Energy Glossary

Learn more about Use-of-System (UoS) and other commonly used energy terms.

How is Transmission Loss Factor (TLF) calculated?
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 Singapore.
What is Use-of-System (UoS) Charge?
Contracted Capacity
Peak Period
Off-Peak Period
Reactive Power Charge
Uncontracted Capacity Charge7
Uncontracted Capacity Charge10
Tier 1Tier 2
Ultra High Tension17.
Ultra High Tension27.870.080.030.4811.8139.5539.5594.44
High Tension-Large38.900.740.080.5913.3544.5044.50106.80
High Tension-Small48.900.960.090.5913.3544.5044.50106.80
Low Tension-Large5-5.444.12-----
Low Tension-Small6-5.44-----

1Ultra High Tension - for consumers taking supplies at 230kV, 50Hz, 3-phase, 3-wire for connection with minimum Contracted Capacity of 85,000kW*.

2Extra High Tension - for consumers taking supplies at 66kV, 50Hz, 3-phase, 3-wire for a Contracted Capacity:
a. between 25,501kW and 84,999kW for service connection from the nearest feasible 66kV substation*
b. between 85,000kW and 170,000kW for service connection from the nearest feasible 66kV source station*
The above shall apply to new and existing customers.

3High Tension - Large - for consumers taking supplies at 22kV or 6.6kV, 50Hz, 3-phase, 3-wire for a Contracted Capacity:
a. between 1,700kW and 12,750kW for 1 or 2 HT 22kV services*
b. between 12,751kW and 25,500 for 3 to 4 HT 22kV services*

4High Tension - Small - for consumers taking supplies at 22kV or 6.6kV, 50Hz, 3-phase, 3-wire for connection with Contracted Capacity of less than 1,700kW.

5Low Tension - Large - for consumers taking supplies at 400V/230V.

6Low Tension - Small - for all non-contestable consumers taking supplies at 400V/230V.

7The Uncontracted Capacity Charge (UCC) applies in the event that the maximum demand in kW (measured by the half-hour integration meter) exceeds the Contracted Capacity. UCC applies to:
a. Normal customers without embedded generation;
b. Customers with embedded generation who require top-up supplies and opt to summate their kW output from embedded generation and kW demand from the network (i.e Summation Scheme) for determining maximum demand; and
c. Customers with embedded generation who require top-up supplies and opt to cap their power demand in kW drawn from the network (i.e Capped Capacity Scheme or Extended Capped Capacity Scheme). The UCC applies in the event that the maximum demand in kW (measured by the half-hour integration meter) exceeds the contracted capacity and shall be limited to 20% of the Contracted Capacity.

8For Capped Capacity Scheme (CCS), the Uncontracted Standby Capacity Charge (USCC), at 5 times of Contracted Capacity Charge, applies in the event that the demand in kW (measured by the power meter) drawn from the network exceeds 120% of the contracted capacity for a duration of more than 10 seconds continuously.

9For Extended Capped Capacity Scheme (ECCS), the 2-tier Uncontracted Standby Capacity Charge (USCC) applies as follows:
Tier 1: 5 times of Contracted Capacity Charge is applicable if the demand in kW drawn from the network exceeds 120% and up to 200% of the contracted capacity for a duration of more than 100 seconds continuously.
Tier 2: 12 times of Contracted Capacity Charge is applicable if the demand in kW drawn from the network exceeds 200% of the contracted capacity for a duration of more than 10 seconds continuously.

10For both CCS and ECCS, the consumer shall at its own expense, install and maintain Load Limiting Device, in accordance with requirements that the Transmission Licensee may stipulate from time to time.

*Based on power factor of 0.85
Note: All charges in this Schedule are exclusive of GST.

