#1 Aug. 10, 2013 10:16:00

avalanche
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Voltage Stabilisation-A new beginning?


Jamie,


Back in 2011/ 2012 there was a discussion on the forum regarding what was then termed “Voltage Optimisation”, although to avoid confusion with “Panel Optimisation” I prefer to call it “Voltage Stabilisation”. It referred to a devise that reduced the incoming voltage to a nominal 220V where users were commonly experiencing higher AC voltages.


The claim is that significant cost savings would be accrued due to the fact that the user would draw less electricity from the grid, thereby saving money.


One of the original links to this discussion is below:


Previous Voltage Stabilisation


At the time I had severe reservations about the effectiveness of this type of equipment and identified some, what I saw to be, significant downsides. I still have those concerns, but am increasingly coming across people who are being “encouraged” to take up this technology.


And so, now that we are more than 12 months on, and the fact that we now have upward of 6100 contributors to the database (we only had a few hundred back then), I would like to open the discussion again to:


1. What your opinion/ research/ experience/ recommendation is on this type of technology? Is it effective in a domestic scenario?


2. Canvas opinion across the forum on personal experience gained for those that have it.


3. Conclude, as best we can, if this technology is now an effective proposition.


Of course, clearly associating a 10% cost saving as a specific result of using this equipment, outside of a controlled expeiment, would be extremely difficult to do, hence my request of Sheffield.


Originally, this technology was selling for around £600. It is now reducing over time and, as such, may become a serious choice for some people if it is proven an effective and valued addition to a renewably-centric houshold.


For those unfamiliar with what the equipment is and does, here is an example being offered:


Example Voltage Stabiliser


Best Regards,





Avalanche








Edited avalanche (Aug. 10, 2013 10:16:00)

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#2 Aug. 12, 2013 14:15:00

SteveRogers
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Voltage Stabilisation-A new beginning?


I've just had a thought about the combination of many inverters and voltage optimisation.


A lot of inverters these days have a maximum AC output of 16A and, theoretically, it is necessary to apply for permission to your regional distribution company to exceed this.  My own SMA 3600TL is a typical case.


Now, remember that  watts = amps x volts


So, if you limit the voltage to 220V (through voltage stabilisation) and your current output is limited by your inverter to 16A then, presumably, the instantaneous AC watts put out by your PV system will be capped at 3520.


This is considerably lower than the 3680 watts that I typically see on a sunny day (sometimes this is even a bit higher which might reflect an increased mains voltage).  The effect would be to reduce the PV output on a sunny day by maybe up to 1 kWh.


I may have misunderstood or missed something critical but I would not want my PV system output to be capped in this way.


Steve








Edited SteveRogers (Aug. 12, 2013 14:15:00)

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#3 Aug. 12, 2013 20:17:00

avalanche
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Voltage Stabilisation-A new beginning?


Steve, 


Yes, agree.  In fact, you’ve erred on the conservative side,  it would probably work out just over a kWh.  If we receive enough feedback on this topic I’ll collate the responses into a table and place in one post so that all have visibility. 


Simply measuring a reduction through the meter is not hard enough evidence that voltage stabilisation generates as positive a saving as is claimed as there are far too many other variables to consider.  


However, I am interested in the technical effectiveness of this technology as a principle.


As a matter of interest I asked the supplier I referred to for another quote: 


£599 inc VAT plus approx £100 installation fee, £700 total.  So this supplier hasn’t raised his prices, but hasn’t lowered them either! 


They guarantee a 10% reduction in annual consumption.  Assuming an annual consumption of 4000kWh.    400kWh (reduction) @ 12.78p/kWh  = £51.12 


Payback = £700/£51.12 = 13 year payback. 


To make the 5 year payback claimed by the supplier you would have to save £140/ year , which equates to over 1000kWh reduction in the first year.  If my maths is correct (it may not be, please check!). 


It may be possible, if you live alone and own a ranch.  


