PVSC PROGRAM
Tutorials are a fun and educational tradition of the IEEE-PVSC Annual Conference. These extended sessions will take place the Sunday before the conference event dates. Tutorials give a deep insight into selected research & development topics and serve both as an expert review of the field for all, as well as an introduction for newcomers. The tutorials are given by some of the most recognized and experienced scientists in the field. All tutorials come with a set of slides which are an indispensable source of information that you will not find anywhere else!
Tutorial sessions will take place on Sunday, June 11, 2023.
AM Tutorials will start at 9am Atlantic Standard Time and PM Tutorials will start at 1pm Atlantic Standard Time.
Tutorial AM2: PV Systems Modeling with Python, an Interactive Introduction
Tutorial AM3: Tandems / Multijunction Solar Cells
Tutorial AM4: Experimental Considerations for Estimating Degradation in PV Modules
Tutorial PM2: Terahertz Spectroscopy: A Contact Free Probe of Photoconductivity
Tutorial PM3: Multiscale Characterization of PV Degradation and Performance Limitations
Tutorial PM4: Grid Integration
Click below to learn more about each tutorial.
Tutorial AM1: Fundamentals of Photovoltaics
Instructor:
N.J.Ekins-Daukes, UNSW Sydney, Australia
Tutorial Description
The tutorial will begin by surveying the properties and availability of sunlight, introducing the necessary measures and some commonly used data sources. A simple thermodynamic model for solar power conversion will be established to place an upper bound to the conversion efficiency. It will then be shown that using a semiconductor absorber leads to the usual measures for solar cell performance, short-circuit current, open circuit voltage and fill factor and introduces additional constraints to photovoltaic power conversion leading to the Shockley-Queisser efficiency limit. The carrier transport and recombination processes that are present in practical solar cells will be discussed in the context of Shockley’s diode equation. Analytical models for solar cell dark current, quantum efficiency and reciprocity between absorption and emission will be introduced.
Having established a conceptual framework for PV devices the present laboratory status and manufacturing of several solar cell technologies will be surveyed, including those made from crystalline silicon, III-V, CdTe, CIGS, organic and perovskite in both single junction and tandem architectures. The application of these solar cells in PV power systems will be discussed together with the economic and life-cycle metrics that are commonly used to determine the feasibility and desirability. The tutorial will conclude with a brief perspective on possible future scenarios for PV power generation and technological evolution.
Dr N.J.Ekins-Daukes (Ned) is a Professor at the School of Photovoltaic & Renewable Energy Engineering at UNSW Sydney in Australia. He received his first degree in Physics & Electronics from the University of St Andrews in Scotland and PhD in Solid State Physics from Imperial College London in 2000. He subsequently worked as a JSPS research fellow at the Toyota Technological Institute in Japan, he held full-time academic positions at the University of Sydney and then Imperial College before taking up his present position at UNSW Sydney. His research aims to fundamentally increase the efficiency of photovoltaic solar cells towards the ultimate efficiency limit for solar power conversion of 87%.
Tutorial AM2: PV Systems Modeling with Python, an Interactive Introduction
Instructors:
Silvana Ayala Pelaez, National Renewable Energy Laboratory, USA
Mark Mikofski, DNV, USA
Tutorial Description
From development to deployment and management of assets, PV modeling is an exciting area with challenges and the use of big data from weather to performance monitoring. Modeling tools for all aspects of photovoltaic systems are rapidly growing, and there are solutions for many research questions you might want to explore. Python is becoming one of the scientific languages of choice, and many open-source tools are now available for PV modeling. This tutorial will focus on teaching attendees PV modeling in python through PVlib.
In this interactive tutorial, we will go from getting acquainted with some common data used or measured in PV systems (i.e., weather) to modeling the AC energy output of a single-axis tracker system. This includes learning and simulating sun position, plane-of-array irradiances, single-diode models, temperature models, and inverter output. We will review common vocabulary around python and common PV data aggregation by hour, week, month, and visualization. The tutorial will finalize with an overview of other available open-source tools for other aspects of modeling PV systems and novel ideas on data science in the PV field.
It is highly recommended attendees of this tutorial bring their laptops. No pre-installed software is needed.
Tutorial AM3: Tandems / Multijunction Solar Cells
Instructor:
Myles Steiner, National Renewable Energy Laboratory, USA
Emily Warren, National Renewable Energy Laboratory, USA
Description
This tutorial will give a general introduction to the field of tandem solar cells for the use in terrestrial and space systems. It will start from basic theoretical considerations and explain the benefits of using several pn-junctions to convert the broad solar spectrum into electricity. Since III-Vs have historically dominated the field of multijunctions and high efficiency photovoltaics, we will review III-V multijunctions as a model system for other tandems. Some of the specific requirements for the use of multijunctions in different environments will be introduced, such as high current capacity for concentrators, radiation hardness for space applications, and low cost for one-sun applications.
