Change in Transmission Loss Factor
April 2011

Current TLF (as at April 2011)
The table below (source: SP Services Ltd website) shows the new TLFs that apply from 1 Apr 10 onwards till revised by the Market Support Services Licensee, SP Services Ltd, in accordance with the methodology approved by the Energy Market Authority of Singapore.
Load
Transmission Loss Factors effective 1 April 2010
Transmission Loss Factors effective 1 April 2011
230kV/400kV
1.0
1.0
66kV
1.0
1.0
22kV
1.005652
1.001970
6.6kV
1.020237
1.009234
230/400V
1.042518
1.023248


About TLF
The Transmission Loss Factor (TLF) is calculated by the Market Support Services Licensee, SP Services Ltd in accordance with the methodology approved by the regulator, the Energy Market Authority of Singapore1.

In practice, it varies depending on the voltage level at which a consumer takes its electricity supply. The higher the voltage level, the lower the TLF. The metered quantity of electricity generated by generating units is less than the metered quantity of electricity consumed due to transmission losses (energy loss as heat as electric current passes through the transmission system (comprising the transmission network and distribution network)) as well as unaccounted for energy2. 

The TLF is used to allocate the difference to consumers based on their deemed contribution to this difference (mainly transmission losses for Singapore, unaccounted for energy can be greater than transmission losses in a few other countries due to rampant electricity theft). The lower the voltage level of electricity consumption, the more transmission losses are incurred delivering electricity from where it is generated to where it is consumed. This explains why TLF is higher for electricity consumption at lower voltage levels.


How Changes in TLF Impacts a Seraya Energy Customer
For Seraya Energy’s electricity customers, a change in the TLF which in practice applies from 1 April of every year may or may not impact their electricity bills. It depends on the contract terms which may be loss-adjusted or metered. Loss-adjusted means that the metered electricity quantity is multiplied by the relevant TLF to obtain the deemed electricity quantity consumed. Therefore loss-adjusted customers are affected by changes in the TLF.

For metered customers, the metered electricity quantity is not multiplied by the relevant TLF to obtain the deemed electricity quantity consumed. Therefore, metered customers are not affected by the changes in the TLF. Consumers who buy electricity through regulated tariffs (non-contestable consumers) or through the Market Support Services Licensee, SP Services Ltd are all subject to changes in the TLF.

 As metered customers do not have their metered electricity consumption scaled up by the TLF, they have an implicit discount vis-à-vis loss-adjusted customers paying the same electricity price.  Pricing and discounts are therefore naturally different for loss-adjusted versus metered customers.

1 See section 6.1.4 of the Market Support Services Code (available for download at here)for more details.

2 A catch-all to classify the residual difference not accounted for by transmission losses. It includes under-metering of electricity consumption which can be due to various reasons and accounts for the fact that the estimation of transmission losses is not an exact science.