What does a time-of-use rate mean?

Some users pay the same price-per kWh all the time. But many utility providers have a time-of-use rate structure that changes the price per kWh depending on a user’s power usage during the peak hours of the day, when their cost to deliver power is higher. These time-of-use rates can vary from a few cents more per kWh, to many multiples of the base per-kWh rate. Users will often seek ways to ‘shift’ their power usage to occur during the times of day when rates are lowest. An EnergyAware UPS can use the energy storage available in its batteries to reduce facility power demand during peak times and delay recharging those batteries until times when power cost is lowest, usually late at night.