The arrays consist of hundreds of convex glass mirrors precisely focusing the sun on smaller mirrors which direct the beam down towards the small PV cells PHOTO: M. Ferree

Concentrated solar refers to the use of mirrors and/or lenses to focus large amounts of light on a smaller area.   In the case of the SolFocus system, concave mirrors are used to concentrate sunlight onto small high efficiency solar cells, this magnification is approximately 500 times the normal amount of light, often referred to as “suns” (i.e. 500 suns).  Right now you are probably remembering those poor ants that you focused your magnifying glass on as a kid and wondering how the solar cells can take the heat.  These are no ordinary cells and are the heart of what sets this system apart. These patented cells are designed to take the high heat created from the 500 suns focused on them, but more importantly according to SolFocus, they allow a concentrated solar array to use approximately 1/1000th the photovoltaic material used in a conventional system. The photovoltaic material in a solar array is expensive, driving a major portion of the cost and is difficult to recycle. Because the majority of these concentrating arrays are glass and aluminum they have a much greater recyclable content than ordinary arrays and require less energy to build, further adding to their environmental friendliness.

Assembly of the major components required a large crew as well as a crane and was carried out on Earth Day. PHOTO: M. Ferree

Just as you learned during your childhood experiments (okay some of us still play with magnifying glasses in the sun) alignment of the focused beam is important.  Since the position of the sun is constantly changing throughout the day, concentrating solar arrays must move or “track” the sun across the sky. To accomplish this, the arrays are mounted on large poles and have computer controlled motors which slowly swing the arrays with the sun each day, keeping them aligned to within one degree of the sun as well as placing them into a protective horizontal position when extremely high winds are measured by the system’s anemometers.

As you can see from the images, these arrays are large and not typically installed for residential use.  They are designed for large commercial or industrial installations. This installation for a residence is unique and came about because Michael Ferree is Vice President of Project Management for Cate Street Capital, an investment firm with interest in SolFocus.  This particular installation will be used by Sol Focus to demonstrate the viability of their systems in our region and its performance will be measured against a more typical 9.66 kilowatt roof mounted photovoltaic system previously installed on the site by Peak Solar to power Ferree’s office building.
According to Tim Klco of Peak Solar, many area businesses and government facilities could benefit from these systems. Heart of the Rockies Regional Medical Center and Sangre De Cristo Electric have both shown interest in the system although neither has committed to the purchase.

Dave Beaulieu and Tim Klco of Peak Solar Designs affix an assembled array being supported by a crane to the large mounting pole. PHOTO: M. Ferree

This is the first system of it’s kind installed in Colorado, and a first for Salida based Peak Solar.  This installation really demonstrates how green energy can benefit rural communities like Salida.  Not only will fewer energy dollars be sent out of the valley during the lifespan of the installation (estimated to be more than 25 years), but the installation employed a lengthy list of local businesses and individuals;  Peak Solar Designs, G/T Structural Engineers, Kane Builders, Koch Excavating, Marv’s Electric of Salida, Shavano Custom Log Works (crane service), RAC Transport Company and Hard Rock Paving & Redi-mix.

Located just south of Salida in the San Luis Valley, this giant facility has been mystifying valley travelers since going online last year. SunEdison owns the Alamosa Photovoltaic Solar Plant and sells the power to Xcel Energy. The facility helps Xcel, the state’s largest utility, comply with Amendment 37 and the state’s new renewable energy standard. The standard, signed into law by Gov. Ritter in 2007, requires that utilities like Xcel obtain 20 percent of their electricity from renewable sources by 2020.

“With wind farms across the plains, new biodiesel and ethanol plants, the National Renewable Energy Lab, innovative businesses like SunEdison and Xcel Energy and this solar energy project, Colorado really is the renewable energy capital of the Nation,” says Senator Ken Salazar.

The National Renewable Energy Laboratory rates the San Luis Valley as having the best solar power conditions in Colorado. The plant creates enough clean energy to power nearly 1,500 homes a year operating at full capacity, which is unrealistic. In reality, the plant will power roughly 5000 homes based on average household energy needs. In addition, the plant generates enough clean energy to remove the carbon emissions produced by 2,840 cars driving 12,500 miles annually or roughly 710,000,000 miles over 20 years. Since going online in 2007, the boom has continued around the world, and already this plant is being dwarfed in size, capacity and efficiency by new facilities.

The solar power plant near the substation is unique in that it consists of three distinct types of solar technologies: single axis tracking array, fixed-mount array and dual axis tracking array. According to Karen Hyde, vice president of resource planning and acquisition at Xcel Energy, “This is a unique facility – three types of solar technologies have been deployed in parallel. Performance monitoring will allow us to study the system’s performance and evaluate the relative benefits of each technology over the system’s expected 20-year lifespan.”

A German partner is doing much of the monitoring and comparative studies. The system can be remotely-controlled from their offices in Germany. It’s truly amazing to watch these massive dual axis arrays, the largest in the world, make micro-movements to meet the optimum angle of sun and earth.

Building the solar power plant created about 50 temporary jobs in Alamosa and the San Luis Valley. Now, however, it is run by a small maintenance crew located in Alamosa. This may have been one of the most striking parts of the day; total silence. Unlike any other form of power generation, the plant sits silent. It quietly gathers power almost of its own volition.

Stepping back onto the big yellow dinosaur to leave was something that will likely be lost on my traveling companions when they are my age, but hopefully one day they will recall the black diesel smoke that was about to cloud the humble sun farmers’ domain. As I stepped back on the bus I took one more picture of almost 30,000 solar panels. Looking to the east, the sand dunes rose majestically to meet the mighty snow-capped Sangres, and other than the chatter of the low-rising tour group, all I could hear was the breeze. The smell was intoxicating however, it was the fresh scent of a new energy economy on the horizon.

Follow-up

If you go to the plant you will find literally no information, simply tall cyclone fences surrounding the facility. Through the excellent work of Samantha Lane and Carrie Gordina, two Salida Middle School 5th-grade teachers, the tour was assembled with only slight headaches and a few phone calls. Once inside, the lonely crew seemed sincerely thrilled to show off the facility. I would guess tours for groups will be more easily arranged in the future as the plant settles into routine operation. If anyone else has had another experience at the Alamosa SunEdison plant, please comment below. Thanks again to Samantha, Carrie and Dewey for your time, patience and excellent work putting this trip together. My youngest son, as well as the entire 5th grade, is better for it.

See also: Alamosa solar plant’s success helps prove resource’s viability on large scale (Denver Post)