Scientific and Technical Aerospace Reports Volume 39 April 6, 2001

The National Renewable Energy Laboratory (NREL) installed two Advanced Research Turbines (ART) at the National Wind
Technology Center near Boulder, Colorado, to use as full-scale test beds for ongoing research efforts, including three-dimensional
blade aerodynamics and the effects of various control methods on turbine loads and performance. The Westinghouse WWG-0600
was selected as a baseline configuration for the ART turbines. The first turbine, ART-1, is currently operational and has been used
to collect a baseline set of performance and loads data. A second turbine, ART-2A, incorporates several major modifications and
may be upgraded further to a configuration designated aRT-2B. Possible features of the ART-2B turbine include a multi-degree
of freedom hum and newly designed rotor blades. Global energy concepts, L.L.C. provided engineering support to NREL in
designing the components for the ART-2B turbine. This document provides a summary of work performed by GEC on the aerodynamic
design of ART-2B rotor blades.
NTIS
Wind Turbines; Turbine Blades; Three Dimensional Flow; Aerodynamics
20010026206 Sandia National Labs., Albuquerque, NM USA
Energy Storage Systems Program Report for FY99
Boyes, J. D.; Jun. 01, 2000; 218p; In English
Report No.(s): DE00-759441; SAND2000-1317; No Copyright; Avail: Department of Energy Information Bridge
Sandia National Laboratories, New Mexico, conducts the Energy Storage Systems Program, which is sponsored by the US
Department of Energy’s Office of Power Technologies. The goal of this program is to develop cost-effective electric energy storage
systems for many high-value stationary applications in collaboration with academia and industry. Sandia National Laboratories
is responsible for the engineering analyses, contracted development, and testing of energy storage components and systems.
This report details the technical achievements realized during fiscal year 1999.
NTIS
Electric Energy Storage; Systems Analysis
20010026212 National Renewable Energy Lab., Golden, CO USA
Stable a-Si:H Based Multijunction Solar Cells with Guidance from Real Time Optics, Phase 1 Annual Report, 17 Jul. 1998
- 16 Oct. 1999
Wronski, C. R.; Collins, R. W.; Jiao, L.; Ferlauto, A.; Rovira, P. I.; Aug. 29, 2000; 159p; In English
Report No.(s): DE00-28809; NREL-SR-520-28809; No Copyright; Avail: Department of Energy Information Bridge, Microfiche
This summary describes tasks of novel improved intrinsic materials for multijunction solar cells, insights into improved stability
in materials and solar cells, optimization of solar cell performance with improved intrinsic layers, and optimization of multijunction
solar cells. The report characterizes a protocrystalline a-Si:H film growth regime where thin samples retain their
amorphous state when their growth time or thickness is limited to small values, even when films are deposited with high hydrogen
dilution that results in microcrystalline thick films. The Staebler-Wronski degradation kinetics of films and devices are systematically
studied as a function of hydrogen dilution.
NTIS
Stability; Amorphous Materials; Amorphous Silicon; Solar Cells
20010026213 National Renewable Energy Lab., Golden, CO USA
Thin-Film CIGS Photovoltaic Technology, Phase 2 Annual Report, 16 Apr. 1999 - 15 Apr. 2000
Delahoy, A. E.; Bruns, J.; Ruppert, A.; Akhtar, M.; Chen, L.; Aug. 24, 2000; 30p; In English
Report No.(s): DE00-28786; NREL/SR-510-28786; No Copyright; Avail: Department of Energy Information Bridge, Microfiche
A summary of Energy Photovoltaics Phase II work includes the following: (1) EPV has demonstrated that it can sputter a
Mo back-contact capable of supporting very high efficiency cell processing. Using EPV Mo, NREL has deposited a 17.1% CIGS
cell (no AR coating). EPV believes it can identify the signature of ’good’ Mo. The Mo was produced on EPV’s 0.43 m(sup 2)
pilot-line equipment; (2) EPV has performed compound synthesis for several classes of materials, namely non-Cu precursor materials,
Cu-containing materials, and ternary buffer materials. Using a ternary compound synthesized at EPV (ZIS) as an evaporation
source material for the buffer layer, a Cd-free CIGS device has been produced having an efficiency of 11.5% (560 mV, 32.1 mA/
cm(sup 2), FF 64.3%). The ZIS films are photoconductive, and the devices exhibit no dark-light crossover or light soaking effects;
(3) EPV initiated the interest of the University of Oregon in capacitance spectroscopy of CIGS devices. An Urbach tail with characteristic
energy E0 < 20meV was identified by transient photocapacitance spectroscopy; (4) Small-area CIGS devices were
produced in the pilot-line system with an efficiency of 12.0% (581 mV, 30.1 mA/cm(sup 2), FF 68.7%), and in an R and D-scale
system with 13.3% efficiency (569 mV, 34.1 mA/cm(sup 2), FF 68.1%); (5) An improved linear evaporation source for Cu delivery
has been developed and was used for CIGS formation in the pilot-line system. The deposition width is 45 cm. This technologi-
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