New and on-going efforts toward hybrid tandems, combining cells of different material systems, will then be covered in detail. Silicon- and perovskite-based tandem devices offer the promise of similarly high conversion efficiencies as traditional tandem III-Vs, but at a fraction of the cost. However, these integrated materials systems also come with unique issues that arise due to the various dissimilarities between the materials and the fabrication processes required for different technologies. We will look at the advantages and disadvantages of different material and interconnection combinations (e.g. 2T, 3T, 4T) in terms of efficiency, cost, and scalability.
Myles Steiner is a senior scientist at the National Renewable Energy Laboratory, in Golden, Colorado, where he leads NREL’s III-V Photovoltaics Core program. His work focuses on the development of III-V multijunction solar cells for terrestrial and space power generation, thermophotovoltaics for energy storage, and solar fuels by photoelectrochemical generation.
Emily Warren is a staff scientist at the National Renewable Energy Laboratory, in Golden, Colorado, where she leads NREL’s Tandem Photovoltaics Core program. Her research interests focus on the fabrication and modeling of multi-terminal tandem solar cells and modules. She also studies novel architectures for the creation of solar fuels and dabbles in heteroepitaxial growth of III-V materials on silicon nanoimprint lithography.
Tutorial AM4: Experimental Considerations for Estimating Degradation in PV Modules
Instructor:
Michael D. Kempe, National Renewable Energy Laboratory, USA
Description
Carefully controlled laboratory experiments and measurements can enable the determination of acceleration factors suitable for extrapolation to durability and performance of a fielded PV module. Ideally, a single mechanism can be identified with appropriate acceleration factors for extrapolation to the field. However, even with a single mechanism, the inherent uncertainty in these factors leads to uncertainty in the extrapolation which is greater the higher the acceleration factor. This course will explain how because of the wide range of acceleration factors for a given degradation mode, utilizing acceleration factors greater than about 10× will typically lead to unacceptable uncertainty in the results. Therefore, if even just a rank ordering of materials is desired, acceleration factors must be minimized which requires a good general understanding of the scale of the different acceleration factors for the degradation mode of interest.
In this tutorial we will discuss what the different purposes are for many of the accelerated stress tests used today. E.g., what is a qualification test, a highly accelerated stress test, a rank ordering test, or a service life prediction test. We will discuss how one can understand the relationship between test results and expected field performance. A single accelerated stress test condition cannot duplicate outdoor exposure for all possible degradation pathways; therefore, one must use targeted evaluation of material properties at different stress levels to determine the relevant acceleration factors and fit it to a model. We will also discuss how to interpret the results of experiments understanding what is relevant/not relevant, or not evaluated in a test. There are many common error people make in their test interpretations because they push the stress levels to be too harsh. This creates biases and can mask the relevant failure modes and mechanisms or will erroneously lead one to over design materials against things that aren’t relevant. Several case studies will be presented to illustrate appropriate interpretation of accelerated stress testing results.
Dr. Michael D. Kempe is a Senior Scientist in the PV Module Reliability Group at the National Renewable Energy Laboratory, where he studies the factors affecting the longevity of photovoltaic cells and modules. This includes both modelling and measuring moisture ingress into PV modules and studying its effect on polymer adhesion, device performance and component corrosion. This work also includes the development of a technique for measure the moisture permeation rates in films down at levels around 10⁻⁶ g/m²/day and the evaluation of edge seal materials. He is also studying the effects of UV radiation and heat on the mechanical, chemical, and electrical stability of PV packaging components. This effort is tied into creating better qualification tests that more accurately assess safety and are better predictors of long-term durability, including development of the solder bump test for backsheet evaluation. He has been a central participant in the development of many IEC standards including those for safety, durability, backsheets, retesting, encapsulants, and high temperature exposure. Dr. Kempe graduated summa cum laude with an undergraduate degree in Chemical engineering from the University of Utah and from the California Institute of Technology with a Ph.D. in Chemical Engineering. In addition to working at NREL, he has served on the board of directors for CORE electric cooperative for 16 years. This is a large coop with over 170,000 meters. Here he has shaped policy working to modernize operations paving the way for integration of more renewable energy.
