Accurate determination of PV yield by temperature and spectrally dependent I-­V measurements

Accurate determination of PV yield by temperature and spectrally dependent I-­V measurements

Internship Description

The performance of photovoltaic (PV) cells and modules is ultimately characterized by the determination of the power conversion efficiency (PCE) by measurement of the current­ -voltage (I-V) response of the device under illumination. Standardization of this measurement (in terms of cell/module temperature, irradiance, and incident light spectrum) allows for a simple means of comparing different devices. However, accurately determining the yield of a device (i.e. its total energy output over its lifetime) once deployed in the field, in conditions that vary from the standard test conditions, is not necessarily possible from this data. This becomes increasingly significant as PV installations - and so capital investments, project budgets and leverage - get progressively larger. Small changes in yield from a power plant over the course of its approximately 30 year projected lifespan can have a large impact on the project's financial viability. Currently, this uncertainty is typically accounted for by a scenario analysis in the project's cash flow model which is often used to determine a long term Power Purchase Agreement at a fixed cost. A more accurate determinations in yield can result in more confidence that installers, and their lenders, will reap profits from their investment over the lifetime of the power plant (typically determined over 30 years). 
The KSC recently acquired an advanced solar simulator that is able to accurately mimic a given input spectrum by varying the light output from an array of 22 LEDs of differing wavelengths ranging from the UV to the near IR. The Solar Center also has access to spectral irradiance and field operating temperature data from PV modules operating on campus. In this project we propose to investigate the yield output of different types of crystalline silicon solar cells by taking measurements of their PCE at temperatures and spectral irradiance values that accurately reflect operating conditions in Saudi Arabia. The data acquired in this project will not only facilitate the accurate projection of energy yields from PV deployed in Saudi conditions, but will also help direct research efforts at the KSC aimed at tailoring solar cell designs that are optimized for high insolation, high temperature conditions. By developing a we will also be able to accurately assess the value and payback time of different technologies that are being developed in the KSC that are aimed at mitigating thermal energy losses at the cell and module level. 

Deliverables/Expectations

The visiting student will be trained on how to operate the IV tester, how to input spectral data and interpret the outputs (temperature and spectrally dependent I-V data, Suns-Voc, and dark 1-V). This data will be collected for a vast array of operating conditions that will reflect the field operation over the course of an entire year for c-Si cells of competing technologies. It is expected that this data will be written into a report suitable to ​publication. The knowledge gained will also be a valuable guide to steer the future research efforts, and assess technologies developed within the KSC, that are aimed at optimizing cell and module technologies for Saudi conditions.

Faculty Name

Field of Study

​Marine Science