What measured in watts?

Power is measured in watts. This can mean either the power that something produces as it works, or the power that is needed to drive something. A watt is not a very big unit of power. Powerful machines are therefore graded in kilowatts(KW) or megawatts(MW). A kilowatts is 1,000 watts and a megawatt is 1,000,000 watts. The watt is named after James Watt, the British engineer who developed the steam engine in 1760s.