 Monitoring Photovoltaic (PV) System Performance in Tucson using Metering Provided
by Tucson Electric Power (TEP)
Locate the Photovoltaic (PV) meter installed along with your PV system.
This meter can be identified by the fact that it displays a single digital
number and will be connected to your inverter by electrical conduit.
Read the value displayed by the PV meter at regular intervals, for example
once a month, and take the difference of these monthly numbers to determine
the amount of energy your PV system produced during a given month. As a rule
of thumb, a properly operating system should produce approximately 150KWH
(Kilo Watt Hour) per month for each KW of solar panels installed. For example,
a 3KWDC (Kilo Watt Direct Current) system reading on the 1st of June may be
2639 and on the 1st of July may be 3093 indicating a monthly solar production
of 454KWH.
Electricity Supplied by TEP
 Locate the TEP revenue meter next to your electrical service panel
which displays three digital values:
- DEL = Electricity DELIVERED by TEP to your home over the course
of a day.
- REC = Electricity RECEIVED by TEP from excess production of your PV system
during sunny parts of the day.
- NET = The difference between delivered and received electricity which
establishes the amount TEP bills you each month.
Read the value when “NET” is displayed on the meter at regular intervals,
for example once a month, and take the difference of these monthly numbers
to determine the amount of energy (KWH) you bought from TEP during a given
month. For example, a net meter reading on the 1st of June may be 4649
and on the 1st of July may be 4776 indicating you bought 127KWH from TEP
over a month period.
Total Household Consumption
The total amount of electricity consumed by your household over the month is
the sum of PV production and the monthly “NET” value. For example, if PV
production was 454KWH and TEP supplied electricity was 127KWH, then total
consumption of the home would be 454KWH + 127KWH = 581KWH.
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