Understanding Scottish Power Economy 7 Bills

MadTogger

Hi,

I have Economy 7 in my house and my electricty supplier is Scottish Power.

I am really trying to understand how my bill is worked out, it all seems to be a bit mystical and secretive. I have contacted Scottish Power but have not really been given any help to understand it.

The night reading side of the bill is straight forward;

kWh used x 4.937p per unit.

The confusion occurs with the day meter reading, the bill shows Primary & Secondary with differing unit prices for each.

Like I said, I contacted Scottish Power for information on how the Primary & Secondary costs are worked out and was emailed back to say that there is an allowance of 225kWh per quarter (900 kWh per year) that is charged on the Primary rate, which is the higher rate of the two, then the rest is charged at the Secondary rate.

e.g.

Primary @ 18.716p per unit
Secondary @ 11.046p per unit

This on the face of it looks very simple to understand, however, when going through my bills I have never been charged the maximum of 225kWh on the Primary rate.
Below are examples from my bills:-

25/07/09 - 13/10/09 : Primary 199, Secondary 610

14/10/09 - 31/12/09 : Primary 194, Secondary 638

01/02/10 - 23/03/10 : Primary 125, Secondary 428

24/03/10 - 14/06/10 : Primary 204, Secondary 687

15/06/10 - 02/09/10 : Primary 197, Secondary 544

As you can see in the last 2 entries of the above data, which do cover a quarter period each, that the max kWh for the Primary is 204 with the Secondary at 687.

Surely if the allowance is 225kWh per quarter on Primary the actual reading should be:-

Primary 225, Secondary 666.

I realise that in doing this my actual bill would increase as the Primary rate per unit cost is higher but the last thing I want is that somewhere down the road an error is found and then I would have to pay a massive amount.

I am an avid budgeter and keep a constant check on every bill.

All I would like is that this peculiar system that Scottish Power uses is explained to me in detail, where I then can come to the same outcome as my bill, not much to ask, is it?

There is one other thing, the Internet Discount.

I get a discount for controlling my bill online, i.e. entering meter readings etc...

There does not seem to be a standard percentage or amount in relation to the bill each time that I can keep track of.

e.g.

£112.22 Bill - £2.19 Discount
£150.55 Bill - £2.27 Discount
£269.74 Bill - £2.19 Discount
£182.08 Bill - £2.21 Discount

as you can see from the above examples, this discount cannot be worked out on a percentage basis as the smallest bill has the same discount as the largest bill.

Any pointers as to how I can glean the info I need would be much appreciated.
I have an A level in Mathematics, yet these utility companies use every possibly way to confuse the end user.
I should be easily able to come to exactly the same figure as Scottish Power but trying to get information from them is like trying to get blood from a stone.

Regards..,

MT

dogshome

Hi MadTogger - They don't make it easy do they

Your 225 Primary units per Quarter is actually based on 900 per calendar year, but because billings are not issued exactly on the years Quarter Days, the Primary Units are charged at a rate of 2.4657534 per day for each day that the bill covers.

Your 15 June to 2 Sept Bill covers 80 days, times this by 2.4657534 gives the 197 Primary Units listed on the Bill
However you are doing exactly the right thing in always checking how many Primes you are being charged for

MadTogger

Hi,

I have finally figured out how this is worked out, no thanks to Scottish Power.

I will layout my workings here, maybe this will help others with this problem.

Firstly the yearly allowance for Primary on the day meter is 900kWh.

So, 900kWh divided by 365.25 (days in a year), gives a figure of:-

2.4640657084188911704312114989733 kWh per day.

Now you need to find the exact number of days of the billing period, I use this website:-

www dot timeanddate dot com slash date slash duration dot html

(sorry I have had to post a link this way, but the forum does not allow new posters to post proper links)

Enter the Start Date & End Date and make sure that the checkbox 'Include end date in calculation (1 day is added)' IS ticked.

Press the 'Calculate duration' button.

The calculation will be done and output as the number of days.

Now multiply the [kWh per day] figure by the number of billing days that you got from the online calc.

The figure you now get is the kWh used on the Primary tariff, (it seems as only the whole number is used, not anything after the decimal point).

Below is an example from one of my own bills;

Billing period: 15/06/10 - 02/09/10 total number of days = 80

80 x 2.4640657084188911704312114989733

= 197.12525667351129363449691991786 round this to 197

So of the total units used on the Day meter, 197 will be charged at Primary tariff.

On this particular bill of mine I had used a total of 741 units on the Day meter, so;

741 minus 197 = 544 (these are the number of units charged at the Secondary tariff).

Hence, my bill shows;

Price Sure - NSC Economy 7 : Day Secondary 544@11.046 £60.09
Price Sure - NSC Economy 7 : Day Primary 197@18.716 £36.87

---

Now the second part of my original post was concerning the Internet Discount figure.

