Reducing the Cost of Energy from Parabolic Trough Solar Power Plants: Preprint

Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. However, no new plants have been built during the past ten years because the cost of power from these plants is more expensive than power from conventional fossil fuel power plants. This paper reviews the current cost of energy and the potential for reducing the cost of energy from parabolic trough solar power plant technology based on the latest technological advancements and projected improvements from industry and sponsored R&D. The paper also looks at the impact of project financing and incentives on the cost of energy. INTRODUCTION This paper provides an assessment of the cost of power for parabolic trough solar power technology for large-scale gridconnected power applications, for both near-term and future parabolic trough solar power plants. The development and operation of the SEGS plants by Luz International Ltd. – totaling 354 MWe net installed capacity – provide a firm initial basis for future performance and cost projections. All are still in operation, best represented by the five 30-MWe plants operated by KJC Operating Co. at Kramer Junction, California. The Luz group failed in 1991, but technology development in the United States continued in the 1990s [1, 2]. The cost of energy can be reduced through technology improvements, scale-up in individual plant MW capacity, increased deployment rates, competitive pressures, use of thermal storage, and advancements in O&M methods. The cost of energy can also be reduced through lower cost financing and David Kearney Kearney & Associates P.O. Box 2568, Vashon, WA, 98070 [email protected] through taxation or investment incentives. The United States and European parabolic trough industries have developed proprietary plans for lowering costs in future trough power plants. The evaluation given here provides a cost estimate that generally agrees with industry expectations for R&D advances in component and subsystem improvements. METHODOLOGY This paper draws upon known data from technology improvements, R&D plans, and expected gains to project both reductions in investment costs and increases in performance. These data have been utilized in an NREL-developed model for evaluating the performance and economics of parabolic trough power plants, the primary metric being the levelized cost of electricity [3]. The model includes an hourly performance simulation module, a capital cost module, an O&M cost module, and a project-financing module. The performance module has been validated against the actual performance at the SEGS plants. For this study, the model predicted the annual gross solar-to-electric performance of SEGS VI during 1999 within 1% when using actual solar field availabilities, collector receiver conditions, mirror reflectivity and site solar radiation data. The capital cost module is in part based on detailed cost data from Flabeg Solar International [4]. The O&M cost module is based in part on data from KJC Operating Company. The project finance module is a 30-year cash flow model for evaluating independent power producer (IPP) power plant projects. The evaluation reported here also draws from a recent study [5] that examines the cost expectations for near-term, mid-term, and long-term trough power plants, generally covering the time frames of 2004, 2010, and 2020.