Solar Energy Bruce Logue and Robert Chou The University of Texas at Austin Department of Chemical Engineering Fall

Overview How Solar Energy Works Types of Photovoltaic Systems –Flat-plate and Concentrator Current Applications Solar Economics –Price Trends –Costs –The Energy Payback Time Advances in Technology –Thin-film –PV roofing panels –Nanomaterials

How does solar energy work? The Photoelectric effect The PV cell layered with positive and negative charged semiconductor material 2 3

Photovoltaic Systems System is constructed of Arrays There are two types of systems –Flat Plate Systems System can be in a fixed position or moving Makes use of Direct and Diffuse sun light –Concentrator Systems Moves relative to the sun Requires less PV cell material 4 5 6

Current Applications

Solar Energy Economics The cost of PV cells has been on decline since 70’s. Decline due to advancements in efficiency and manufacturing techniques Residential equipment costs can range from 10K to 100K 13 14

Energy Payback Time (EPBT) EPBT is length of time PV system takes to generate amount of energy put into system. Three factors determine the EPBT: –Amount of illumination received by PV cells –Conversion efficiency of PV cell –Manufacturing technology used to make PV cell

Manufacturing Methods There are three methods to produce PV cells –Process cells on wafers sawed from silicon ingots Ingots are either single or multicrystalline –Process cells on silicon wafers cut from multicrystalline ribbons –Deposition of non-crystalline silicon on inexpensive substrates Single- crystal silicon Non-ribbon multicrystalline silicon Ribbon Multicrystalline silicon Cheap Substrate (Cadmium Telluride) EPBT (Years)

Technological Advances Thin-Film Technology –PV cells are continually processed on a sheet consisting of much less material than the typical PV cells. Copper Solar Cells –Thin-Film PV cells are made with Cu to increase efficiencies greater than 12% compared to silicon 16 17

Technological Advances Solar Roof Panels –Shingles are combined with PV cells creating insulation that generates electricity Nanomaterials –Solar cells incorporating nanomaterials are stronger, more flexible, and more efficient

References Fast Solar Energy Facts. 14 Nov Harlin, Kevin. "Building new power panels." The Times Union. LexisNexis Academic. LexisNexis. 20 Nov Konarka, Textronic to Develop Solar Thin-fil PV Fabric. (2005, September 29). Renewable Energy Access. Retrieved November 19, 2006, from "Nanomaterials and Cost-effective Manufacturing Technologies Hold Key to Development of Photovoltaic Technologies." PR Newswire US. LexisNexis Academic. LexisNexis. 20 Nov PV Markets. 20 Nov Recent Advancements in Solar Panel Technology by Shell Solar. 20 Nov Residential Solar Power Costs & Savings. 15 Nov Solar Energy Technologies Program. (2006,April 13). Retrieved November 10, 2006, from U.S. Department of Energy Web site:

Images Images Courtesy of  1 –  2 –       8 –  9 –   11 –    Energy_Course/energy/Renewables/pv/French_site/overview.html      19-