There is a common phrase in the world of data and systems management: “Garbage in, garbage out.” If the data being put into a system is inaccurate or garbage, then that is exactly what you’ll get as an output.
Solar developers, EPCs and financiers want to see accurate energy production models during the feasibility study stage of potential projects, so it is crucial for solar professionals to understand the software tools and calculators used in energy production estimates.
The first software platform many of us in the solar industry are introduced to is NREL’s PVWatts Calculator. The PVWatts Calculator allows users to easily develop estimates of the performance of potential PV installations. It is a great tool to get your feet wet on basic PV system performance estimates, but when you begin work on projects requiring more detailed reports, you’ll want to graduate to software platforms like PVsyst.
PVsyst is a software package for the study, sizing and data analysis of complete PV systems. It deals with grid-connected, stand-alone, pumping and DC-grid (public transportation) PV systems, and includes extensive meteorological and PV system component databases. PVsyst is used by many designers and solar professionals across the industry.
Whether using PVWatts or PVsyst, there are many default settings that may not be the most accurate to use. Many default settings are precise to your general location, using local weather patterns, environmental conditions and average solar equipment specifications. But default settings won’t always apply to your particular system and may throw off your calculations. For example, PVWatts uses a default value for shading even though you may not have shading in your particular situation. This will have a huge effect on your production estimates.
Environmental and PV equipment component factors that are even slightly off can result in inaccurate production estimates and financiers that are displeased with underperforming systems, especially if there are production guarantees. The project designer will take the heat, and this is not an ideal situation to be in.
As a solar professional, understanding how to use these software tools at a very detailed level is a crucial part of your professional development. To help people new to the industry and new to using software tools like PVsyst, Solar Energy International (SEI) developed a short course targeted at beginning users. The course “CE524: PVsyst for PV system production modeling” was developed to explain how to create accurate production estimates for any sized PV system. In this online course, students learn how to find and import correct meteorological data, create system variants and accurately define the orientation, shading scene and detailed system losses. Students are confidently simulating production and printing reports to share by the end of the course.
In order to keep project developers and financiers happy and keep growing your professional solar career, it is critical to have correct reports and design plans. The first step to getting it right is to be trained on accurate data methods. Keep the garbage from going in and you will have a high level of confidence that your designs will be cranking out clean and reliable energy for decades to come.