Power is measured in watts, which we usually relate to electrical appliances, but it applies to all living and moving things. It is the amount of energy used per second. The power might come from electricity in the case of a washing machine, or a petrol engine in the case of a car, or food (then ATP) in the case of animals. To get things into perspective, 1 joule of energy is the amount used to lift an apple out of a 1-metre-deep barrel; 1 watt is the power required to lift that apple 1 metre in 1 second. To lift ten apples (or about 1kg) up 1 metre in 1 second takes 10 watts of power.