Common Energy Terms

AFP Charge
This is the charge for the recovery of the cost incurred for the procurement of Regulation. Regulation is energy needed to fine-tune between the generation and consumption of electricity on a half-hourly basis.
Barrel (petroleum)
A volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. gallons (306 pounds of oil, or 5.78 million Btu).
A vessel or tank where heat produced from the combustion of fuels such as natural gas, fuel oil, or coal is used to generate hot water or steam for applications ranging from building space heating to electric power production or industrial process heat.
An electrical device that adjusts the leading current of an applied alternating current to balance the lag of the circuit to provide a high-power factor.
The load that a power generation unit or other electrical apparatus or heating unit is rated by the manufacture to be able to meet or supply.
Circuit Breaker
A device used to interrupt or break an electrical circuit when an overload condition exists; usually installed in the positive circuit; used to protect electrical equipment.
An electric generating technology in which electricity is produced from otherwise lost waste heat exiting from one more gas (combustion) turbines. The exiting heat is routed to a conventional boiler or to a heat recovery steam generator for utilization by a steam turbine in the production of electricity. This process increases the efficiency of the electric generating unit.
The process by which a power plant, apparatus, or building is approved for operation based on observed or measured operation that meets design specifications.
A tubular material used to encase and protect one or more electrical conductors.
The right to choose among electricity retailers for electricity purchase. A contestable customer has the right to choose how and whom they want to buy electricity from.
The rate at which electricity is delivered to or by a system, part of a system, or piece of equipment expressed in kilowatts, kilovolt amperes, or other suitable unit, at a given instant or averaged over a specified period.
Distribution System
That portion of an electricity supply system used to deliver electricity from points on the transmission system to consumers.
The amount of energy service or useful energy delivered per unit of energy input. Often used in reference to lighting systems, where the visible light output of a luminary is relative to power input; expressed in lumens per Watt; the higher the efficacy value, the higher the energy efficiency.
EMC Admin Charge
EMC (Energy Market Company) operates the wholesale electricity market. EMC runs the electricity pool and manages the energy settlement processes. This is a usage-based charge calculated using loss adjusted data.
Energy Audit
A programme whereby an energy auditor or energy auditing company inspects a facility or premise to assess the energy use and suggest ways of saving energy.
Energy Market Authority (EMA)
The regulator of the electricity and gas industry in Singapore.
Energy Market Company (EMC)
The company that operates and administers the wholesale electricity market.
A power line for supplying electricity within a specified area.
A safety device consisting of a short length of relatively fine wire, mounted in a holder or contained in a cartridge and connected as part of an electrical circuit. If the circuit source current exceeds a predetermined value, the fuse wire melts (i.e. the fuse 'blows') breaking the circuit and preventing damage to the circuit protected by the fuse.
Gigawatt (GW)
A unit of power equal to 1 billion Watts; 1 million kilowatts, or 1,000 megawatts.
A system of interconnected power lines that transport electricity from generators to consumers.
Installed Capacity
The total capacity of electrical generation devices in a power station or system.
A device or material with a high resistance to electricity flow.
The amount of electrical power required by a consumer.
Load Factor
The ratio of average energy demand (load) to maximum demand (peak load) during a specific period.
Load Profile or Shape
A curve on a chart showing power (kW) supplied (on the horizontal axis) plotted against time of occurrence (on the vertical axis) to illustrate the variance in a load in a specified time period.
Market Support Services (MSS)
These are services such as the buying of electricity indirectly from the wholesale electricity market for contestable consumers at spot prices, reading meters, managing meter data, administering transfer processes, and providing electricity to non-contestable consumers at regulated tariffs.
Market Support Services (MSS) Charges
Charges to cover the costs of market support services, such as transfer processing fees, meter reading fees, etc.
Market Support Services Licensee (MSSL)
The company that is licensed to provide market support services SP Services Ltd is the MSSL.
Natural Gas
A hydrocarbon gas obtained from underground sources, often in association with petroleum and coal deposits. It generally contains a high percentage of methane, varying amounts of ethane, and inert gases; used as a heating fuel.
Non-Contestable Consumers
Consumers who are required to buy electricity from the MSSL at regulated tariffs.
Off-Peak Period and Peak Period
The period of time when there is relatively low demand for electricity (off-peak), as opposed to the period of time when there is maximum demand for electricity (peak).
PSO Admin Charge
PSO (Power System Operator) is responsible for the security and reliability of the transmission system. All customers pay a usage-based fee for the provision of this service.
The statutory body that regulates the electricity industry in Singapore. The Energy Market Authority is the regulator.
Renewable Energy
Energy derived from resources that are regenerative or for all practical purposes cannot be depleted. Types of renewable energy resources include moving water (hydro, tidal and wave power), thermal gradients in ocean water, biomass, geothermal energy, solar energy, and wind energy.
Short Circuit
An electric current taking a shorter or different path than intended.
An electrical installation containing power conversion (and sometimes generation) equipment, such as transformers, compensators, and circuit breakers.
An electromagnetic device that changes the voltage of alternating current electricity. It consists of an induction coil having a primary and secondary winding and a closed iron core.
Transmission Charges
The charges for the use of the transmission system to deliver electricity to consumers’ premises. Transmission charges are regulated by the regulator.
Transmission and Distribution Losses
The losses that result from inherent resistance in electrical conductors and transformation inefficiencies in distribution transformers in a transmission and distribution network.
Vesting Contracts
Bilateral contracts between generation companies and MSSL for the production and sale of a specified quantity of electricity at a specified price (known as the “vesting price”). Vesting contracts are imposed by the regulator to curb market power of generation companies.
Vesting Debit/Credit
Reflected in MSSL’s bill to contestable consumers buying electricity from the wholesale market through MSSL. It is the difference between spot prices and vesting price on the demand that is covered by vesting contract.
Wholesale Electricity Market
An electricity market where generation companies compete to sell electricity.
Wholesale Electricity Price (WEP)
When buying electricity directly or indirectly from the National Electricity Market of Singapore (NEMS), one’s electricity price comprises of 6 components with USEP being by far the largest of the 6 components. The other components are the Hourly Energy Uplift Charge (HEUC), the Monthly Energy Uplift Charge (MEUC), the Allocated Regulation Price (AFP), PSO admin fees and EMC admin fees.