BrightSource Testing Heliostat Poles
June 25, 2010 - Ivanpah Valley, San Bernardino County, California.
The solar company seeking to develop almost 4,000 acres of public land in the eastern Mojave Desert has been running into a problem for months now: geology. The site negotiated for them with the Bureau of Land Management is an active flood-wash fan below Clark Mountain. Delivered straight from rocky peaks are countless cobbles and boulders buried in the fan soil deposits from untold millennia of outwash debris flows. Here BrightSource is proposing to build its massive central receiver ("power tower") solar thermal power plant, but it must drive thousands of poles 10 feet into the ground first to affix the mirrors that will reflect sun rays onto the tower receivers. Testing of different pole-driving methods has been ongoing at various times since last year. In 2009, pile-driving methods "failed miserable" according to the Bureau of Land Management (personal communication 2010). The latest method is using vibrations to work the poles into the rocky substrate.
The BLM issued a permit to test the installation of the "pipes" for the mirrors on a small area of public land for the Ivanpah Solar Electric Generating System.
BLM told us BrightSource is re-using a test site that they worked on a little over a year ago. Last year they were having very big problems driving the pipes in the ground so now they are "geotesting" another way, the vibration system. All environmental review for the tests was completed last year on the same site so no environmental assessment or categorical exclusion was needed this time. They did complete an Environmental Assessment on it last year. The site is 3.5 acres. BLM indicated that they are still having some problems driving the pipes in the ground.
The soil appears sandy, but the pipes often hit cobbles - which stop the pipes altogether or force the pipes off to one side.
^Apparent completed test site just north of Colosseum Road.
^Staging area. There is a substantial amount of equipment on Colosseum Road: six Cat tractors with treads and either shovels or pile drivers, a flatbed truck loaded with pipe, a trailer (serving as an office), a couple of semi's, and miscellaneous smaller vehicles.
^While we watched a new road was graded into the desert to a pole testing site in the creosote scrub.
^Staging area in the distance where heavy machinery sits while testing is undertaken. The Primm Valley Golf Course lies beyond, and Ivanpah Playa in the distance.
^Staging area with equipment.
^Heliostats turned upwards in "safety position" (as during winds) at Solar 2 in Daggett, California, before dismantling. The central receiver power tower stands over the mirrors.
Old Growth Desert
^One of many washes that frequently bring down cobbles and boulders from the mountains in flash floods.
^Backlit Buckhorn cholla (Cylindropuntia acanthocarpa) and creosote (Larrea tridentata).
^The project site at Ivanpah Valley where tens of thousands of heliostat poles would be driven into the desert soil to hold mirrors that would reflect sun rays onto central receiver power towers higher than the brown hill in the middle-distance.
^A small Pencil cholla (Cylindropuntia ramosissima) flower blooms.
^The Mojave yuccas (Yucca schidigera) have green pods now.
^Buckhorn cholla and Clark Mountain.