PHOTON International The Photovoltaic Magazine

Solar trough installation for APS could affect PV commitment

With the March 24 start of construction on a solar trough installation for Arizona Public Service (APS), the Arizona utility could be moving away from PV to meet its targets for solar-electricity generation in the state.

	© Arizona Public Service Company
Competition coming: The single-axis and Amonix trackers at APS's Prescott site could lose their shine as the Arizona utility starts construction on a 1 MW solar trough installation nearby.

North Carolina-based SolarGenix Energy LLC won the contract two years ago, back when the company was Duke Solar. The 1 MW system will include 40 parabolic trough solar collectors for powering an Organic Rankine Cycle (ORC) turbine. Completion of the remotely monitored and operated system at APS's Saguaro Power Plant, located 50 km north of Tucson, is slated for April 2005.

»If it works successfully, we may install more of these,« says Peter Johnston, manager of technology development at APS. »I suppose that could be at the expense of PV.« APS, which has been putting in around 1 MW of PV annually, has about 4.5 MW of installed PV.

Johnston says the first SolarGenix installation is contracted at a cost of $6 per W, a figure expected to come down to $4 for future installations. But the decision to continue with solar thermal depends on the operating and maintenance costs, he adds. SolarGenix has a goal of less than 3¢ per kWh. »While that is a challenge,« says Johnston, »SolarGenix believes they can do it.«

Arizona's Corporation Commission (ACC), which passed a renewable portfolio standard in 2001 (see PI 3/2001, p. 20), requires all of the state's investor-owned utilities to generate 1.1 percent of their energy through renewable sources – 60 percent through solar – by 2007. Johnston, who admits that APS is not meeting its requirements, notes that ACC has started a series of workshops, which he thinks may increase the percentage targets by mid-2004.