The
7th Arab Conference on Solar Energy & The Regional World Renewable
Energy Congress — Sharjah, UAE, 19-22 February 2001
“INNOVATIVE
HIGH-PERFORMANCE CONCENTRATOR PV SYSTEM FOR GRID-CONNECTED APPLICATIONS”
V. GARBOUSHIAN, D. HOFT, D. ROUBIDEAUX
Amonix,
Inc., 3425 Fujita Street, Torrance, CA, USA
90505
A
highly modular (5 kw — 25 kw) cost-effective Fresnel lens high-concentration PV
system is now available for immediate deployment. This state-of-the-art system represents the first technology for
large-scale multi-megawatt use of high-concentrator PV in the world. The system is based on an innovative
integrated structure called a MegaModuleÔ
that combines the structural components for aligning the Fresnel lens with the
concentration solar cell in a highly cost-effective manner. The system has completed large-scale
field-testing in severe geoclimate zones and is optimized for long-term 20-year
reliability and low maintenance. The
heart of the system is a high-performance back-contact high-concentration solar
cell that has established world records for sunlight-to-electricity energy
conversion efficiency combined with volume production. High-concentration PV directly attacks the
principle cost-driver of most PV systems, the solar cell, by significantly
(250X – 400X) reducing the amount of solar cell material needed to generate
electricity. The MegaModuleÔ system also
offers significant potential for in-country manufacturing.
KEYWORDS:
GRID-CONNECTED,
LARGE, UTILITY-SCALE, FRESNEL, MEGAMODULE, HIGH-CONCENTRATION, CONCENTRATOR
Amonix, Inc. of
Torrance, California has completed development of an innovative highly modular,
high-performance photovoltaic system based on its patented high-concentration
technology for large-scale, multi-megawatt installations around the world.
BACKGROUND
— “Why Concentrator?” — Cost effectiveness is a critical factor for mainstream
acceptance of solar energy generation.
For the cost-driven terrestrial markets, the industry's design focus has
been to reduce the principal cost “culprit” of the PV system: the silicon solar
cell. All approaches strive to reduce
the solar cell material content. One
trend in the PV industry is to pursue low cost by reducing the material
thickness (thin-film amorphous silicon).
Other approaches include development of alternate thin-film solar cells
using ‘exotic’ materials.
Amonix
pursued a highly cost-effective approach by reducing the area of costly cell
material required to generate a given amount of electricity. Using a low-cost intermediary Fresnel lens
to focus and concentrate sunlight onto a specially designed, high-performance
small area solar cell (1 cm2), we have been successful in reducing
the required silicon cell area by over 250 times with our Integrated
High-Concentration Photovoltaic (IHCPV) system design.
Although
the high-concentration photovoltaic concept had been theoretically studied for
many years, it was not considered commercially practical because of the lack of
a solar cell capable of withstanding the environment generated by highly
concentrated sunlight. Amonix was able
to successfully bring its extensive semiconductor technical background to bear
on the key element of the IHCPV system -
the solar cell.
Key features of the high-concentration
technology include:
Ø
High performance, concentration photovoltaic silicon
solar cells that received the ‘R&D 100 Award’ for technical achievement.
o
This solar cell is the ‘heart’ of our IHCPV
system and contributes to the very high total system AC efficiency of 16% plus
o
Concentrating PV technologies directly attack
the principal cost driver of any PV system — the costly solar cell — by
reducing the amount of solar cell material required to generate a given amount
of electricity by a factor equal to the concentration ratio — in our case, 250
times less solar cell material required
o
This inherent cost reduction factor translates
into tremendous potential for cost reduction at multi-megawatt levels of
production. The system is already very
cost competitive at modest levels of production; projections to 25 — 50
megawatts indicate a significant advantage over competing technologies
Ø
Integrated High-Concentration PV (IHCPV)
receiver plate producing 110+ wattsAC at rated concentration
(PVUSA). Each MegaModuleÔ houses 48 of
these receiver plates and produces 5 kilowatts.
Ø
Highly modular Fresnel lens integrated modules
(MegaModuleÔ)
operating at approximately 250X concentration.
Ø
A new patented hydraulic tracking drive with
custom tracking controller capable of handling large arrays in winds up to 100
miles per hour. When the system detects
winds exceeding 100 miles per hour, the system is programmed to drive itself
into safety stow.
With its built-in tracking, the system’s energy
production factor is significantly higher than that of fixed flat-plate PV
systems. This advanced system is the
culmination of over six years of ‘hands-on’ field-testing and product
refinement in severe geoclimate zones such as the desert areas of the
Southwestern United States. In
partnership with several of the nation’s largest utility providers, 100 kW of grid-connected
evaluation and demonstration systems were deployed in five different geoclimate
zones for long-term (four year) performance evaluation. All of the ‘lessons learned’ from these test
installations were incorporated into the new, patented MegaModuleÔ system
configuration (Figure 1). The Company
has begun full-scale production of commercial MegaModuleÔ systems with
plans to produce greater than one megawatt next year.
Each array produces 5 kilowattsDC per MegaModuleÔ at PVUSA test
conditions[1]
(the preferred commercial rating for utility scale systems). Configurations are flexible from 5
kilowatts (1 MegaModuleÔ)
to 25 kilowatts (5 MegaModulesÔ)
depending on customer requirements.
Proprietary software, especially developed for
the IHCPV system, is used in order to ensure the most efficient utilization of
land and the solar resource. This
software optimizes the physical layout of a particular site location for such
factors as size, shape, elevation and shading.
This software, coupled with Amonix’s field experience, helps to assure
the maximum potential of each installation.
Figure 1:
A four MegaModuleÔ System produces 20,000 watts
Each aspect of the system has been matched to meet
the requirements of large-scale, grid-connected customers.
Ø
All 48-receiver plates in each MegaModule are
electrically combined in-series to generate as high a voltage as possible per
MegaModule. This high voltage allows
the use of higher efficiency inverters used to convert the DC power generated
by the IHCPV system into AC for grid connection.
Ø
All components are designed for 20+ year life in
harsh geographic locations. The entire
system has been subjected to rigorous field-testing and evaluation to ensure
trouble-free operation.
Ø
Because of its optimized thermal coefficient,
the IHCPV system can be passively cooled, that is it needs no external source
for cooling such as water. This is
especially significant for remote, desert installations where water cooling
represents a life-cycle risk.
Ø
The standalone computer based tracking system
has the capability to interface with line or wireless modem to allow remote
control of a large field of IHCPV systems from a central base. In addition, instantaneous data such as
temperature, power output, and solar resources can be remotely monitored.
General field layout and installation of
tracking drive
|
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Lift and mounting of MegaModulesÔ
