Physical Sciences and Mathematics Commons^™

Wind For Schools: Fostering The Human Talent Supply Chain For A 20% Wind Energy Future, Ian Baring-Gould

Publications (E)

As the United States dramatically expands wind energy deployment, the industry is challenged with developing a skilled workforce and addressing public resistance. Wind Powering America’s Wind for Schools project addresses these issues by:
• Developing Wind Application Centers (WACs) at universities; WAC students assist in implementing school wind turbines and participate in wind courses
• Installing small wind turbines at community “host” schools
• Implementing teacher training with interactive curricula at each host school.

Correlations Of Capacitance-Voltage Hysteresis With Thin-Film Cdte Solar Cell Performance During Accelerated Lifetime Testing, David S. Albin, Joseph A. Del Cueto

Publications (E)

In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 ºC.

Effect Of Hysteresis On Measurements Of Thin-Film Cell Performance, David S. Albin, Joseph A. Del Cueto

Publications (E)

Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (V_oc), up to 10 mV, and smaller short-circuit current density (J_sc), by up to 2 mA/cm², relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be …

Use Of 2nd And 3rd Level Correlation Analysis For Studying Degradation In Polycrystalline Thin-Film Solar Cells, David S. Albin, Joseph A. Del Cueto, S. H. Demtsu, S. Bansal

Publications (E)

The correlation of stress-induced changes in the performance of laboratory-made CdTe solar cells with various 2^nd and 3^rd level metrics is discussed. The overall behavior of aggregated data showing how cell efficiency changes as a function of open-circuit voltage (V_oc), shortcircuit current density (J_sc), and fill factor (FF) is explained using a two-diode, PSpice model in which degradation is simulated by systematically changing model parameters. FF shows the highest correlation with performance during stress, and is subsequently shown to be most affected by shunt resistance, recombination and in some cases voltage-dependent collection. Large decreases …

High Efficiency, Low Cost Solar Cells Manufactured Using ‘Silicon Ink’ On Thin Crystalline Silicon Wafers October 2009 - November 2010, Homer Antoniadis

Publications (E)

The objectives of Phase I (Feb – Oct 2009) include the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Sil-icon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to …

Hybrid Cooling Systems For Low-Temperature Geothermal Power Production, Andrea Ashwood, Desikan Bharathan

Publications (E)

The overall objective of this investigation is to identify and evaluate methods by which the net power output of an air-cooled geothermal power plant can be enhanced during hot ambient conditions using minimal amounts of water.

Geothermal power plants that use air-cooled heat rejection systems experience a decrease in power production during hot periods of the day. This decrease in power output typically coincides with the time when utilities need power to address high air conditioning loads. Hybrid cooling options, which use both air and water, have been studied for this report to assess how they might mitigate the net …

The Silver Spark For Nevada, Walt Borland, James A. Croce, Richard Seline

Publications (E)

The SILVER Spark for Nevada: Sustainable Innovation Leading a Vital Economic Renaissance

Nevada. A State of stark contrasts, with historic booms and devastating busts experienced throughout its modern history. A State frequently forced to reinvent itself as ever-evolving circumstances have demanded. A State that has been driven to the edge time after time and, yet again and again, has managed to discover another way to prosper. A State that now finds itself in a precarious position as the “Great Recession” hit it harder than any other and has left it struggling to recover.

As you will conclude by reading The …

Creep In Photovoltaic Modules: Examining The Stability Of Polymeric Materials And Components, David C. Miller, Michael D. Kempe, Stephen H. Glick, Sarah R. Kurtz

Publications (E)

Interest in renewable energy has motivated the implementation of new polymeric materials in photovoltaic modules. Some of these are non-cross-linked thermoplastics, in which there is a potential for new behaviors to occur, including phase transformation and visco-elastic flow. Differential scanning calorimetry and rheometry data were obtained and then combined with existing site-specific time-temperature information in a theoretical analysis to estimate the displacement expected to occur during module service life. The analysis identified that, depending on the installation location, module configuration and/or mounting configuration, some of the thermoplastics are expected to undergo unacceptable physical displacement. While the examples here focus on …

Accelerated Stress Testing Of Hydrocarbon-Based Encapsulants For Medium-Concentration Cpv Applications, M. D. Kempe, T. J. Moricone, M. Kilkenny, J. Z. Zhang

Publications (E)

