TARIFF
The electrical energy
produced at the generating station is delivered to a large number of consumers.
The rate at which energy is sold to the consumers (called tariff) is fixed by
the supplying company .While fixing the tariff, the supply companies are to ensure
that they should not only recover the total cost of producing the energy but
also earn some profit. However, the profit should be minimum possible so that
electrical energy can be sold at reasonable rates and the consumers insured to
use more electricity.
IMPORTANT TERMS
·
Connected load : The sum of the
continuous ratings of all the equipments connected to the power system is
called connected load.
· Maximum
Demand :
The load on
the power station is not constant, it varies from time to time.The greatest of
all the demands (loads) which occur during a given period is called maximum
demands.
· The
ratio of maximum demand on the system to the rated connected load to the system
is called demand factor.
Mathematically ,Demand factor = Maximum
demand
Connected load
The
actual maximum demand is always less than the rated load connected to the
system , therefore, demand factor is always less than unity.
The
rate of electrical energy at which it is sold to the consumers is called tariff
.The supply companies invest money to generate, transmit and distribution of
electrical energy, a tariff is fixed .The cost of generation depends upon the
magnitude of energy consumed by the consumers and his load conditions.
Therefore, due consideration is given to different types of consumers (e.g.
domestic, commercial and industrial) while fixing a tariff
The main objective of the tariff is to ensure the
recovery of the total cost of generation and distribution .Tariff should
include the following items:
(1) Recovery of cost of electrical energy generated
at the generating system.
(2) Recovery of cost on the capital investment in
transmission and distribution system.
(3) Recovery of cost of operation, supplies and
maintenance of equipment.
(4) Recovery of cost of metering equipment, billing
and miscellaneous services .
(5) A marginal return (Profit) on the capital
investment
TYPES OF TARIFF
There are various types of consumers ( domestic,
commercial and industrial etc.) and their energy requirements are also
different. Accordingly, several types of tariffs have been designed so far, out
of which the most commonly applied are described below:
1. SIMPLE
TARIFF
2. FLAT
RATE TARRIF
3. BLOCK
RATE TARIFF
4. TWO-PART
TARIFF
5. MAXIMUM
DEMAND TARIFF
6. POWER
FACTOR TARIFF
1.Simple
Tariff: The tariff in which the rate per unit of energy is
fixed, is called simple tariff.
This
is a simplest possible tariff. The rate per unit of energy consumed by the
consumer is fixed irrespective to the quantity of energy consumed by a
consumer. This energy consumed is measured by installing an energy meter
The
following are the advantages :
1.
It is in simplest form and easily understood by the consumers.
2. Consumer
is to pay as per his consumption.
Disadvantages
1.
Consumer is to pay the same rate per
unit of energy consumed irrespective of the number of units consumed by him.
Hence, consumers are not encourage to consume more energy.
2.
The cost of energy per unit delivered is
high.
3.
The supplier does not get any return for
the connection given to the consumer if consumer does not consume any energy in
a particular month.
Application :
Since
it is very simple form of tariff, it is generally applied to tube wells which
are operated for irrigation purposes
2.
Flat rate tariff.
The tariff in which different types of consumers are charged at
different per unit rates is called flat rate tariff. This type of tariff
is similar to simple tariff. Only difference is that consumers are grouped into
different classes and each class of consumer is charged at a different per unit
rate. For example flat rate for fan and light loads is slightly higher than
that for power loads.
Advantages
(1) It is fairer to
different types of consumers.
( 2) It is quite simple
in calculations.
Disadvantages
(1) Consumers are not
encouraged to consume more energy because same rate per unit of energy consumed
is charged irrespective of the quantity of energy consumed.
(2) Separate meters are
required to measured energy consumed for light loads and power loads.
(3) The suppliers does
not get any return for the connection given to the consumer if he does not
consume any energy in a particular period or month.
Application :Generally
applied to domestic consumers. Since it is simple and easy for explanation to consumers, therefore this tariff is
3.block rate tariff:
The
tariff in which first block of energy is charged at a given rate and the
succeeding blocks of energy are charged at progressively reduced rates is
called block rate tariff
In this type of tariff,
the energy units are divided into numbers of blocks and the rate per unit of
energy is fixed for each block. The rate per unit of energy for the first block
is the highest and reduces progressively
with the succeeding blocks. For example, the first 100 units may be charged at
the rate of Rs. 3.00 per unit; the next 100 units may be charged at the rate of Rs.2.50 per unit
and the remaining additional units may charged at the rate of Rs. 2.00 per unit.
Advantages:
(1)
By giving an incentive, the consumers
are encouraged to consume more energy. This increases the load factor of the
power system and hence reduces per unit cost of generation.
(2)
Only one energy meter is required to measure
the energy .
Disadvantages:
(1)
The supplier does not get any return for
the connection given to the consumer if consumer does not consume any energy in
a particular period.
Application
This type of tariff is
mostly applied to domestic and small commercial consumers.
4.Two – Part Tariff
The tariff in which
electrical energy is charged on the
basis of maximum demand of the consumer and the units consumed by him is called
two- part tariff.
In this tariff, the
total charges to be made from the consumer are split into two components namely
fixed charges and running charges. The
fixed charges are independent of energy consumed by the consumer but depend upon the maximum
demand, whereas the running charges depend upon the energy consumed by the
consumer. The maximum demand of the consumer is assessed on the basis of the kW
capacity of all the electrical devices owned by a particular consumer or on the
connected load
Thus, the consumer is
charged at a certain amount per kW of energy is consumed i.e.
Total charges= Rs. (a X kW + b X kWh )
where, Rs. a= charges
per kW of maximum demand
Rs. b= charges per kWh of energy
consumed
In this tariff
basically, the charges made on maximum demand recovers the fixed charges of
generation such as interest and depreciation on the capital cost of building
and equipment, taxes and a part of operating cost which is independent of
energy generated. Whereas, the charges made on energy consumed, recovers
operating cost which varies with variation in generated (or supplied) energy.
Advantages
(1)
It is easily understood by the
consumers.
(2)
The supplier gets the return in the form
of fixed charges for the connection given to the consumer even if he does not
consume any energy in a particular period.
Disadvantages
(1)
If a consumer does not consume any
energy in a month even then he has to pay the fixed charges .
(2)
Since the maximum demand of consumer is
not measured, therefore, there is always conflict between consumer and the
supplier to assess the maximum demand.
