MOL · capability 04 of 08
Eskom Megaflex has eleven charge components.
Megaflex is Eskom's time-of-use tariff for large customers. A South African utility tariff combines energy charges that change by time of day and season, demand charges with their own reset rules, network and capacity charges, reactive energy penalties and levies, and any of these can change mid-billing-cycle. MOL models all of them, because a bill that is 96 per cent right will be queried.
Roughly 350 tariffs, kept current by a dedicated team.
There are roughly 350 promulgated tariffs in South Africa: Eskom's, plus a set for every Metro, City and Municipality. They change on their own timetables, in their own formats, and not always cleanly.
PMT has a team whose job is to read each NERSA (National Energy Regulator of South Africa) determination and tariff change, and keep the tariff models current. The work is continuous, and it is the reason a MOL bill reconciles with the utility's own invoice rather than approximately matching it.
- Time of use
- Peak, standard and off-peak by season, weekday and public holiday.
- Maximum demand
- Sliding-window and fixed-interval demand, with the correct reset behaviour.
- Inclined block
- Stepped rates where the unit price changes with cumulative consumption.
- Seasonal
- High and low demand season rates, and the changeover mid-cycle.
- Network and levies
- Capacity, network access and ancillary service charges, and reactive energy penalties.
- Summated accounts
- Multiple supply points billed as one, with demand diversified correctly.
Choosing a tariff requires the customer's load profile, not the rate card.
Utilities offer several tariff options, and the cheapest depends on the shape of a customer's consumption as well as the total. A tariff that is cheaper per unit can cost more if the demand peak falls in the wrong half hour.
MOL runs the comparison across twelve months of the customer's actual half-hourly data, so seasonal changes in both consumption and tariff rates are accounted for. Any two tariffs, from any financial periods, can be compared against a load profile from any period.
One worked example
Running the same tariff across two financial periods against a customer's own load profile gives the actual increase for that customer: about 15 per cent in one case, against a stated average increase that was substantially lower.
The stated average is calculated across every customer on the tariff. MOL calculates the increase for the customer's own building. The two figures are rarely the same, and the difference is not visible until the comparison is run.
Cases that break billing systems
A tariff change mid-cycle
The rate changes on 1 July and the billing cycle runs to the 15th. MOL bills each half hour on the tariff in force when it was consumed, rather than a prorated approximation of both.
Demand across summated points
Three intakes can reach their demand peaks at three different times, and adding the peaks overstates the charge. MOL sums the interval data first and takes the demand from the total, as the utility does.
A reading that arrives late
Data recovered after the bill was raised does not silently change the billing history. The adjustment is visible, attributable and traceable to the interval that changed.
Preflight validation
Preflight checks run before every billing run.
A billing run is the last point at which a data problem is inexpensive to correct. After the run, correction requires a credit note, a re-run and a discussion with the customer.
MOL runs a preflight check across the whole billing set first. It covers more than the consumption figures: account, meter point, tariff assignment, meter, phasor and profile, because a wiring fault and a missing interval both result in an incorrect invoice.
Profile checks
- Missing intervals, and zero values during known operating hours
- Readings below the meter's theoretical accuracy limit, or above its theoretical maximum
- Active energy recorded with no corresponding reactive energy
- Quadrant data inconsistent with the installation
- Power factor far enough out to indicate a fault rather than a load
Phasor checks
- Voltage imbalance across the three phases
- Current imbalance beyond what the load explains
- Zero current on a phase that should be carrying load
- Reverse energy on a single phase, which indicates a reversed CT (current transformer)
These checks are part of the billing gate deliberately. A reversed CT is an engineering fault, but it results in a revenue error, and the billing run is where it is caught.
Tenant billing by a reseller is a compliance obligation.
Under the Electricity Act, a reseller must charge tenants as though they were buying directly from the municipality, on the tariff promulgated for that area and without markup.
Tenant billing is therefore a compliance obligation rather than a commercial decision, and the tariff model must be accurate enough to show that each charge is the promulgated one.
See this applied to your own data.
PMT will run it against a month of your readings and show you the results.