Free check · Step 2: Pay less

The Bill Check: ten minutes with your last 12 bills.

Seven checks on your electricity bills, in order, before you spend a rand on new kit. Most sites find at least one charge they control: the tariff, the capacity they book, power factor or the hours they run.

What you need

Your last 12 electricity bills, all pages
The label on your meter panel, for check 5 (your electrician can read it)
Half-hourly meter data if you have it: it helps with checks 3, 6 and 7, but you can start without it

New to the words on a bill? The glossary explains them in plain language.

01 The seven checks

Do them in order, with twelve months of bills.

Check 1
The tariff
Does it still fit how you use power?
Look for
The tariff's name on the bill (Eskom's Megaflex, Miniflex or Nightsave, for example, or your municipality's large-power tariff) and the supply voltage it's charged at.
What it means
A tariff is often chosen once, when the supply is connected, and the site changes after. A time-of-use tariff rewards a site that can run outside the dearest hours; a site that can't may pay less on another. The voltage, and on Eskom the distance from Johannesburg (the transmission zone), change the rates too.
What to do
Price your last 12 months on each tariff your supplier offers you. If one is cheaper, ask your supplier how to change, and how often you may.
Free tool:How much of our bill is peak-hour energy, and what would moving it save?
Check 2
The capacity you book
Is your notified maximum demand (NMD) right for the last 12 months?
Look for
The NMD, or booked capacity, in kVA (on the bill or in your supply agreement), against the highest kVA in each of the last 12 months.
What it means
Most large-power tariffs charge every month for the capacity you booked, used or not, and add a penalty in a month you go over it. Booked far above your highest demand, you pay for capacity you never use. Booked too tight, one busy month costs a penalty.
What to do
If your highest kVA sits well below the NMD, ask your supplier about lowering it, keeping headroom for growth and a bad month. Suppliers limit how often it can change, and raising it again later can cost money and time.
Free tool:Are we paying for capacity we never use?
Check 3
Power factor at the peak
In the month's busiest half-hour, is kW ÷ kVA above about 0.95?
Look for
The maximum demand in kW and in kVA for the same month. Some bills show the power factor itself, or a charge for reactive energy (kvarh) instead.
What it means
Power factor is the share of the current your site draws that does useful work. Below about 0.95, the kVA is higher for the same kW, and kVA is what the demand and capacity charges are billed on. Some tariffs charge for reactive energy beyond a free share instead.
What to do
Below about 0.95, get a capacitor bank sized on your half-hourly data. If you have one, have its steps tested: failed capacitors and blown fuses are common, and the bill shows it only months later.
Free tool:Would a capacitor bank cut our demand charges?
Check 4
The readings
Actual, or estimated?
Look for
An “E”, “Est” or “estimated” next to the meter reading, month by month.
What it means
An estimated month is corrected later, often in one large bill. A run of estimates hides errors and makes the other six checks unreliable.
What to do
Read the meter yourself on the reading date and keep a dated photo. Ask your supplier for actual readings, and check the next actual one against the estimates before you pay the catch-up.
Check 5
The multiplier
Does the bill's multiplier match the CT ratio on the panel?
Look for
The multiplier (or meter constant) on the bill, against the current transformer (CT) ratio on the meter panel's label: 400/5, for example, gives 80. On a medium-voltage supply the voltage transformer ratio multiplies in too.
What it means
A large site's meter measures a small copy of the current, and the bill multiplies each reading back up. A wrong multiplier puts every kWh and kVA on the bill out by the same factor, often from the day a meter or CT was changed.
What to do
Ask your electrician to read the ratio: don't open the panel yourself. If it doesn't match, write to your supplier, ask for a meter audit, and claim back as far as your bills go.
Check 6
The peak share
What share of your kWh falls in peak hours?
Look for
On a time-of-use bill, the kWh in peak, standard and off-peak. Divide the peak kWh by the total, for a winter month and a summer month.
What it means
A peak kWh costs several times an off-peak one, most of all in winter's high-demand season (June to August on Eskom's tariffs). A site with a high peak share pays for when it runs, not only for what it uses.
What to do
List what runs in peak hours that could run at another time: batch work, charging forklifts, pumping to storage, water heating, defrost and cleaning. Each kWh moved saves the gap between the two rates.
Free tool:How much of our bill is peak-hour energy, and what would moving it save?Will a battery pay for itself?
Check 7
The load factor
How steady is your load: average kW ÷ peak kW?
Look for
Divide the month's kWh by the hours in the month to get the average kW, then divide it by the month's maximum demand in kW.
What it means
The lower it is, the more you pay for a short peak you reach only now and then: the demand charges are set by the month's busiest half-hour and spread over fewer kWh, so every kWh costs more.
What to do
Find what sets the peak: usually machines started together at the start of a shift, or compressors loading at once. Stagger the starts and the peak falls, and you may then book less capacity (check 2).
Free tool:How much of our bill is peak-hour energy, and what would moving it save?

Next02Two kinds of saving

02 Two kinds of saving

Some come back every year. Some come back once.

Keep them apart, and never add them together: one is a lower bill for good, the other a refund you have to claim.

Every year

Fixing the power factor, moving work out of peak hours and booking the right capacity save on every bill that follows.

Once

Billing errors (a wrong tariff, a wrong multiplier, estimates never corrected) pay back once, as a refund or a credit, and only if you claim. Look back as far as your bills allow, and claim in writing.

A general check, not advice on a particular bill or supply agreement. Tariffs change every year (Eskom's in April, most municipalities' in July), so check the rates against your supplier's current schedule.

Next03Check the numbers

03 Check the numbers