Tutorial AM5: Tandems / Multijunction Solar Cells
Instructor:
Myles Steiner, National Renewable Energy Laboratory, USA
Emily Warren, National Renewable Energy Laboratory, USA
Description
This tutorial will give a general introduction to the field of multijunction solar cells for the use in terrestrial and space systems. It will start from basic theoretical considerations and explain the benefits of using several pn-junctions to convert the broad solar spectrum into electricity. Since III-Vs have historically dominated the field of multijunctions and high efficiency photovoltaics, we will review the III-V alloy system and the various techniques that are available for growing these highly crystalline semiconductors. Some of the specific requirements for the use of multijunctions in different environments will be introduced, such as high current capacity for concentrators, radiation hardness for space applications, and low cost for one-sun applications.
New and on-going efforts toward hybrid tandems, combining cells of different material systems, will then be covered in detail. Silicon- and perovskite-based multijunction devices offer the promise of similarly high conversion efficiencies as traditional tandem III-Vs, but at a fraction of the cost. However, these integrated materials systems also come with unique issues that arise due to the various dissimilarities between the materials and the fabrication processes required for different technologies. We will look at the advantages and disadvantages of different material and interconnection combinations (e.g. 2T, 3T, 4T) in terms of efficiency, cost, and scalability.
Myles Steiner is a senior scientist in the High Efficiency Crystalline Photovoltaics group at the National Renewable Energy Laboratory, in Golden, Colorado, where he works on III-V multijunction solar cells for terrestrial and space power generation, thermophotovoltaics for energy storage, and hydrogen generation by photoelectrochemical water splitting.
Emily Warren is a staff scientist in the High Efficiency Crystalline Photovoltaics group at the National Renewable Energy Laboratory, in Golden, Colorado, where she focuses on the fabrication and modeling of multi-terminal tandem solar cells and modules. She also studies novel architectures for the creation of solar fuels and dabbles in heteroepitaxial growth of III-V materials on silicon nanoimprint lithography.
Tutorial PM1: Performance Testing of PV Cells and Modules
Instructor:
Tao Song, National Renewable Energy Laboratory, USA
Nikos Kopidakis, National Renewable Energy Laboratory, USA
Tutorial Description
- 1. Fundamentals
- 2. Multijunction PV cells
- 3. Emerging PV cells including tandems
- 4. Emerging PV modules
- a. Definitions: irradiance (total, spectral), Standard Test Conditions (STC)
b. PV testing basics – Spectral response, current-voltage (I-V) characteristics
c. Translation of indoor test to STC – spectral mismatch, temperature corrections
d. Practical considerations: simulator classifications, temperature control
e. The PV calibration chain, traceability and the meaning of “ISO accreditation”
f. Measurements outside STC
g. Performance testing of PV modules
h. International Standards
- a. Spectral response measurements
b. Spectral matching and simulator considerations for performance testing of 2T cells
- a. Special considerations for performance testing single-junction perovskite and other emerging PV cells: spectral response and maximum power determination for single-junctions
b. Performance testing multijunction emerging PV cells: special conditions, sources of error and common measurement pitfalls
- a. Current status of perovskite and other emerging PV module performance measurements
b. Challenges of emerging PV testing as the technologies evolve
Nikos Kopidakis is a research scientist at NREL and the technical lead of the PV Cell and Module performance group. He has over 20 years of experience in PV research, including silicon, dye-sensitized and organic PV. His interests cover the performance characterization of PV cells and modules of any size and technology and new measurement techniques for novel and emerging PV. He has previously worked on new materials for PV applications and in spectroscopic techniques for characterizing their photophysics.
Tutorial PM2: Terahertz Spectroscopy: A Contact Free Probe of Photoconductivity
Instructor:
Jens Neu, University of North Texas, USA
Description
The development of solar materials is driven by a more in depth understanding of photoconductivity in materials. To gain such insight scientists utilize a large breath of characterization techniques, ranging from X-ray techniques to DC measurements. In this tutorial I strive to familiarize the audience with Terahertz (THz) spectroscopy, a contact free way to measure conductivity and photoconductive with sub-picosecond temporal resolution in micro-granular to single crystal samples.
THz spectroscopy is a very versatile technique that uses broadband probe beams, spanning from 100 GHz to 10 THz in bandwidth. These broadband signals are measured amplitude and phase resolved providing the complex conductivity of photoelectrons. Models fitted to these measurements provide not only DC-conductivity but also shed light on scattering mechanisms. Which helps us to understand how surface passivation, material composition, sintering temperature, and other parameters influence (photo)-conductivity.
