By Mike Rosso
High on a ridgetop south of Salida sits the possible future of solar energy generation.
In May 2010 the SolFocus Concentrator Photovoltaic (CPV) system, the first of its kind in Colorado, began generating electricity from the sun on property owned by Salidans Michael and Joyce Ferree.
Michael Ferree is the Vice President of Operations for Cate Street Capital, a private equity firm specializing in the financing of sustainable energy technologies. He purchased an old ranch property south of Salida in 1999 where he now has his home and office, and decided to try a pilot project employing the CPV system, one which had not yet been attempted at high altitude nor in winter conditions.
The system employs two CPV arrays which covert sunlight to electricity at about twice the efficiency levels of other photovoltaic (PV) technologies. This is due to a special design incorporating a unique parabolic optical system that focuses a large area of sunlight onto individual PV cells, magnifying it nearly 650 times. Combined, the two arrays create 16.8 kilowatts of direct current (DC) power with the capacity of generating 50 megawatt-hours annually – power enough for six average homes.
Ferree hired local contractors from Salida and Coaldale to do everything from excavation and installation to computer programming. The project took about three months to complete, which included road and civil construction. The system is going though rigorous testing due to the high winds on the ridgetop, as well as winter conditions that have yet been experienced with the new technology. Nearly 120 tons of cement were used to “overbuild” the platforms due to the high wind speeds anticipated at the site.
Initially two of the panels overloaded due to the increased solar gain – a result of the altitude and cleaner air found at the site. Basically too much of a good thing. The SolFocus engineers then modified the panels to increase their capacity.
Ferree reported that the panels performed “perfectly” when the mercury plummeted to -20 degrees on Feb. 3.
The panels are computer-controlled, programmed to track with the sun and to go “flat” at night through the use of a dual-axis (tilt and rotate) system. The DC current generated by the panels travels through underground cables to an inverter, which converts it to alternating current (AC) for residential use.
Ferree took advantage of rebates from the Xcel Energy Solar Rewards program (see sidebar, next page) as well as state and federal tax credits. In combination they offset nearly 60% of the capital cost in the first year.
On a large monitor in his office at the ranch, Ferree can track the performance and output of the system at any given time and is able to display graphs showing the current as well as month-by-month output. The system has yet to experience a heavy snowfall, which will be a test as to whether the panels will withstand snowpack and continue to operate efficiently, he said.
Also in the works by SolFocus is a two-mode energy system using pipes to circulate water on the backside of the panels as a hot water supplement in addition to the solar electric cells.
The California-based manufacturer, SolFocus, was founded in 2005 and currently has its concentrator photovoltaics in California, Arizona, Hawaii, Spain, Mexico and Salida. The panels are manufactured using recyclable, non-toxic materials which consist of primarily glass, aluminum and steel.
Ferree also informed us in late-February that Cate Street Capital had just announced a joint venture with SolFocus and Moraine Partners LLC at their MorStarch manufacturing facility in Monte Vista, CO. The 502.7 kW-DC solar energy facility will include 57 SF-1100S CPV arrays occupying approximately three acres of land next to the MorStarch facility, and is expected to offset approximately 100% of MorStarch’s current Xcel Energy load. The solar power plant will be constructed and placed in operation later this year.
