Micro-Climates & Localized Weather Patterns:

• Localized micro-climates can be created by forests, urban areas, or bodies of water, which can lead to variations in temperature, precipitation, wind patterns and irradiance. Urban areas, known for the heat island effect, can be warmer than surrounding rural areas. Additionally, varying topographies such as valleys and plains can further influence these climatic conditions, contributing to distinct weather patterns even within a relatively short distance.
• Localized weather patterns, including the frequency of cloudy or rainy days, can impact solar power generation. Persistent cloud cover reduces the amount of solar radiation reaching the panels.

System Design and Configuration:

• Every project is uniquely designed to the site’s topography, utilizing a wide variety of system components and manufacturers. Differences in chosen system components and installation practices can account for differences in system performance.
• Mounting structures can be fixed-tilt, seasonal-tilt or single-axis trackers. Energy output differences can be caused by undulating topography and slightly varying tilt angles.
• Differences in DC wiring system designs, current aggregation method, and array spacing can also contribute to differences in energy production.
• Variances with inverter voltages, efficiencies, and inverter types, including string inverters or central inverters, can impact overall energy yield.
• There can also be meaningful variances in energy yield measurements depending on AC system transformers, and AC medium/high-voltage distribution losses.
• While typical PV plants are designed to minimize shading, systems can have variances in building or electrical pole shading that can impact energy production.

Operation & Maintenance:

• The soiling of PV modules can be influenced by dust, dirt, pollen, bird droppings, and other particulate matter on the surface of the solar panels. This can significantly reduce their energy output by blocking sunlight.
• Depending on the amount of soiling, cleaning schedules can vary from project site to site.
• Regular maintenance of electrical equipment such as fuses, breakers and measuring equipment including soiling and weather stations can have a significant impact on energy yield.

Grid Integration and Support:

• The grid or plant operator can have a sizable impact on the overall output of a solar plant through curtailment, transmission limitations, power factors, and voltage and frequency stability support.