Regards, 


Avalanche 








Edited avalanche (Aug. 12, 2013 20:17:00)

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#4 Aug. 13, 2013 13:47:00

Jamie
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Voltage Stabilisation-A new beginning?


Hi all,


This isn't a concept i'm overly familiar with, having completed a (mostly theoretical) Physics degree… I've done a little reading on the topic and the consensus from everyone other than the companies selling the products seems to be that many appliances, though they run perfectly well at 220V, rarely offer much, if anything, in the way of savings. (e.g. anything involving heating or cooling).


I've also heard that voltage optimisation/stabilisation can have a detrimental effect on neighbours by increasing their average voltage, though i've not found any evidence to support this during my brief search of the web. This would then disrupt the efforts of the national grid (albeit in a very small way) to achieve voltage harmonisation across the network.


report published on the ofgem website (on a trial carried out on behalf of vphase and SSE) reckons the saving for non-electrically-heated homes could be 6.3%.


Some links:


YouGen Blog


University of Nottingham Voltage Optimisation Guide


Regards


Jamie











Jamie Taylor (Sheffield Solar Team)

Edited Jamie (Aug. 13, 2013 13:47:00)

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#5 Aug. 13, 2013 20:33:00

avalanche
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Voltage Stabilisation-A new beginning?


Jamie,


Thanks for the valuable input. Takes a balanced view of it. Nottingham's report is interesting and I've emailed them for further information.


Also found this “Which?” report tonight.


Which? Report


We're getting some good feedback, a picture is beginning to emerge.


Regards,


Avalanche








Edited avalanche (Aug. 13, 2013 20:33:00)

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#6 Aug. 15, 2013 20:51:00

avalanche
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Voltage Stabilisation-A new beginning?


Hello to all, 


If you’ve read the Nottingham University article, you may be interested in their opinion of use in a domestic scenario.  I summarised the points others had made into a single email to them.  I have included both to enable you to correlate questions and answers.  I have had to post in two separate entries due to cut and pasting errors.  Their response is measured and balanced: 


Hello,

We are currently running a debate on the benefits and downside of using 
a voltage stabilisation system in a domestic environment, in particular 
in association with a PV system. Your article “Voltage Optimisation” 
appears to relate specifically to industrial applications. Could you 
advise if there are any downsides to using such a device in a domestic 
situation?

Such downsides already considered include:-

1. Wired in series- does not incorporate a bypass. Therefore, in event 
of unit failure loss of all AC supply results.

2. With PV system would artificially “cap” the potential output of the 
inverter AC output (P=VI)

3. At a cost of £700 to purchase and install - payback = 13 years plus 
(at current unit cost and kW unit cost).

4. With domestic current ceiling at 16 amps, with a PV system generating 
at 3680 watts the current drawn equates to 16.73 amps @220V and 
15.33amps @ 240V. If the PV system exceeds a drawn current 
above the 16 amp threshold authorisation from the DNO must be sought. 
That's why most installers fit 3.6 kW inverters over 4kW inverters..

5. With stabilisation set at the lowest limit of 220V, when voltage 
fluctuations are taken into account, increased in failure rate can occur.

6. Savings of £40/annum (assumed annual consumption of 4mWh @ 
12.78p/unit @ 8% proposed annual saving) can easily be achieved through 
changes in behaviour alone and/or switching to LED lighting (cheaper)

We would be interested to hear your considered opinion on domestic use 
as more and more people (especially those purchasing PV systems) are 
being “encouraged” to take up this technology.

many thanks

Best regards,







Edited avalanche (Aug. 15, 2013 20:51:00)

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#7 Aug. 15, 2013 21:03:00

avalanche
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Voltage Stabilisation-A new beginning?


“Good morning



Thank you for the enquiry and you do raise a valid point (or two).



