Tuesday, December 29, 2015


What is MD?

MD is measured in Kilowatt (kW). It is the highest level of electrical demand monitored in a particular period usually for a month period. Maximum Demand for any month shall be deemed to be twice the largest number of kilowatt-hours (kWh) supplied during any consecutive thirty minutes in that month.​

Why does TNB charge MD?

 MD is the peak load imposed by the customer to TNB system at any point of time. TNB need to cater for this peak load whenever required by the customer. Since electricity cannot be stored there must be sufficient available generation, transmission and distribution capacity to meet the highest demand. MD tariffs are structured to reflect the time of day it is used. For these reasons most tariffs for larger users are designed to encourage customers to control their electricity demand at daytime peaks. For example, lower night rate electricity encourages the transfer of daytime usage to the night period. The MD charge is being practiced by almost all utilities in the world.

How do you calculate MD charge?

MD is the highest level of electricity demand recorded by TNB meter during a 30-minute interval in a month. The amount charged to customer is based on the recorded MD in kW multiplied by the respective MD rate. For example, the amount payable by a Tariff C2 customer registering 100kW of MD for a particular month is RM3608 (80kW x RM45.10/kW)

 The highest demand recorded by TNB for the month.

Steps to reduce MD charges?

Few activities could be carried out by customers that assist in reducing MD charges such as:
  • Practicing demand side management such as peak shift i.e. shifting their peak operation/consumption to off peak period as MD charges is not applicable during off-peak period for customer with peak/off-peak tariff
  • Opting for any promotional scheme offered by TNB relating to MD such as Sunday Tariff Rider Scheme (STR).
  • Starts your motor/equipment in stages or during off-peak period

Here are some quick facts about Maximum Demand (MD), as billed by Tenaga Nasional Berhad:

  • Maximum Demand is applicable for TNB Consumers in tariff C1, C2, E1, E1S, E2, E2S, E3, E3S, and F.
  • Maximum Demand is not charged for household (Tariff A) and Commercial under Tariff B.
  • Maximum Demand is only calculated during peak hours, from 0800 hrs till 2200 hrs.
  • Unless you have a special Sunday Tariff Rider (STR) from TNB, MD is calculated for every day of the week.
  • For those with STR, Maximum Demand is not calculated on Sundays.
  • Demand is the rate of energy used and it is measured in kilowatts (kW). This is not to be confused with energy which is measured in kilowatts-hour (kWh).
  • Demand is calculated on fix half-hour (30 minutes) periods. For each day, the first 30-minute period starts at 0800 till 0830 hours. Then, the next 30-minute period is from 0830hrs till 0900 hrs, and so forth - right up to 2200hrs.
  • TNB calculates the half-an-hourly demand based on energy consumed during that period. For example, if 2000kWh of energy is consumed from 0800 till 0830 hrs, the demand would be (2000 divided by half-hour) 4000kW.
  • At the end of the month, TNB records the highest (hence the name Maximum) demand calculated for all the half-hour periods in the month.
  • The consumer is then billed based on the recorded Maximum Demand 

No comments: