# One step towards energy conservation

## Calculation of Electrical Energy Units that can be saved

All mobile phone and tablet chargers across the world have a pre-defined star rating. The star rating of a charger is related to the power consumed by the charger itself when connected to a power outlet. A zero star charger consumes the maximum power under no-load, i.e. when the charger is still connected to the supply after the phone has fully charged. A 5-star charger consumes the least power under no-load.

The following table tabulates the amount of electrical energy units wasted in a year for the different types of chargers due to unwanted excess charging.

 Star rating of chargers No-load consumption(W) Assumed Excess Charging Time (Hr) Electrical Units Consumed (KWH) Electrical Units Consumed in a year Units consumed in a year by India* a b c = a x b/1000 d = c x 365 U = d x 1270 Mn Zero-star 1 2 0.002 0.73 927,100,000 1-star 0.5 2 0.001 0.365 463,550,000 2-star 0.35 2 0.0007 0.2555 324,485,000 3-star 0.25 2 0.0005 0.1825 231,775,000 4-star 0.15 2 0.0003 0.1095 139,065,000 5-star 0.03 2 0.00006 0.0219 27,813,000
* Population of India = 1270Mn
A country like India with a population of about 1.27Bn can save energy anywhere from 30Mn units to 1Bn units in a year!!