Electrical Energy Management: Conservation Methods | 10th Science

Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail for 10th Science : Chapter 22 : Environmental Management : Electrical Energy Management

Electrical Energy Management

Electrical Energy Management

Electricity or electric power is produced by generators. The generators are operated by the turbines attached to it. The turbines are rotated by steam, moving water or wind power to produce electricity.

Conservation of electrical energy

The following measures can be taken even at home and school to save electricity

• Use energy efficient appliances to save electricity like Compact Fluorescent Lamps (CFL), Light Emiting Diode (LED) bulbs and other electric equipments.
• Switch off the lights and fans, television and other electrical appliances when not in use.
• Switch of the mobile phone chargers when not in use.
• Maximise the use of solar radiation. Solar water heating system can be used instead of electric geysers.
• Minimise the use of air conditioners.

Electric Power: Definition, Formula, SI Unit, and Energy Consumption Explained

Electric Power - Definition, Formula, Unit, Consumption

ELECTRIC POWER

In general, power is defined as the rate of doing work or rate of spending energy. Similarly, the electric power is defined as the rate of consumption of electrical energy. It represents the rate at which the electrical energy is converted into some other form of energy.

Suppose a current ‘I’ flows through a conductor of resistance ‘R’ for a time ‘t’, then the potential difference across the two ends of the conductor is ‘V’. The work done ‘W’ to move the charge across the ends of the conductor is given by the equation (4.19) as follows:

$$ W = VIt $$

$$ P = \frac{\text{Work}}{\text{Time}} = \frac{VIt}{t} $$

$$ P = V I \quad (4.21) $$

Thus, the electric power is the product of the electric current and the potential difference due to which the current passes in a circuit.

1. Unit of Electric Power

The SI unit of electric power is watt. When a current of 1 ampere passes across the ends of a conductor, which is at a potential difference of 1 volt, then the electric power is

\( P = 1 \text{ volt} \times 1 \text{ ampere} = 1 \text{ watt} \)

Thus, one watt is the power consumed when an electric device is operated at a potential difference of one volt and it carries a current of one ampere. A larger unit of power, which is more commonly used is kilowatt.

2. Consumption of electrical energy

Electricity is consumed both in houses and industries. Consumption of electricity is based on two factors: (i) Amount of electric power and (ii) Duration of usage. Electrical energy consumed is taken as the product of electric power and time of usage. For example, if 100 watt of electric power is consumed for two hours, then the power consumed is 100 × 2 = 200 watt hour. Consumption of electrical energy is measured and expressed in watt hour, though its SI unit is watt second. In practice, a larger unit of electrical energy is needed. This larger unit is kilowatt hour (kWh) . One kilowatt hour is otherwise known as one unit of electrical energy. One kilowatt hour means that an electric power of 1000 watt has been utilized for an hour. Hence,

$$ 1 \text{ kWh} = 1000 \text{ watt hour} = 1000 \times (60 \times 60) \text{ watt second} = 3.6 \times 10^6 \text{ J} $$