Concentrating photovoltaic (CPV) systems have great potential to reduce photovoltaic (PV) electricity costs because of the relatively low cost of optical components as compared to PV cells. A transparent polymeric material is used to optically couple the PV cell to optical components and is thus exposed to the concentrated light source at elevated temperatures. In this work polymeric encapsulant materials are positioned close to a Xenon arc lamp to expose them to ultraviolet radiation (UV) that is about 42 times as intense as sunlight. Furthermore, different glass types are used as filters to modify the spectral distribution of light in …

Impacts Of Mid-Level Biofuel Content In Gasoline On Sidi Engine-Out And Tailpipe Particulate Matter Emissions, Xin He, John C. Ireland, Bradley T. Zigler, Matthew A. Ratcliff, Keith E. Knoll, Teresa L. Alleman, John T. Tester

Publications (E)

In this work, the influences of ethanol and iso-butanol blended with gasoline on engine-out and post three-way catalyst (TWC) particle size distribution and number concentration were studied using a General Motors (GM) 2.0L turbocharged spark ignition direct injection (SIDI) engine. The engine was operated using the production engine control unit (ECU) with a dynamometer controlling the engine speed and the accelerator pedal position controlling the engine load. A TSI Fast Mobility Particle Sizer (FMPS) spectrometer was used to measure the particle size distribution in the range from 5.6 to 560 nm with a sampling rate of 1 Hz. U.S. federal …

Considerations For How To Rate Cpv, Sarah R. Kurtz, Matthew Muller, Bill Marion, Keith Emery, Robert Mcconnell, Sandheep Surendran, Adrianne Kimber

Publications (E)

The concentrator photovoltaic (CPV) industry is introducing multiple products into the marketplace, but, as yet, the community has not embraced a unified method for assessing a nameplate rating. The choices of whether to use 850, 900, or 1000 W/m² for the direct-normal irradiance and whether to link the rating to ambient or cell temperature will affect how CPV modules are rated and compared with other technologies. This paper explores the qualitative and quantitative ramifications of these choices using data from two multi-junction CPV modules and two flat-plate modules.

"Buried-Anode" Technology Leads To Advanced Lithium Batteries, National Renewable Energy Laboratory

Publications (E)

A technology developed at the National Renewable Energy Laboratory has sparked a start-up company that has attracted funding from the Advanced Projects Research Agency-Energy (ARPA-E). Planar Energy, Inc. has licensed NREL's "buried-anode" technology and put it to work in solid-state lithium batteries. The company claims its large-format batteries can achieve triple the performance of today's lithium-ion batteries at half the cost, and if so, they could provide a significant boost to the emerging market for electric and plug-in hybrid vehicles.

Outdoor Pv Degradation Comparison, Dirk C. Jordan, R. M. Smith, C. R. Osterwald, E. Gelak, Sarah R. Kurtz

Publications (E)

As photovoltaic (PV) penetration of the power grid increases, it becomes vital to know how decreased power output may affect cost over time. In order to predict power delivery, the decline or degradation rates must be determined accurately. At the Performance and Energy Rating Testbed (PERT) at the Outdoor Test Facility (OTF) at the National Renewable Energy Laboratory (NREL) more than 40 modules from more than 10 different manufacturers were compared for their long-term outdoor stability. Because it can accommodate a large variety of modules in a limited footprint the PERT system is ideally suited to compare modules side-by-side under …

Measuring Degradation Rates Without Irradiance Data, Steve Pulver, Daniel Cormode, Alex Cronin, Dirk C. Jordan, Ryan Smith, Sarah R. Kurtz

Publications (E)

A method to report PV system degradation rates without using irradiance data is demonstrated. First, a set of relative degradation rates are determined by comparing daily AC final yields from a group of PV systems relative to the average final yield of all the PV systems. Then, the difference between relative and absolute degradation rates is found from a statistical analysis. This approach is verified by comparing to methods that utilize irradiance data. This approach is significant because PV systems are often deployed without irradiance sensors, so the analysis method described here may enable measurements of degradation using data that …

Quantifying The Thermal Fatigue Of Cpv Modules, Nick Bosco, Sarah R. Kurtz

Publications (E)

A method is presented to quantify thermal fatigue in the CPV die-attach from meteorological data. A comparative study between cities demonstrates a significant difference in the accumulated damage. These differences are most sensitive to the number of larger (ΔT) thermal cycles experienced for a location. High frequency data (<1/min) may be required to most accurately employ this method.

