STIRLING CONCENTRATOR SETS SOLAR RECORD AT SANDIA

Stirling Energy Systems (SES) has power purchase agreements with two major Southern California utilities (Southern California Edison and San Diego Gas & Electric) for 1,750 megawatts of power, the world’s two largest solar power contracts. These PPAs will require 70,000 SES units.

SES has been working with Sandia National Labs for years to perfect its units. This new level of performance may move development forward. Bruce Osborn, president/CEO, SES: “This exciting record shows that using these dishes will be a cost-effective and environmentally friendly way of producing power…SES is actively engaged in the commercialization of the system, called the ‘SunCatcher,’ including continuing to prepare it for mass production, completing project site development and preconstruction activities, and establishing partnerships with substantial manufacturing and industrial organizations to develop a cost-effective manufacturing process and supply chain…”

Sounds like Southern California is about to get 2 huge new solar thermal installations.

The unit generates electricity by focusing the sun’s rays onto a receiver, which transmits the heat energy to a Stirling engine, a sealed system filled with hydrogen. The hydrogen heats, pressure rises and drives pistons. The mechanical power of the pistons drives a generator that produces electricity.

Osborn: The demonstrated high efficiency means more energy is generated for the given investment, lowering the cost of the energy delivered.”

Key factor in the record setting performance: It was a perfect day. Bright sun and cool air. Not many days like that in Southern California, where if the sun shines it is hot.

The Stirling unit. (click to enlarge)

Sandia, Stirling Energy Systems Set New World Record for Solar-to-Grid Conversion Efficiency
February 13, 2008 (Newswise)

WHO
Stirling Energy Systems (SES) (Bruce Osborn, president/CEO); Sandia National Laboratories (Chuck Andraka, lead project engineer)

WHAT
The SES solar dish “Serial #3” collector has set a new record for converting sunlight to electricity, upping the energy delivered to the grid from the solar energy hitting the dish from 29.4% to 31.25%.

Osborn and his record-setting units. (click to enlarge)

WHEN
- The previous record had stood since 1984.
- The new record was set January 31.
- The Serial #3 dish was erected in May 2005 as part of a prototype 6-dish system that daily produces 150 kilowatts.
- The test ran for 2 and ½ hours and the record was based on a 60 minute average.
- SES was formed in 1996.

WHERE
- The new record was set at the Sandia test center in Albuquerque, NM.
- SES is based in Phoenix, AZ, and has facilities in Tustin, CA.

Sandia's Andraka (left) being interviewed. (click to enlarge)

WHY
- Each Serial #3 has 82 mirrors.
- SES owns the dishes and hardware.
- Sandia provides technical support and analysis.
- Efficiency is calculated by dividing the amount of energy delivered to the grid by the amount of energy hitting the dish.
- Most important advancement: improved optics from (1) low iron glass with silver backing making the mirrors highly reflective, putting 94% of sunlight to engine (up from 91% on earlier models) and (2) more accurate mirror facets with fewer imperfections. These optics allow a beam only 7 inches in diameter to be focused on the receptor.
- Improvements to the engine system: (1) cheaper, more effective radiator and (2) higher efficiency generator.
- 26.75 kW of electricity were generated during testing.

Artist's concept: An array of Stirling units. (click to enlarge)

QUOTES
- Osborn, SES: “Gaining two whole points of conversion efficiency in this type of system is phenomenal…This is a significant advancement that takes our dish engine systems well beyond the capacities of any other solar dish collectors and one step closer to commercializing an affordable system.”
- Andraka, Sandia: “It was a ‘perfect storm’ of sorts…We set the record on Jan. 31, a very cold and extremely bright day, a day eight percent brighter than normal.”