ORIGINAL REPORTING: How To Make Solar Power Plants Better
The 3 factors that determine solar plant performance; A new LBNL report outlines 3 variables that it says explain 92% of output differences between solar projects
Herman K. Trabish, April 21, 2016 (Utility Dive)
Editor’s note: As solar power plant costs get lower and therefore harder to cut further, getting more bang for the buck increases in importance.
Figuring out methods to maximize electricity output from solar panels is a challenge for utilities and solar developers alike. Small variations in daily performance can significantly affect the long-term output of an array. The three factors that can help power providers manage expectations and maximize performance of utility-scale plants are the amount of sun hitting the panels, the use of tracking, and how much load is on the inverter (inverter load ratio). Together, they account for 92% of the performance variation, according to a new report from the Lawrence Berkeley National Laboratory (LBNL).
With this data, utilities making rate-based investments or signing long-term contracts can better understand where these projects fall in the capacity factor spectrum. That will allow them to plan how they will invest with more confidence in to the profitability of the projects. The strength and concentration of solar energy hitting a panel, technically called the global horizontal irradiance (GHI), accounts for 71.6% of performance variations. The biggest determinant of GHI is a project’s location. Tracking, or the way a panel follows the sun, will also play a part in how well the solar array performs. For each 1 kWh/m2/day increase in GHI, measured in 2014, the model predicts a 4.23% increase in 2014 capacity factor for fixed tilt arrays, compared with a 6.08% increase for projects built with tracking. The third major factor, the inverter load ratio (ILR), describes how much direct current generation from a project’s modules is converted to alternating current by the inverters and sent to the grid…