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Making kilowatts while the sun shines

Article by Mike Rosso

Energy – December 2008 – Colorado Central Magazine

“Drill, baby, Drill”?

Residents of Central Colorado have taken a different tact regarding the energy issues confronting them in the 21st century by choosing to take advantage of a renewable resource found in abundance in our region: Sunshine.

Today, voters statewide can see the direct results of initiatives they passed in 2004 that required utility companies to begin using alternative energy sources. Now three sun-powered projects are currently up and running in the region. These demonstration projects, one in the San Luis Valley and two in Chaffee County, employ electricity-generating solar power.

The initiatives

In November of 2004 Colorado voters passed Amendment 37, the Renewable Energy Requirement. The initiative required the state’s largest utility providers to obtain three percent of their electricity from renewable energy resources by the year 2007 and 10 percent by 2015. It also established a standard net-metering system for homeowners and ranchers with small photovoltaic (PV) systems to connect to the power grid. In addition, the measure called for four percent of the mandated amount of renewable energy to come from solar (sun-powered) resources, the goal being to help wean consumers from fossil fuels by employing local power production.

Despite repeated rejection of alternative energy legislation by Colorado lawmakers and strong resistance by electric utility companies, the measure was successful when brought to a public vote. And in 2007 Governor Bill Ritter signed two additional bills into law; Colorado House Bill 1281 and Senate Bill 100.

HB 1281 raised the standard for electricity generation from eligible energy sources for investor-owned utilities, effectively doubling the RPS (renewable energy portfolio) to 20 percent by the year 2020. It also expanded the definition of a “qualifying retail utility” to include all utilities, except municipally owned utilities serving less than 40,000 customers, and “eligible energy sources” to include recycled energy.

SB 100, Transmission for Energy Resource Zones, will allow utilities to locate and map energy resource development areas, in order to plan and file for approval to build transmission (delivery) systems.

Photovoltaics, anyone?

According to the NASA website, “photovoltaics is the direct conversion of light into electricity at the atomic level.” Some materials have a property known as the photoelectric effect that makes them absorb photons of light and release electrons. When those free electrons are captured, the resulting current can be used for electricity.

PV cells or “solar cells” are made of semiconductor materials, such as silicon. The cells consist of “a thin semiconductor wafer [that’s] specially treated to form an electric field, positive on one side and negative on the other. When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current.” Multiple PV cells make up a module and multiple modules are wired together to form an array. It is these arrays which are the basis of the systems described here.

The SunEdison Photovoltaic Plant near Alamosa

The U.S. Department of Energy has identified the San Luis Valley as having the best solar power conditions in Colorado.

Drive south along State Highway 17 and it’s hard to miss the UFO viewing platform near Hooper. It’s even harder to miss the vast array of flat panels that appear to be growing out of the parched landscape farther south.

In December of 2007, SunEdison, North America’s largest solar energy service provider, activated the most extensive solar PV plant in the United States. Located on approximately 80 acres north of Alamosa in the San Luis Valley, it supports substation loads for a major public utility.

The 8.22-megawatt plant was financed and built by SunEdison under a long-term Solar Power Services Agreement whereas Xcel Energy, one of Colorado’s largest utility suppliers, will buy renewable energy credits and the solar power generated by the plant for 20 years to help meet Colorado’s renewable portfolio standards.

The plant generates approximately 17,000 megawatt hours annually, enough wattage to power 1,500 homes. The system employs three types of solar tracking technologies and Xcel is studying the system’s performance to evaluate the benefits of each technology over the system’s expected 20-year lifespan.

Chaffee County Fairgrounds

In Chaffee County, two PV projects of note have been launched since the passage of Amendment 37, one at the County Fairgrounds and another at the Sangre De Cristo Electric Association in Buena Vista.

The fairgrounds project was conceived by the county commissioners to meet state standards for public buildings, according to Chaffee County Commissioner Jerry Mallett, who initiated the public demonstration project.

In early 2008 a Request for Proposal for a subcontractor was put out by the county. The bid was awarded to Peak Solar Designs of Salida and installation of the system began on May 1. The process required a special- use permit and zoning approval from the town of Poncha Springs, as well as public input.

By Memorial Day the ground-mounted structure was in place and functioning. The system consists of forty-eight 205-watt silicon-based PV panels which generate an annual output of 14,908 AC kilowatt hours (kWh) per year. That’s enough to power about 20 percent of the fairgrounds’ electric needs according to Tim Klco, owner of Peak Solar Designs. The carbon offset is estimated to be equivalent to driving an average passenger car 33,356 miles annually, he said.

Three inverters were also installed to convert the system’s DC output to AC and balance the three-phase electrical service at the fairgrounds. The system is tied to the fairground’s electrical service, and all of the excess electricity produced goes back into the power grid on a 1:1 net meter ratio. In other words, excess electricity generated by the solar system is credited by Xcel to the fairgrounds on an equal input and output ratio, said Klco.

The total cost of the system including hardware, installation, and labor was $74,000, with Xcel Energy paying $44,280 of the final cost. The county paid the balance. Nearly 60 percent of the cost of this system is being paid with tax credits and rebates, according to Klco.

The Sangre De Cristo Electric Co-op

The Sangre De Cristo Electric Association (SDCEA) in Buena Vista applied for two matching-grant pilot programs offered by the Colorado Governor’s Energy Office (GEO) and was chosen for both the Small Residential Wind and Residential Solar PV Rebate programs. In addition, SDCEA also installed its own Small Wind Turbine and residential-sized Solar PV demonstration systems, according to Bill Bennett, Energy Use Advisor for the electric co-op.

As a non-profit organization, the co-op is not eligible for federal tax credits, but was selected by the GEO for two $25,000 matching grants that allowed the co-op to offer rebate programs to its members for both Small Wind and Residential Solar PV. The matching grant rebate money is available only for members who are full-time residents and meet eight required steps as outlined in SDCEA’s rebate plan (see web links below).

For its own PV demo project, the co-op also advertised a Request for Proposal awarding Peak Solar Design’s bid for a 3.34 kW DC grid-tie Solar PV system, comparable to an average residential system. The system is ground mounted, allowing for seasonal adjustment of the panels to maximize output which is expected to be approximately 5,092 kWh annually. A similar wind turbine demonstration project was completed last year, and both sit in front of the SDCEA headquarters building in Buena Vista. In addition, realtime and historical data is available on the co-op’s website for both systems.

SDCEA has also been involved with state, federal, academic, and private organizations, and the Co-op Research Network (CRN) in researching the possibility of electric power generation from geothermal resources within Chaffee County and surrounding areas. SDCEA is also working to establish a Small Hydro Working group, in an attempt to foster power generation from hydro resources in the region. Because of its proactive work in alternative energies, SDCEA has become a highly valued partner with the Colorado Governor’s Energy Office.

To date, SDCEA has seven members participating in the Solar PV Rebate Program and one member participating in the Small Wind Rebate Program. According to Bennett, the governor’s office may expand its matching grant programs to include small businesses in its next phase of announcements.

Further information on both of these rebate programs is available on the web at:



Mike Rosso is a webmaster, photographer, and writer based in Salida.