As you have already identified we have concentrated on the commercial and industrial applications where we have seen merit in installing a Voltage Optimisation device.
They can provide savings (depending on the overall type of load) and with some devices improve conditions such as load distribution over 3 phase installations. Also due to a reduction in pressure (Voltage is a pressure) most equipment when the Voltage is optimised or reduced, in nearly all cases, prolongs the life expectancy of equipment.

In the case of a domestic or single phase installation one must consider the effort (physical and financial) of purchasing and installing such a device when the opportunities to save energy sustainably are limited.

I do not know if you have tested or considered more than one manufacturer's device but you will get a different result depending on the design, capacity, capabilities (features) and of course cost.

As we have not researched any domestic models we cannot comment on item 1. Of your list however with a commercial/industrial version this is taken into account. This could be achieve on a domestic version fairly simply using a No-Volt release mechanism to actuate a bypass. If this is not already incorporated into the device then this will of course add to the costs of installation and therefore affect the payback on the investment.

On item 2. I don't feel I could comment as I don't have sufficient information to assess this.



Item 3. Seems obvious. Your assumption/calculated payback isn't very attractive however I would just like to comment that this could be reduced taking into account the prolonged life expectancy of some equipment over this period and beyond.

I note your comments in 4.



Item 5. As I stated earlier we have no experience in domestic or single phase devices. Yes if the device is simple ie it is basically a stepped-down Voltage resulting then this could have a negative effect on the something on the circuits. Much equipment that we have in our homes will happily run at Voltages less than 220Volts so the cases where a negative effect occur will be small. Many commercial/industrial devices maintain a set Voltage level independent of the fluctuations of incoming supply Voltage.



Item 6. Seems to hit the nail on the head, there are many measures that can be taken in a home (with the exception of trying to educate some teenagers) through behaviour changes, having smarter controls on devices which switch on and off at certain times, reduction in thermostat settings (even on a gas or oil system, this reduces the duration of pumps etc running) and as you have already identified changes in the types of lighting used.

I have done a quick desktop search of information from suppliers of both PV and Optimisers and the consensus is that they can both work well together but I am only relaying what I found during this brief search.

I also came across this http://www.microgen-database.org.uk/forums/general-discussion/voltage-optimisationwhich has some interesting comments on it many in line with your own in particular
I am not sure I have been particularly helpful.



Regards”





Edited avalanche (Aug. 15, 2013 21:03:00)

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#8 Aug. 17, 2013 13:41:00

SteveRogers
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Voltage Stabilisation-A new beginning?


Nicely summarised, Avalanche.  I won't be investing in Voltage Stabilisation anytime soon


I think we can discount the suppliers' concensus that PV and Voltage Optimisation work well together if they are selling both systems!


Steve





Edited SteveRogers (Aug. 17, 2013 13:41:00)

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#9 Aug. 17, 2013 21:15:00

avalanche
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Voltage Stabilisation-A new beginning?


Steve,


 The first line of the post date / time stamped “15/08/2013  21:03”  I appear to have missed off which will lead to a degree of confusion, perhaps.  


To be clear, that post is the response from Nottingham University to my query to them in the post date / time stamped 15/08/2013 20:51 above it. 


Interesting isn’t it! 


I’ll tabulate a full comparison soon.  


Regards, 


Avalanche 








Edited avalanche (Aug. 17, 2013 21:15:00)

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#10 Aug. 18, 2013 10:02:00

rogerhoward
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Voltage Stabilisation-A new beginning?


Well done Avalanche for this really great thread, which is truly worthy of the electricians forum.


It's about time that the exaggerated claims for the domestic energy savings of these things were debunked a bit.


My local authority has unfortunately wasted part of an EU fund for carbon reduction on fitting them to over 40 council properties, when the money could have been used for water softeners, etc to some real benefit. This was on the advice of their well-respected partnering Energy Consultants (who presumably were paid a decent a chunk of the EU grant too).







Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

Edited rogerhoward (Aug. 18, 2013 10:02:00)

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