Published on August 6th, 2019 |
by Charles W. Thurston
August 6th, 2019 by Charles W. Thurston
The days of over-designing and over-building solar power plants to make up for unforeseen generation losses are gone. This is largely thanks to the emerging solar strategy of pursuing every tenth of a percent of system performance by better understanding the impact of equipment specifications, plant monitoring, and maintenance on the Performance Ratio, and therefore on the bottom line.
The industry is in the midst of a technology boom that is increasing the granularity of solar design improvements, with enhanced monitoring and advanced algorithms to fine-tune PV plant operations and management from a host of perspectives.
Granularity in measurement and data analysis enables more efficient operation, which results in a higher energy yield. This is because it pinpoints substandard functionality, enabling designers to improve systems and operators to enhance yield through remedial action.
This detailed monitoring and analysis can begin with the most basic of environmental problems, soiling of PV modules. For example, Kipp & Zonen’s DustIQ monitors the loss of light transmission caused by dust that can build up rapidly and results in a loss of energy conversion in the solar cells.
This more granular monitoring also takes place at the power optimization level, within sophisticated smart inverters that are now attuned to slight deviations from the expected performance and use technologies such as maximum power point tracking, for example Huawei’s new FusionSolar string inverters.
Software supports bifacial granularity
One of the elements of evolving solar technology that enables more granularity is better software. At the 2019 PV Systems Symposium solar industry meeting in Albuquerque, research and development experts gathered to compare notes on solar modeling software advances, building on widely used plant design programs by PVsyst and other companies.
A hot topic is the increasing interest in the advantages of bifacial modules, which gather reflected light from the surface below on the rear face and can boost yield by double-digit percentages. Among new approaches that take into account bifacial design issues is a trend towards three-dimensional modeling, which should also include soiling effects. This and other new technologies were displayed and discussed at the Symposium in May, which was co-sponsored by Sandia National Laboratories, CFV Solar Test Laboratory, and the Electric Power Research Institute (EPRI).
One new design solution highlighted is from Australia’s PV Lighthouse. Its SunSolve software uses high performance ray tracing with SPICE, an open-source electronic circuit simulator. The company is using its software to model bifacial systems, incorporating real world data sets, including weather measurement feeds from the National Renewable Energy Lab (NREL), resulting in some two billion ray calculations. That is granularity!
Another solar software technology development underway is at the University of Iowa, where a team is developing a performance prediction model that uses a reverse ray-tracing method, based on Radiance and Python software. The Iowa project is being funded by the US Department of Energy SunShot National Laboratory Multiyear Partnership, or SuNLaMP.
NREL’s V3 Bifacial Radiance software is being used to investigate single-axis tracking bifacial design variables; including tracker table height and torque tube clearance and table separation. Such software programs are pro