PVz: Analysing energy bills for sizing solar PV systems

PVz is a tool designed by solar PV industry professionals to facilitate the process of analysing electricity usage in order to choose a solar system size most appropriate for the client. The spreadsheet-based program makes it easy to see when and how much electricity is used throughout the day. It is compatible with any major make of electricity interval meter and power quality analyser, including HT Italia, Fluke, Yokogawa, and Elog.

Why is it so important to size a solar PV system appropriately?

This may seem like a silly question these days, but in the days when generous solar feed-in tariffs existed in almost every state of the country it made sense to install as large a system as roof space and budget would allow. This is because feed-in tariffs financially rewarded solar system owners for exporting their solar power to the grid. Nowadays, however, ‘self-consumption’ of solar energy is the key to making solar PV systems a worthwhile investment for homes and businesses alike.

This reality is already widely understood and accepted by the thousands of people who have chosen to invest in a solar photovoltaic (PV) system in the post feed-in tariff environment, where power exported to the grid is worth only around 8c per kilowatt-hour (kWh), or in states such as WA where network owners prohibit the export of excess electricity to the grid. By contrast, self-consuming this solar power could save the system owner in the range of 18-28c/kWh. This means that it is essential for anyone considering going solar to understand their home electricity usage patterns and size their solar system accordingly.

How PVz assists with PV system sizing

PVz data analysisMany homes & businesses have little idea about how much electricity they consume throughout the day, month, and year, and would therefore have no idea what size solar system would best suit their needs. Even solar PV installation companies that have ample experience in realm of system sizing may rely mainly on the customer’s power bills, which do not provide information finer than average daily or monthly usage breakdowns. Installers may therefore be seeking a solution that simplifies the analysis & sizing process and yields more accurate results. This is exactly what the developers of PVz have endeavoured to do.

The software uses the half-hourly interval data from the customer’s electricity meter in its analysis, contrasting it visually against statistical solar PV system energy production data. The resultant graph is accessible, easy to interpret, and can be used by installers in customer proposals as part of a sales strategy. In the near future the PVz software will also suggest solar system sizes based on the customer’s self-consumption and export preferences. Interval data for use with PVz must be sourced from the customer’s electricity meter. Analog meters do not produce this data, but electronic billing meters do, usually in CSV and XLS format. PVz is compatible with these file formats. These files should be available through the customer’s electricity retailer. In the event that no data can be sources, a PV installer can log the customer’s point of connection with a power quality analyser and upload the data into the PVz tool.

Contact & PVz trial info

Free trials of PVz are available. If you are interested in learning more, please email Karlos Silva at: silvk3@gmail.com. Karlos and his team are still in the process of developing PVz and welcome feedback on its functionality. Download: PVz FAQ & Overview (PDF)

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