TerraSmart Deploys the First and Largest Solar Farm on U.S. Tribal Lands
Tribal members of the Moapa Band of Paiutes have fought for years to shutter an aging coal-burning plant adjacent to their reservation in Nevada. Coal ash from the facility, they say, pollutes their land and has caused a sharp rise in diagnoses of asthma and other related ailments.
For this Native American community turning to solar energy to replace a share of the coal generating capacity simply made sense; it was just a matter of finding the right solar partner. With its track-record of building complex ground mount systems on tight schedules, TerraSmart was the best choice for the project.
TerraSmart combined installation expertise with design, engineering and manufacturing capabilities to offer the Moapa Band of Paiutes a complete turnkey solution. The 353-megawatt system used TerraSmart’s surveying, drilling, ground screw and proprietary fixed-tilt mounting to support over 3.2 million modules on roughly 2,000 acres in this landmark Clark County project.
But the installation had its challenges. The Moapa Valley is a prehistoric flood plain famous for its sandstone rock formations — wonderful sightseeing but difficult for solar.
Moapa Valley’s soil required TerraSmart to resolve critical obstacles on-site quickly: its top layer is made up of one to two feet of hard caliche soil, a rock-like mixture of sand and limestone which is tough to penetrate. Eight to 12 inches of light sand lie just below the rocky top layer, creating issues for typical driven piles.
Because speed was a critical component to the project’s success, the TerraSmart team brought a number of proprietary solutions to the site. First 128,000 TerraSmart ground screws were used to penetrate the caliche layer of rock quickly, providing an accelerated foundation for the modules’ fixed-tilt racks.
Then TerraSmart engineers swiftly developed proprietary software to overcome challenges in surveying and drilling in loose soil. This software loaded the rock-drill machines with coordinates to locate foundation points precisely, allowing proper pile location without damaging sacred Paiute lands.
The soil combination in Moapa Valley would have caused unacceptable delays for most racking companies. Traditional drill and survey methods would not have assured the stability or accuracy in the caliche rock and loose sandy layer.
The Moapa Band of Paiutes already knew from the get-go they were in good hands with TerraSmart. But they did not anticipate the team’s high degree of respect for the tribal lands. Not only did TerraSmart experts overcome numerous construction challenges on the spot, they did so while striving to minimize environmental impacts and protect surrounding sacred sites.
Now the tribe is reversing its use of fossil fuels and related air pollution by generating enough clean solar energy to displace approximately 178,000 metric tons of carbon dioxide (CO2) annually.
But the forward-thinking leaders of the Moapa Band of Paiutes will not stop here. The tribe plans to develop up to 1.5 gigawatts of solar power on their 70,000-acre reservation, dedicating their lands to the production of clean energy for generations to come. And TerraSmart stands ready to help them reach that goal.
Location: Moapa, NV – Located on the Moapa Indian Reservation
Status: Completed August 2016
DC System Size: 353 Megawatts
Type of Rack: Fixed-Tilt Ground Mount
# of Ground Screws: 128,000
# Modules: 3,209,091
Module Manufacturer: First Solar
– Design Specifications –
Wind Load: 90
Snow Load: 10
Exposure Category: C
Tilt Angle: 20 degree tilt
Distance from Grade: Embedment depth of screw, 4 ft.
Soil Type: Caliche
Awarded 2016 Utility-Scale Project of the Year
Our work, creating the first utility-scale project on U.S. tribal lands with Moapa Southern Paiute Solar, has been awarded Solar Builder’s 2016 Project of the Year as a testament to the value of partnerships and TerraSmart’s unique ability to triumph over challenges.
Read the full story on page 30-31 in Solar Builder magazine.