Little Rock Test Facility

Little Rock was eSolar’s first testing ground. eSolar’s first heliostat field was installed and used to create the control software that evolved into Spectra.


eSolar’s first R&D site in Littlerock, CA

In 2007, the test site of 3000 heliostats and a small solar receiver on a tower in Littlerock, CA took our hardware out of the laboratory and into the real-word.  Our product could now be tested to withstand the harsh realities of the desert, and we could improve our designs to account for the effects of wind, dust, corrosion and extreme heat cycles.

Our control systems and targeting could also be tested at scale with thousands of our heliostats connected together for the first time.  We developed our patented calibration systems using cameras and pointing screens, and methods for testing our pointing accuracy. Metrics and criteria we could use to measure improvements in our systems as we moved forward could finally be defined. Our attention to detail allowed us to measure extremely small real-world errors intrinsic in every electric motor and gear system, and even measure the changes in metals as they heat up during the day. This knowledge allows us to account for the errors and variations, and plowed the way towards our current milliradian accuracy.

It was at Littlerock where the eSolar team first created steam from our Solar Collector System (SCS). We honed the technology required to generate separate sun-tracking data for each heliostat, and developing the “throttle” – a way of choosing which heliostats shine sun at the tower at any time.

eSolar's First Field mirror in tower DSC00378