U.S. Department Of Energy Commercial Reference Building Models Of The National Building Stock, Michael Deru, Kristin Field, Daniel Studer, Kyle Benne, Brent Griffith, Paul Torcellini, Bing Liu, Mark Halverson, Dave Winiarski, Michael Rosenberg, Mehry Yazdanian, Joe Huang, Drury Crawley

Publications (E)

The U.S. Department of Energy (DOE) Building Technologies Program has set the aggressive goal of producing marketable net-zero energy buildings by 2025. This goal will require collaboration between the DOE laboratories and the building industry. We developed standard or reference energy models for the most common commercial buildings to serve as starting points for energy efficiency research. These models represent fairly realistic buildings and typical construction practices. Fifteen commercial building types and one multifamily residential building were determined by consensus between DOE, the National Renewable Energy Laboratory, Pacific Northwest National Laboratory, and Lawrence Berkeley National Laboratory, and represent approximately two-thirds …

Wind Powering America Initiative: The Wind And Water Power Program (Wwpp), Energy Efficiency & Renewable Energy Information Center

Publications (E)

The U.S. Department of Energy's Wind Powering America initiative engages in technology market acceptance, barrier reduction, and technology deployment support activities. This fact sheet outlines ways in which the Wind Powering America team works to reduce barriers to appropriate wind energy deployment, primarily by focusing on six program areas: workforce development, communications and outreach, stakeholder analysis and resource assessment, wind technology technical support, wind power for Native Americans, and federal sector support and collaboration.

Solar Powering Your Community: A Guide For Local Governments, National Renewable Energy Laboratory

Publications (E)

The U.S. Department of Energy (DOE) designed this guide "Solar Powering Your Community: A Guide for Local Governments" to assist local government officials and stakeholders in designing and implementing strategic local solar plans. The 2011 edition contains the most recent lessons and successes from the 25 Solar America Cities and other communities promoting solar energy. Because DOE recognizes that there is no one path to solar market development, this guide introduces a range of policy and program options that can help a community build a local solar infrastructure.

State Of The States 2010: The Role Of Policy In Clean Energy Market Transformation, Elizabeth Doris, Rachel Gelman

Publications (E)

This report builds on the emerging body of literature seeking to identify quantitative connections between clean energy policy and renewable energy. The methods presented test the relationships between a broad set of policies and clean energy resources (energy efficiency, biomass, geothermal, solar, and wind). Energy efficiency findings are an initial foray into this type of analysis and indicate significant connections between reduced energy use and buildings codes, energy efficiency resource standards (in some cases), and electricity price. Renewable energy findings specify that there is most often a relationship between state policies and solar and wind development, indicating that while policies …

Guide To Community Solar: Utility, Private, And Non-Profit Project Development, Jason Coughlin, Jennifer Grove, Linda Irvine, Janet F. Jacobs, Sarah Johnson Phillips, Leslie Moynihan, Joseph Wiedman

Publications (E)

This guide is designed as a resource for those who want to develop community solar projects, from community organizers or solar energy advocates to government officials or utility managers.

Using Renewable Energy Purchases To Achieve Institutional Carbon Goals: A Review Of Current Practices And Considerations, Lori Bird, Jenny Sumner

Publications (E)

With organizations and individuals increasingly interested in accounting for their carbon emissions, greater attention is being placed on how to account for the benefits of various carbon mitigation actions available to consumers and businesses. Generally, organizations can address their own carbon emissions through energy efficiency, fuel switching, on-site renewable energy systems, renewable energy purchased from utilities or in the form of renewable energy certificates (RECs), and carbon offsets. This paper explores the role of green power and carbon offsets in carbon footprinting and the distinctions between the two products. It reviews how leading greenhouse gas (GHG) reporting programs treat green …

Economic Analysis Of A Brackish Water Photovoltaic-Operated (Bwro-Pv) Desalination System, Ali Al-Karaghouli, Lawrence L. Kazmerski

Publications (E)

The photovoltaic (PV)-powered reverse-osmosis (RO) desalination system is considered one of the most promising technologies in producing fresh water from both brackish and sea water, especially for small systems located in remote areas. We analyze the economic viability of a small PV-operated RO system with a capacity of 5 m³/day used to desalinate brackish water of 4000 ppm total dissolve solids, which is proposed to be installed in a remote area of the Babylon governorate in the middle of Iraq; this area possesses excellent insolation throughout the year. Our analysis predicts very good economic and environmental benefits of …

User's Guide To Mbc3: Multi-Blade Coordinate Transformation Code For 3-Bladed Wind Turbine, G. S. Bir

Publications (E)

