Smud celebrates 20 years of solar power dedicates expansion of one of the world’s first solar plants

SACRAMENTO, August 27, 2004 — The Sacramento Municipal Utility District (SMUD) celebrated the 20th anniversary of one of its first major solar installations, PV1, with the dedication of new solar arrays at the site, PV6. The new installation, increases generation from the solar plant to 3.2 megawatts (MW), enough to power more than 2,200 single-family homes. Twenty years ago, PV1 generated one MW, powering about 700 typical homes.

SMUD PV1, built in 1984, was one of the first in the world and continues to perform extremely well by industry standards, operating at about 80 percent of original performance. The plant has grown over the past two decades and with the dedication of the sixth installation, the plant now has more than 5,000 solar panels. Most of the panels are mounted on trackers that follow the sun across the sky maximizing the capture of solar energy and conversion to electricity. Nearby, the cooling towers of the closed Rancho Seco nuclear site can be seen and the construction sounds of SMUD’s 500 MW gas-fired power plant can be heard.

Engineers at the Southwest Technology Development Institute of Las Cruces, New Mexico did testing on PV1. The test involved acquisition of IV curves on all 56 half-source circuits of the array. For redundancy, the DC output was verified by using the product of measured string current times array voltage. These two methods resulted in values that agree within 1.2%. The 1 MW Omnion inverter efficiency was measured at 95%. The average measured performance degradation of 18.5% over 20 years is considered excellent by industry standards.

PV1 occupies 10 acres and includes 28,672 Arco M52-N modules in a single axis-tracking configuration. The modules are assembled into 896 panels that are aligned north to south. At sunrise, the trackers align the panels at a 45-degree angle to the east. The trackers follow the sun across the sky from 3 hours before solar noon until 3 hours afterward, making a 3-degree movement every 12 minutes. The panels convert solar energy directly into electricity.

SMUD continues to be a leader in the renewable energy arena. In the last year, 9% of SMUD’s energy deliveries came from renewables, excluding hydropower generation from plants larger than 30 MW. SMUD has committed to increase the renewables portion of deliveries to 10% by 2006 and to 20% by 2011. In addition, about one quarter of SMUD’s energy comes from hydropower generation plants over 30 MW in size.

SMUD leads all utilities in the United States with more than 8.3 MW of installed solar on area buildings, homes, parking structures and in open fields such as PV1-6. In recent years, SMUD has expanded its program from large-scale arrays to customer-owned solar energy systems atop homes and businesses, or integrated in building materials.

The PV1 system has generated approximately 31.3 GWh of electrical energy, offsetting
emissions of 16 million pounds of CO2, 5,000 lbs. of SO2, and 14,000 lbs. NOx, equal to approximately 1,200 cars being removed from the road. For more information about SMUD’s solar programs and vision, please visit

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The Clarion Energy Content Team is made up of editors from various publications, including POWERGRID International, Power Engineering, Renewable Energy World, Hydro Review, Smart Energy International, and Power Engineering International. Contact the content lead for this publication at

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