Solar cell efficiencies and photovoltaic module performances are typically only measured under standard lab conditions. However, in reality, photovoltaic modules are operated in the field under conditions that are substantially different from these standard lab conditions.

MUNICH, Germany—May 30, 2017—At this weeks Intersolar Europe, imec, the world-leading research and innovation hub in nano-electronics, energy, and digital technology, and partner in EnergyVille, will introduce simulation software that accurately predicts the daily energy yield of solar cells and solar modules under varying meteorological and irradiation conditions. Imecs model combines optical, thermal and electrical parameters to provide detailed insight on thermal gradients in the solar module. The model integrates the effect of these gradients, resulting in a significantly better accuracy (root mean square error of only 2.5 percent) than commercially available software packages for energy yield estimation.

Solar cell efficiencies and photovoltaic module performances are typically only measured under standard lab conditions. However, in reality, photovoltaic modules are operated in the field under conditions that are substantially different from these standard lab conditions. They are exposed to varying meteorological conditions in terms of irradiation, temperature and wind, which, in addition, all vary during the course of the day. In contrast to most existing models for energy yield calculation, imecs model starts from the physical parameters of the solar cells and the used materials, and includes on top of that their variations due these changing external conditions. In this way a ‘closer to reality model is obtained, enabling a more precise assessment of the effects of solar cell and module technology changes on the energy yield of these photovoltaic cells and modules.

Imecs simulation software features a coupled optical-thermal-electrical approach and provides detailed insight on thermal gradients in the solar module and their effect on energy yield. The incorporation of wind and thermal transient effects produced a highly accurate calculation of daily energy yield with a root mean square error of only 2.5 percent, under strongly varying meteorological conditions (e.g. clouds passing by, changes in wind speed, ....) compared with the actual measured output. This is significantly better than energy yield calculations that could be obtained using commercial software packages under these varying weather circumstances.

"This record accuracy was obtained thanks to validation tests under controlled circumstances, such as wind tunnels, as well as from detailed data series with fine time granularity from PV modules in the field," stated Hans Goverde, researcher at imec.

"It is an excellent tool to make a rapid assessment of material and technology changes at the cell and module level and their influence on the levelized cost-of-electricity," noted Jef Poortmans, scientific director photovoltaics at imec. "Moreover, it is also the ideal starting point to come up with significantly improved short-term energy yield forecasting, which will lead to lower lost opportunity costs and better energy management systems for PV power plants as well as residential solar systems. This means that our model could e.g. become very useful for PV plant operators and electricity grid operators, enabling them to better forecast the short-term varying output of PV power plants, in this way limiting curtailment situations and grid balancing issues, and hence create more value across the full renewable energy value chain."

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About imec
Imec is the world-leading research and innovation hub in nano-electronics, energy and digital technologies. The combination of our widely acclaimed leadership in microchip technology and profound software and ICT expertise is what makes us unique. By leveraging our world-class infrastructure and local and global ecosystem of partners across a multitude of industries, we create groundbreaking innovation in application domains such as healthcare, smart cities and mobility, logistics and manufacturing, and energy.
Imec is a partner in EnergyVille (www.energyville.be). EnergyVille is an association of the Flemish research centers KU Leuven, VITO, imec and UHasselt in the field of sustainable energy and intelligent energy systems.
As a trusted partner for companies, start-ups and universities we bring together close to 3,500 brilliant minds from over 75 nationalities. Imec is headquartered in Leuven, Belgium and also has distributed R&D groups at a number of Flemish universities, in the Netherlands, Taiwan, USA, China, and offices in India and Japan. In 2016, imec's revenue (P&L) totaled 496 million euro. Further information on imec can be found at www.imec-int.com.