I been able to get hold of our data?  Yes, but it took me tens of emails, lots of ‘phone calls and three months.  As it stands I am only receiving it monthly, rather than weekly, but it is a starting point.

So, now what?  The data is provided in Excel format and I have been provided with some simple graphing software via the Carbon Trust to illustrate the changes in consumption on an hourly or half hourly basis.  However, I am sure that this is something that I could have done for myself given the data, probably using Excel.

We operate continually with only the occasional shutdown, so finding the base load wasn’t as easy as one would think.  However, I have now estimated that when the site is unoccupied it is still consuming in the region of 860kWh per day.  This is approximately 30% of our total consumption  – at a notional cost of 10p per kWh this would equate to more than £30,000 per year.  Whilst we are only closed for a few days a year, and so not all of this is necessarily wastage, at the moment I have only discovered where 72kWh is used.

My next mission is to discover what is eating the rest of the electricity, whether it is necessary, and to try to pinpoint the costs in the various operations on site.