The dynamics of wind turbine rotor blades are conventionally expressed in rotating frames attached to the individual blades. The tower-nacelle subsystem though, sees the combined effect of all rotor blades, not the individual blades. Also, the rotor responds as a whole to excitations such as aerodynamic gusts, control inputs, and tower-nacelle motion—all of which occur in a nonrotating frame. Multi-blade coordinate transformation (MBC) helps integrate the dynamics of individual blades and express them in a fixed (nonrotating) frame. MBC involves two steps: transforming the rotating degrees of freedom and transforming the equations of motion. Reference 1 details the MBC operation. …

Green Power Marketing In The United States: A Status Report (2009 Data), Lori Bird, Jenny Sumner

Publications (E)

This report documents green power marketing activities and trends in the United States. Aggregate green power sales data for all voluntary purchase markets across the United States are presented for 2009. The data presented in this report are based primarily on figures provided to NREL by utilities and independent renewable energy marketers. Because data cannot be obtained from all market participants, the estimates presented here likely represent an underestimate of the market size. Key trends identified in this year’s report include:
• In 2009, total retail sales of renewable energy in voluntary markets exceeded 30 million MWh, an increase of …

Further Developments On The Geothermal System Scoping Model, Mark Antkowiak, Rosemary Sargent, Jesse W. Geiger

Publications (E)

The fields of well construction and engineering, power plant construction and engineering, and reservoir engineering often proceed independently of one another. Yet the subsystems of a geothermal plant with which each of these fields is concerned need to be integrated in order to create a viable geothermal power system and make enhanced (or engineered) geothermal systems (EGS) a technical and an economic reality. Furthermore, each of these subsystems need to be examined in the context of the overall power system to aid with plant construction, and–more salient to the U.S. Department of Energy–to help determine best investment of research dollars. …

Photovoltaics (Pv) As An Eligible Measure In Residential Pace Programs: Benefits And Challenges, Jason Coughlin

Publications (E)

Property Assessed Clean Energy (PACE) financing is one of several new financial models broadening access to clean energy by addressing the barrier of initial capital cost. The majority of the PACE programs in the market today include PV as an eligible measure. PV appeals to homeowners as a way to reduce utility bills, self-generate sustainable power, increase energy independence and demonstrate a commitment to the environment. If substantial state incentives for PV exist, PV projects can be economic under PACE, especially when partnered with good net metering policies. At the same time, PV is expensive relative to other eligible measures …

Examination Of The Regional Supply And Demand Balance For Renewable Electricity In The United States Through 2015: Projecting From 2009 Through 2015 (Revised), Lori Bird, David Hurlbut, Pearl Donohoo, Karlynn Cory, Claire Kreycik

Publications (E)

This report examines the balance between the demand and supply of new renewable electricity in the United States on a regional basis through 2015. It expands on a 2007 NREL study (Swezey et al. 2007) that assessed the supply and demand balance on a national basis. As with the earlier study, this analysis relies on estimates of renewable energy supplies compared to demand for renewable energy generation needed to meet existing state renewable portfolio standard (RPS) policies in 28 states, as well as demand by consumers who voluntarily purchase renewable energy. However, it does not address demand by utilities that …

Wind Energy Workforce Development: A Roadmap To A Sustainable Wind Industry, Ian Baring-Gould, Marguerite Kelly

Publications (E)

As the United States moves toward greatly expanded wind energy use, the need for skilled workers at all industry levels has been repeatedly identified as a critical issue. Additionally, if the industry and nation wish to capitalize on this rapid industry growth by becoming a major international green technology exporter, reversing current educational trends away from science, engineering, and technical skills must be achieved.

This poster provides an overview of the educational infrastructure and expected industry needs through a discussion of the activities to train workers while addressing issues for each of the education sectors, leading to the development of …

Voluntary Green Power Market Forecast Through 2015, Lori Bird, Ed Holt, Jenny Sumner, Claire Kreycik

Publications (E)

Voluntary markets for renewable energy in which consumers purchase renewable energy from their electricity providers or from renewable energy certificate (REC) marketers have existed for more than a decade. Going forward, various factors will influence the development of these markets, including potential climate policies, state and federal renewable portfolio standards (RPS), renewable energy prices, the level of consumer interest in purchasing green power, and the interest on the part of utilities in offering new green options and in continuing to promote existing programs.

This report presents estimates of voluntary market demand for renewable energy or green power through 2015. The …

Solar Power And The Electric Grid, Energy Analysis, Nrel Energy Analysis

Publications (E)

In today’s electricity generation system, different resources make different contributions to the electricity grid. This fact sheet illustrates the roles of distributed and centralized renewable energy technologies, particularly solar power, and how they will contribute to the future electricity system. The advantages of a diversified mix of power generation systems are highlighted.