This tutorial will explain the concept of time domain spectroscopy and guide the audience towards the more common representation of frequency resolved spectra. I will discuss optical pump THz probe (OPTP) and time resolved THz spectroscopy (TRTS). OPTP provides sub-ps time resolution granting insight into carrier lifetimes and trapping. TRTS complements this with complex photoconductivity data providing scattering times and carrier densities/mobilities. After presenting the instrumentational tools I will explain how we get from measurement to conductivity and what limitations apply. This explanation will have a particular emphasize on sample and material preparations needed for proper prediction of solar cell performance. I will close this tutorial by highlighting recent studies in which THz spectroscopy enhanced our understanding of solar processes in Perovskites, Metal Organic Frameworks (MOF), 2D Materials, and more.
Jens Neu received his Ph.D. from the Technische Universität Kaiserslautern (Germany) for his work on adaptive metamaterials. He then joined the Energy Sciences Institute and the Microbial Sciences Institute at Yale University (USA), where he studied emerging solar materials and environmental bacteria, respectively. Jens moved to the Physics Department at the University of North Texas (UNT) in 2023. His research group is focused on Terahertz spectroscopy on anything that is fun. A particular focus lies on Metal Organic Frameworks for solar applications, Perovskites, and 2D materials. Jens has more than a decade of experience in developing novel THz spectrometers and authored two tutorials on THz spectroscopy as well as more than 50 original papers on THz spectroscopy and emerging solar materials.
Tutorial PM3: Multiscale Characterization of PV Degradation and Performance Limitations
Instructor:
Harvey Guthrey, National Renewable Energy Laboratory, USA
Steve Johnston, National Renewable Energy Laboratory, USA
DescriptionMitigation of the various issues related to compromised performance of photovoltaic (PV) modules and devices requires in-depth understanding of the root cause. Performance issues are typically identified through device or module level observables such as open circuit voltage (VOC), short circuit current (JSC), or fill factor. However, the root causes are often due to features at the micron or sub-micron scale. Thus, connecting compromised PV parameters with the root causes of decreased performance requires a multi-scale multi-technique characterization approach to identify the structure, chemistry, and optoelectronic properties of the responsible features. This tutorial has two goals: (1) to present a summary of analysis techniques relevant to multi-scale PV characterization including measurement theory and practical information such as limitations and sample requirements and (2) to present a variety of case studies demonstrating how a multi-scale multi-technique characterization approach can be used to identify the root causes of compromised performance from the module level (imaging techniques) all the way to the sub-micron scale (electron-beam and scanning probe techniques) across a variety of PV material systems. The tutorial will begin with the technique descriptions including but not limited to PL, EL, DLIT, UVF, DLTS, EDS, EBIC, CL, TEM, and SIMS followed by case studies of issues relevant to state-of-the-art silicon, CdTe, CIGS, and hybrid perovskite modules and devices.
Dr. Harvey Guthrey is currently a research scientist in the Analytical Microscopy and Imaging Group at the National Renewable Energy Laboratory in Golden, Colorado. He received his Bachelor of Science in Physics from the University of North Texas and his PhD in Materials Science from the Colorado School of Mines in 2013. His research is primarily focused on applying electron microscopy-based characterization techniques to photovoltaic materials. His interests are CL, EBIC, FIB, EELS, STEM, and in-situ measurements. The overarching theme of his research is to gain better understanding of how the structural and chemical properties of photovoltaic materials can be altered to achieve higher efficiency devices through correlative characterization.
Steve Johnston is a senior scientist on the Microscopy and Imaging team of the Materials Science center of NREL. He received his B.S. in Engineering from the Colorado School of Mines (CSM); M.S. from the University of Illinois, Urbana-Champaign, in Electrical Engineering; and Ph.D. from CSM in Materials Science. He worked for more than two years at Texas Instruments with clean-room semiconductor processing and measurement equipment. He has experience with NREL in solar cell and solar materials characterization. His research interests include electroluminescence imaging, photoluminescence imaging, and lock-in thermography for material and cell characterization; deep-level transient spectroscopy for defect level identification; transient photoconductive decay for minority-carrier lifetime measurement; and ultra-short-pulse laser work for solar cell processing and micromachining applications.
Tutorial PM4: Grid Integration
Instructor: Nelson Leonardo Díaz Aldana, Universidad Distrital Francisco José de Caldas, Columbia
Description
One of the more essential requirements for the integration of PV into the electrical system is the power conversion stage which will be responsible for conditioning and coupling the PV generator to the power grid or the load. The tutorial will be focused on explaining the operation of the power conversion stages responsible for ensuring proper grid integration of PV generators.
The tutorial will begin by describing the main requirements for the interconnection of PV generation plants to grid-connected and/or islanded power grids by making and special insight into the desired operation of the power conversion stage. A review of power conversion topologies will be presented followed by the construction of simple simulation models of PV generators and their power conversion stages.
