A power company charges customers based on which one of the following?

The power company charges customers based on energy consumption, which is the correct answer. Energy is typically measured in kilowatt-hours (kWh), representing the total amount of electricity consumed over time. When customers receive their bills, they are charged based on the total energy they have used during the billing period.

This ensures that customers are billed in relation to how much electricity they actually consume, reflecting their use and encouraging energy conservation. Moreover, energy pricing can include tiered rates, where the cost per kilowatt-hour may increase with higher usage levels, incentivizing users to manage their consumption effectively.

The other options relate to important concepts within the electricity billing process. Power usage refers to the instantaneous demand for electricity but is not the basis on which customers are routinely billed. Time of consumption can influence electricity rates, especially if there are peak and off-peak pricing schemes, but the fundamental billing metric remains energy consumption overall. Demand charges apply to commercial customers based on their maximum power usage over a specific period but are less common in residential billing. Thus, energy consumption stands out as the primary basis for customer charges.