Commercial Grid-Direct Floatovoltaics System: Far Niente Winery

The Far Niente Winery PV system presented a variety of unique design, permit and installation challenges. SPG Solar was tasked with zeroing out the client’s electric bill by fitting as much PV as possible onto an existing gray water treatment pond and a triangular lot, both about one acre each.

Mounting solutions from Thompson Technology Industries (TTI) optimized the available areas. A TTI Floatovoltaics system, a mounting platform for PV installations on bodies of water, was used atop the treatment pond. For the array on land, SPG Solar used TTI’s Adjustable- Tilt Ground Mount.

Anchoring the Floatovoltaics system to counter wind uplift and a fluctuating water level while maintaining orientation and providing maintenance access presented design challenges. The existing aerators required rearranging. A wastewater engineer helped SPG Solar prove that the system would not degrade the health of the pond.

An existing PG&E utility transformer was upgraded to accommodate the inverter’s nameplate kVA. This upgrade allows for future facility growth at the winery. The new primary required access through a neighbor’s property via a utility easement and permission from the California Department of Fish and Game to cross a small stream. Step-up and -down 480 V to 4,160 V transformers and an existing spare conduit were used to transmit the power 3,500 feet. Meteorologic and PV monitoring data is wirelessly transmitted the same distance using repeaters.

"An added benefit from the Floatovoltaics system is that the shade it creates lowers the pond’s biological oxygen demand by diminishing UV, temperature and algae growth. This reduces the time the aerators are on and therefore their energy use."

Dan Berger, SPG Solar

Overview

DESIGNER: Dan Berger, senior project designer, SPG Solar, spgsolar.com
LEAD INSTALLER: Mike Ewers, installation foreman, SPG Solar
DATE COMMISSIONED: May 2008
LOCATION: Oakville, CA, 38.4° N
SOLAR RESOURCE: 5.56 kWh/m2/day
RECORD LOW/AVERAGE HIGH TEMPERATURE: 23°F / 89°F
ARRAY CAPACITY: 478 kW STC
AVERAGE ANNUAL AC PRODUCTION: 618,272 kWh

Equipment Specifications

MODULES: 2,296 Sharp ND-208U1, 208 W STC, +10%/-5%, 7.3 Imp, 28.5 Vmp, 8.13 Isc, 36.1 Voc
INVERTERS: 3-phase, 480 Vac system, 1 Satcon Power Gate AE-500- 60-PV-A, 500 kW, 600 Vdc maximum input, 295–600 Vdc MPPT range
ARRAY: 14 modules per circuit (2,912 W, 7.3 Imp, 399.0 Vmp, 8.13 Isc, 505.4 Voc), 164 circuits total (477,568 W, 1,197.2 Imp, 399.0 Vmp, 1,333.32 Isc, 505.4 Voc)
ARRAY COMBINERS: 21 Thompson Technology Industries (TTI) String Watch combiner boxes (19 @ 8 circuits, 1 @ 7 circuits, 1 @ 5 circuits) with 7 Square D HU363 100 A, 600 Vdc heavy duty safety switches
SYSTEM MONITORING: Proprietary TTI SunSpot monitoring system with interactive kiosk
ARRAY INSTALLATION: TTI Floatovoltaics pontoon mount (206.7 kW subarray) and TTI Adjustable-Tilt Ground Mount (270.8 kW subarray); 180° azimuth, 20° tilt

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