Watt

The watt is defined as:

$1\text{ W} = \frac{1\text{ J}}{1\text{ s}}$

One watt means one joule of energy is transferred per second.

Common multiples: 1 kW = 1000 W; 1 MW = $10^6$ W; 1 GW = $10^9$ W.

Typical power ratings: LED bulb 10 W, laptop 60 W, kettle 2000 W, electric shower 8000 W, power station $\sim 1$ GW.