PV Asset Manager User Guide


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PV Asset Manager is offered at four different levels of service, with increasing performances.

Basic features are common in all versions and reflect the goal of the system, designed to provide the owner of the PV plant the management tools to control plant productivity, financial performance, maintenance service, i.e. the QoS (Quality of Service).

In fact, all of the packages allow complete management of the business through productivity and financial indexes, deviations, forecasting, automated management of PV plant malfunctions.

The difference is in the quality and timeliness of data, indexes, alarms, resulting from the data acquisition services:

no installation required, based on user data entry
  • SAT (free!) 
no installation required, energy production meter data entered by user automatic detection of solar irradiation by meteo satellite
installation of a sensor for energy production meter remote reading automatic detection of solar irradiation by meteo satellite
installation of a sensor for energy production meter remote reading, installation of a meteo station for local meteo data determination









GOLD version is currently under test and therefore it is not offered to the public.

SILVER and SAT version are immediately  activated at user subscription.

In versions SAT, SAT+, GOLD, it is possible to acquire the PV Plant Historical Rating, calculated by mean of actual solar radiation based on weather satellite immages. 

See the Products comparation table.



In this section it is described the basic organization of the system, common to all versions of the PV Asset Manager. We suggest a preliminary reading of key concepts and indexes (at the end of this section).


The system requires a first step to create a new plant and to set up initial technical and financial parameters. Optionally it is possible to tune the weather forecast data and productivity (PR) monthly references.

Once this phase has been completed, the reference Business Plan and the updated Business Plan (which is initially the same as that of Reference), are automatically produced.

Data entry

The user should then entry month to month historical data, at least those related to energy production; differently the system will use reference data. It is possible to entry one data at a time or several months together using cut & paste from Excel (fast data entry). If the sun irradiation data are not available, the estimated data is used. It is also possible to specify monthly all the economic data of cost and revenue (or leave the expected ones).

Once this is completed, the Updated Business Plan automatically changes as follows:

  • Past: data are updated according to the entry
  • Future: data are modified suitably according to past data (see below)

The entry of energy meter data should be carried out monthly, except in the SAT+ and GOLD packages where it is done automatically.

In versions SAT, SAT+, GOLD, historical solar irradiation data related to the photovoltaic plant can be acquired through  the optional "Historical Meteo Data" service, based on actual observations from weather satellite.

Financial reports

  • A Reference Business Plan based on set up initial forecast
  • An Updated Business Plan, based on real collected data, with forecasts automatically modified  on the basis of the collected data
  • Annual Reports (final and estimated)

Technical Reports:

  • General Report: includes a comparison between real and expected indexes: sun irradiation, PR, lost sun hours, PR net of lost hours, returns, cash-flow, IRR.
  • Long-term charts: showing the monthly trend of real, estimated and performance data and indexes.

Management of PV plant malfunctions

Detection of malfunctions (PV plant downtimes, even partial ones) is the key to understanding the real PV plant output and maintenance service quality.

In SAT+ and GOLD versions, the system recognizes automatically a malfunction status, while in SILVER and SAT ones, it must be entered by the user.

The system then automatically calculates lost sun hours: in the Silver package it is done by using the average sunlight for the period; in the versions SAT and SAT+ using satellite weather detection, in the GOLD version using the sun radiation measured in real time by the sensor supplied to be installed at plant site.

Then the consequent economic loss is automatically determined and a malfunction report form is created, that the user – tipically a maintenance firm operator – should fill as soon as possible.

In relation to malfunctions happened in the past, prior the PV Asset Manager start, the user can put in one malfunction at a time or import data from Excel, using a quick entry function.

Quick View:

The list of available PV plants is shown with their relative main performance indexes, grouped in financial and production sections.

In the case where the user has several plants, in the Quick View and Financial Reports are available multi-plant cumulated reports and indexes.

Key concepts and indexes

  • PV plant output

The PV plant performance PR (Performance Ratio) is normally defined as follows:

PR (%) = actual energy yield / solar energy input through PV panels


Actual energy yield is expressed in kWh / kWp, which is the energy measured by the output meter divided by the PV plant rated output

Solar energy is expressed in kWh/m2

(In the same way, the immediate PR is a ratio between powers rather than energies).

  • Assessment of lost sun hours and losses caused by malfunctions

Traditional measurement systems do not “record” PV plant downtimes or malfunctions: it is therefore impossible to distinguish the real PR from that affected by these output losses and it becomes useless to compare real and expected performance.

The system also calculates a PR affected by these malfunctions, that is the PR net of lost sun hours, and then measures the consequent energy output and eventual economic losses.


The list of failures shows that there have been several events of a malfunction, which resulted in a total loss of 143.1 solar hours, which yielded a lower production of 45,953.45 kWh, corresponding to an economic loss of € 18,171.

The glance in the graphs is immediate: the real PR (green line in the middle graph) has a slump in May, when there is a peak solar hours loss (bottom graph). The PR net solar hours loss (blue line in the middle graph), however, always remains above the expected one (yellow line). For this reason, production is in line with that expected (first graph) except in the month of May.