Again, this is actually worked out on a per day basis.

The full yearly discount entitlement is £10, so this figure has to be divided by the number of days in the year just as for the Primary unit allowance.

10 divided by 365.25 = 0.027378507871321013004791238877481

Now, using the number of days in the billing period, same as previously done for the Primary day allowance and staying with my example bill would be;

80 x 0.027378507871321013004791238877481

= 2.1902806297056810403832991101985

or rounding to 2 decimal places = £2.19

This exactly matches my actual bill.

I hope that this helps out anyone else that is trying themselves to keep a tight budget.

Regards..,

MT

MadTogger

dogshome wrote: »

Hi MadTogger - They don't make it easy do they

Your 225 Primary units per Quarter is actually based on 900 per calendar year, but because billings are not issued exactly on the years Quarter Days, the Primary Units are charged at a rate of 2.4657534 per day for each day that the bill covers.

Your 15 June to 2 Sept Bill covers 80 days, times this by 2.4657534 gives the 197 Primary Units listed on the Bill
However you are doing exactly the right thing in always checking how many Primes you are being charged for

Hi dogshome,

thanks for replying, your post came through just as I was posting my follow up, I had just came to the same conclusion and worked it out.

All the best..,

MT

Scottish_Power

Hi MadTogger

If you are looking to budget and double check the bills you are receiving then I agree that the No Standing Charge tariff will make this a little tricky for you. For your information, the No Standing Charge tariff only really benefits customers that are using a very small amount of electricity/gas. Why not have a look at the Standing Charge rates on your current tariff and see what difference there would be in cost. If you find that it is pennies, why not change onto the Standing Charge tariff and make your budgeting much easier as all day units will be charged at a single rate and all night charged at a single rate. Have a look at the link below for the required unit rates:

http://cww.css.scottishpower.plc.uk/css/products/pricing/historic/historic_PriceSure_1st_Feb_2010.pdf

You are able to do this as your current tariff (Price Sure) has the option for both No Standing Charge and Standing Charge. Other tariffs are No Standing Charge only.

Let me know if you have any questions and I will be happy to help.

Kind Regards

Colin @ ScottishPower

MadTogger

scottishpower_company_representative wrote: »

Hi MadTogger

If you are looking to budget and double check the bills you are receiving then I agree that the No Standing Charge tariff will make this a little tricky for you. For your information, the No Standing Charge tariff only really benefits customers that are using a very small amount of electricity/gas. Why not have a look at the Standing Charge rates on your current tariff and see what difference there would be in cost. If you find that it is pennies, why not change onto the Standing Charge tariff and make your budgeting much easier as all day units will be charged at a single rate and all night charged at a single rate. Have a look at the link below for the required unit rates:

..::URL Unavailble::..

You are able to do this as your current tariff (Price Sure) has the option for both No Standing Charge and Standing Charge. Other tariffs are No Standing Charge only.

Let me know if you have any questions and I will be happy to help.

Kind Regards

Colin @ ScottishPower

Hi Colin,

thanks for replying.

By the way, the link you have posted does not work but I did find the PDF on your site.

I have gone through about 1/2 a dozen of my previous bills to see if going down the Standing Charge route would benefit me but unfortunately it averages about £1.20 per quarter more for me to do it that way.

I have got my head round the system now but will still be keeping close tabs on the prices in the future.

Regards..,

MT

MadTogger

MadTogger wrote: »

Hi Colin,

thanks for replying.

By the way, the link you have posted does not work but I did find the PDF on your site.

I have gone through about 1/2 a dozen of my previous bills to see if going down the Standing Charge route would benefit me but unfortunately it averages about £1.20 per quarter more for me to do it that way.

I have got my head round the system now but will still be keeping close tabs on the prices in the future.

Regards..,

MT

Hi Colin,

I have found a tariff that does work out cheaper on average for me;

The Premier Plus Package - Monthly Standing Charge, exactly as I do now.

Apart from the previously stated saving to me, what are the differences between the Premier Plus & the Price Sure tariffs?

Regards..,

MT

Scottish_Power

Hi MT

Your PriceSure tariff is effectively a capped tariff until 31st January 2011. The Premier Plus is our standard monthly Direct Debit rate which is not a capped tariff.

Kind Regards

Colin @ ScottishPower

MadTogger

scottishpower_company_representative wrote: »

Hi MT

Your PriceSure tariff is effectively a capped tariff until 31st January 2011. The Premier Plus is our standard monthly Direct Debit rate which is not a capped tariff.

Kind Regards

Colin @ ScottishPower

Thanks Colin, I will wait until Jan 31st to see then what the price diff will be.

Regards..,

MT