Reactive power charges....

[Darkwood]

Just had a phone call from a potential new customer who says the energy supplier has called him and told him they are now going to add a extra charge for reactive power to his bill... now im aware of the corrective measures needed but not known of this charge been implemented before... have you seen this charge yourself implemented with your customers who may have a poor PF value.

 

[plugsandsparks]

Are they just going to change his meter to KVA ?

 

[Darkwood]

Hes already got polyphase smart meter that measures all the values they just decided to add the charges from now on but first time ive come across this, they said they have absorbed the costs themselves but now are going to ask for a charge... im wondering if there is a threshold at which charging is triggered or is this a new trend ?

 

[Bobster]

I know on site we have to keep ours above 0.87 otherwise we have a surcharge to pay. Although we often off set that by allowing certain parts of the plant to be shut down when the DNO network is struggling.

I take it this is a commercial/industrial set up?

 

[Darkwood]

Yep full of inductive loads and 10 x 30+kw motors on VSD's so dread to think what PF is just supprised on the charge as ive not come across it before.

 

[Bobster]

Pf might not be as bad as you think. Are all the drives fed from the same mcc board? Wouldn't be that big a job to fit a local active power cap unit. Although it might be worth while seeing what the charges are compared to the price of a cap bank. I know a couple of our smaller satellite sites (from the sound of it a similar size to the one your looking at) just pay the charges as a cap bank wouldn't pay itself back fast enough.

 

[Darkwood]

Its about £1500 yr and now several machines different lines etc so one large cap bank upstream best in this case... as i said im fine with the cure just a thread regarding the charge itself as first time in 25yrs ive heard it been implied.

 

[Bobster]

I'll enquire tomorrow for you, I've never looked into what the parameters are for being charged. I let the bloke higher than me deal with the Dno.

 

[Marvo]

You'll probably need to speak to the DNO or energy resaler about their policies. It's not uncommon especially in large commercial and industrial for punitive charges to be levied if their pf is below a certain threshold. We've come across this when working in a couple of EU countries so I doubt the UK would be any different. The charges are usually sufficient to make it worthwhile in the long term to install corrective measures.

 

[Marvo]

Hes already got polyphase smart meter that measures all the values they just decided to add the charges from now on

I was actually going to suggest you run a power analyzer on site for a few days but if they've got a smart meter yu should be able to harvest the info you need from there. Take an optical-USB cable to site and take a memory dump from the meter. It should be in orbis compliant format, if you want to graph it for easier analysis give me a shout and I'll e-mail you an excel spreadsheet I built for a similar purpose, with a few tweaks it should throw up graphs for most metering devices.

 

[plugsandsparks]

I have not heard of this unless the customer is changing their requirements from DNO, i.e. upping their supply but funny how they already have a measuring device (smart meter) to tell the DNO how much the PF is affecting their supply, perhaps a sign of things to come.
Several of my clients also have smart meter and is paying for KW/h a couple have no PF correction. Will keep an eye out.

 

[Bobster]

Well after speaking to the sites Dno this morning, the best information I could get from 'Dave' on the phone was they assess each site individually, which to be honest I think is a load of bollox and was just a quick way of shutting me up on the phone.

 

[Darkwood]

I can sort of see the case for individual assessment as it depends on the spare capacity of the sub station for other users... if you are putting reactive power into the system it can limit spare capacity and they can't utilise it and sell it but im wondering if this is going to roll out into a money grabbing scheme as admittedly explaining reactive power isn't easy even when you know what it is.

 

[Engineer54]

I haven't seen any large commercial, or any half decent industrial sized installations without capacitor banks being fitted at it's switchboards, normally at the insistence of the supply companies!! So i'd say it's very common, especially where a number of large motors or other extensive reactive loads are concerned!!

 

[Gavin A]

Does anyone have examples of the sorts of charges being made for these PF issues?

I've been talking with the solar inverter manufacturer SMA, and found out that their inverters have the ability to assist with PF correction, though it's so far not been used in the UK.

If anyone has these issues on a site ideally in the Northern Power Grid area, which has a decent size southish facing roof and fancies trialling this technology, we've got agreement with SMA to support us on setting up the inverters correctly to achieve this and would love to work with anyone on a couple of monitored case study situations.

Assuming the site would have to be a high day time energy user to be causing PF issues, the costs and paybacks from 50-250kWp solar installations are only in the 5 year region now, and potentially lower if the PF charges are significant and we actually were able to sort that issue out via the solar inverters... and the up front costs are a hell of a lot lower than a couple of years ago.

Just a thought anyway.