The simulation models will be built in MATLAB Simulink and they will be accompanied by the design and testing of simple control loops that ensure the reliable operation of the integrated PV generation Unit. In the end, it is expected that the attendees can derive their own simulation models to be used in research or academic projects.
Dr. Nelson Leonardo Díaz Aldana is an Associate Professor in Power Electronics and Microgrids at Universidad Distrital Francisco José de Caldas. He received his degree as Electronics Engineer from the same University and his master’s degree in industrial Automation from Universidad de Colombia. In 2017 received his Ph.D. degree in Energy Technology at Aalborg University in Denmark. He currently leads the Research Laboratory in Renewable Energy Sources at Universidad Distrital where he also teaches courses related to the integration of energy sources through power electronics conversion stages at undergraduate and graduate levels.
Tutorial PM5: Cost & Technology Trends Analysis: PV Supply Chains & PV Systems Coupled with Storage
Instructors:
Michael Woodhouse, National Renewable Energy Laboratory, USA
David Feldman, National Renewable Energy Laboratory, USA
Vignesh Ramasamy, National Renewable Energy Laboratory, USA
Brittany Smith, National Renewable Energy Laboratory, USA
Description
This tutorial will highlight the most recent efforts from the National Renewable Energy Laboratory (NREL) to track solar photovoltaic (PV) technology trends and manufacturing costs, project levelized cost of electricity (LCOE), and project levelized cost of solar plus storage (LCOSS) for systems across the globe.
We will begin with an overview of the global PV supply chain and 2021 benchmark input data for NREL’s crystalline silicon (c-Si) and thin film PV module manufacturing cost models. The framework that we follow and will review during this tutorial provides a methodology to prepare bottom-up manufacturing cost models including the items within the U.S. Generally Accepted Accounting Principles (GAAP) and the International Financial Reporting Standards (IFRS). For the polysilicon, wafer, cell conversion, and module assembly steps of the c-Si supply chain, and for thin film modules, we will review input data and methods useful for calculating the costs of goods sold (COGS); research and development (R&D) expenses; and sales, general, and business administration (S, G, &A) expenses. This 2021 benchmark analysis is compiled for state-of-the-art c-Si and thin film module manufacturing.
We will also review methods for our 2021 system benchmark costs calculations and LCOE technoeconomic analysis of PV systems and solar plus storage systems. Next generation technologies that lower PV manufacturing and installation costs, reduce operations and maintenance (O&M) expenses, and improve system energy yield will also be highlighted. Techniques for comparing LCOE performance will also be reviewed. We look forward to sharing NREL's extensive work in these areas and discussing ideas for future directions.
Michael Woodhouse is a senior analyst and the co-principal investigator with Robert Margolis for NREL’s solar and storage technoeconomic analysis portfolio, which currently includes work in designing and developing bottom-up manufacturing cost modelling software, conducting PV system levelized cost of electricity (LCOE) and levelized cost of solar plus storage (LCOSS) calculations, tracking current global solar and storage policy issues, and identifying research and development priorities for an accelerated global transition to clean and sustainable energy. Dr. Woodhouse also serves as the Associate Editor for Energy Economics and Policy for the Journal of Renewable and Sustainable Energy and on the Steering Committee for the International Technology Roadmap for Photovoltaics (ITRPV).
David Feldman has over 15 years of experience in the energy and financial industries. Currently he is a Senior Financial Analyst for the National Renewable Energy Laboratory (NREL), helping the organization carry out a wide range of analytical activities related to financial, policy and market developments in the solar industry. David has published and presented widely on topics related to renewable energy project finance, PV system and component modeling, public capital in the renewable energy sector, innovative financial models, and solar market development. Before working for NREL, David was the Assistant Director of Finance for Soltage, a developer and owner/operator of solar power projects. David graduated with an MBA from the Yale School of Management, with a focus in finance, and Amherst College with a BA in philosophy.
Vignesh Ramasamy is a member of the Distributed Systems and Storage Group in the Integrated Applications Center at National Renewable Energy Laboratory and he has 5+ years of experience conducting techno-economic analysis of PV and Energy Storage applications. At NREL his primary focus is on building and validating the system cost models for different technologies.
Brittany Smith is a solar techno-economic analyst at the National Renewable Energy Laboratory (NREL). Her areas of expertise are photovoltaic manufacturing supply chains, techno-economic analysis, and life cycle assessment. Her past work includes engineering and light management in III-V photovoltaic devices. She is currently serving as the Area 11 chair for PVSC-49, and holds a B.A. in Chemistry from the University of Delaware and Ph.D. in sustainability from the Rochester Institute of Technology.