I think "time period" is too vague here: "any time period" is "any period of time" and doesn't necessary mean "periodo horario", which refers to a period during the day (or night). This is the important point here: it's talking about electricity produced, for example, during the night and saved for use during peak periods of the day.

Although "time of day" may seem to refer to a particular hour of the day, in fact it refers to a period of the day (or night) as well. It is the standard term when talking about peak and off-peak electricity consumption:

"Time of Day metering (TOD), also known as Time of Usage (TOU) or Seasonal Time of Day (SToD), metering involves dividing the day, month and year into tariff slots and with higher rates at peak load periods and low tariff rates at off-peak load periods. [...]
TOD metering normally splits rates into an arrangement of multiple segments including on-peak, off-peak, mid-peak or shoulder, and critical peak. A typical arrangement is a peak occurring during the day (non-holiday days only), such as from 1 pm to 9 pm Monday through Friday during the summer and from 6:30 am to 12 noon and 5 pm to 9 pm during the winter."
http://en.wikipedia.org/wiki/Electricity_meter#Time_of_day_m...

"Time-of-day rates are based on the time in which you use electricity. Similar to peak pricing used for air travel, cell phones, hotel stays, etc., time‑of‑day electric rates mean that you pay lower rates during periods of low demand (i.e., off-peak) and higher rates during periods of maximum demand (i.e., peak)."
http://www.ctenergyinfo.com/dpuc_time_of_day_rates.htm


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Note added at 1 hr (2012-01-31 19:09:31 GMT)
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Another possibility is "period of the day", though this is just a much less usual way of saying the same thing. But "period" or "time period" alone won't do here. If you say "the energy generated in any period [...] can be delivered in other periods", there is nothing to indicate it refers to "periodos horarios": morning, afternoon, evening, night, or whatever. "Any period" could be any duration from an hour or two to a couple of days or more. Even if you assume it means hours rather than days, it could be any period of the day or night. But that of course it not what this means. The reader might guess the right meaning, but that's not good enough. The words "of day" have got to be included here.