Note: Peak sun hour = 1 hour with sunlight intensity at the nominal value of 1,000 W / m2, with a full-working system. This means that if sunlight intensity is 600 W/m2 and the entire system does not work  for 1 hour, there are 0,6 lost “sun hours”. If in that hour just a half of the system does not work, just 0,3 sun hours are lost.

  • Financial return

The financial return IRR (Internal Return Rate) depends on the cash flow established in the Business Plan, clearly after the initial cash out (negative cash). 

If the owner has obtained a bank loan, the capital taken into account (equity) corresponds to the whole capital minus the obtained loan. This IRR is before tax.


GOLD package

In the GOLD package, the PV plant production and meteo data are acquired automatically in real time by mean of the sensors provided, to be installed at the plan site. Furthermore, the user is provided with additional facilities described below:

  • PR standardization: PR net of temperature losses

PR measure (violet line in the chart) is objective but it is hard to compare, as it changes considerably with temperature variation of the solar panel.

In other words, if the PR is based on data gathered over a 12 month period it can be considered a valid index, but for short periods it is less useful. SunXman also calculates and provides the PR net of temperature losses. 

The Net PR (above brown line) has more stable and comparable values, so it becomes the real index of PV plant performance. 

The system estimates the module temperature with a high level of accuracy, according to the sunlight, type of mounting of the modules (roof or ground mount), ambient temperature and wind speed.

  • Automatic gathering of production losses and malfunction status, based on the constant comparison between PR net of temperature losses and the established threshold.
  • Automatic alarms and warnings in real time in case of output net of temperature losses below the established threshold.

In the above example, the system automatically recognizes a 50% decrease in the PR net (ie net of losses in temperature) for two hours, and determines the solar hours lost in that period, that is, the actual solar energy during the same period.

  • Automatic calculation on the daily and peak PV plant Rating
    A stable situation and the most precise solar energy measurements are needed to correctly evaluate the performance and establish an PV plant rating. The system automatically identifies clear-sky conditions (stable clear sky) and calculates the PR net of temperature losses and elaborates the PV plant rating on the basis of this value.
  • Real time Report: data and indexes updated every 15 minutes
  • Whole Report for every day: daily data and indexes
  • Intra-day charts for every day: charts at 15 minute steps
  • Monthly charts: charts of data and indexes on measured every each day


SAT+ package

In SAT+ version, production data are automatically collected in real time thanks to the sensor supplied, to be installed on the production meter while data daily sun radiation are automatically acquired by mean of measurements from weather satellite.

The program provides the following additional features:

  • Automatic detection of the daily productivity (PR)
  • Automatic daily alarms and warning in case of productivity below the threshold of respect
  • Automatic calculation of daily Rating

For a measure of performance that can be useful to establish a rating system, a stable situation is needed to have a measure of the solar energy as accurate as possible. The system will automatically check if there were "clear-sky" conditions and then will give a rating vote on the basis of the comparison between the daily PR with the reference PR in that month.

  • Full report for each day: data and indexes of the day
  • Intra-day charts for each day: 15 minute charts steps of energy production
  • Monthly Graphs: graphs of the data and indexes collected on each day

To subscribe to the SAT+ version, the PV plant must be first created at the SAT (free) level: look at the additional service guide.

SAT package

In the SAT version, data daily sun radiation are automatically acquired by mean of measurements from weather satellite. This package does not require any installation and therefore the production meter data must be entered manually.

There are the following additional features:

  • Daily productivity (PR), automatically when the user reads and inserts the production meter data at the beginning and end of the day;
  • Automatic calculation of daily rating;

If the user inserts the production meter data at the beginning and end of a specific day, the system will automatically check if there were "clear-sky" conditions and then will give a rating vote on the basis of the comparison between the daily PR with the reference PR in that month.

  • Daily Report: data and indexes available at the end of each day
  • Monthly Graphs: graphs of the data and indexes available for each day


SILVER package

This version implements all the basic functionality of the system. There is no installation, and then the production meter figure must be entered manually. The solar radiation used is the provisional one (estimated), subject to the possibility of correction by the user.


HISTORICAL RATING (only for italian territory)

The historical data of solar radiation relative to the PV Plant, at least those of the 12 months preceding the start of the PV Asset Manager, are useful for:

  • Provide immediately PV plant rating
  • Provide relevant data to PV Asset Manager forecast algorithms


In versions SAT, SAT + GOLD, it is possible to acquire the PV Plant Historical Rating, calculated by mean of actual solar radiation based on weather satellite immages..
The service provides solar radiation observed daily in the Municipality indicated. The data are automatically associated with the PV plant by the PV Asset Manager.


About us

Our mission is to provide entrepreneurs and top management timely and clear indicators on the performance of their business, not only with respect to the provisional data, but also compared to those achieved by the best practice.