A few comments on photovoltaics (solar cells)

Updated 12/6/10

Solar Cells: one path to sustainable energy

. . . also called "photovoltaic" (PV) energy

. . . Some images:

http://inhabitat.com/wp-content/uploads/sunpower_main.jpg

http://www.greenfab.us/blog/wp-content/uploads/2009/02/solar-cells.jpg

http://www.scitoyscatalog.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=SOLARCELL&Category_Code=
http://keetsa.com/blog/science-and-technology/solar-power/solar-cells-run-off-like-printing/
http://blog.makezine.com/archive/2006/08/make_a_solar_cell_in_your.html
http://www.treehugger.com/files/2007/05/suntech_starts.php
http://www.metaefficient.com/architecture-and-building/skyscraper-gets-covered-in-7000-solar-panels.html

What is the future of PV, etc.?

. . . First, the "etc.":  http://blog.ted.com/2009/06/02/announcing_sing/

. . . Next, lets focus on the PV graph

. . . . . . curve fitting a straight line gives the slope

. . . . . . what is the slope? See hard copies

. . . . . . let's "Delphi it"!

Types of PV technology

. . . Example technological advance

. . . . . . Cost reduction approach: vacuum typically needed to deposit top layer of anti-reflective material, vacuum processing is expensive, spray-on technology is cheaper and under development

. . . . . . Thin film vs. regular

. . . Efficiency improvement (are these exponential?)

. . . . . . http://www.ijdesign.com/blog/Solar-Cell-Efficiency.jpg
. . . . . . http://www.allinsolars.com/images/Solar%20Cell%20Efficiency.gif
. . . . . . http://www.solarnavigator.net/images/pv_solar_module_efficiency_chart.jpg
. . . . . . http://www.tf.uni-kiel.de/matwis/amat/semi_en/kap_3/illustr/eta_development.gif


For general information on PV see: http://www.pveducation.org/pvcdrom


A major tipping point: grid parity

. . . check some graphs: see
. . . . . . image.google.com (query: grid parity)

Exercise: using a hard copy of Kurzweil's graph, figure out when PV will satisfy 100% of energy needs

. . . Assume world uses 15,000,000 (15 million) megawatts (per http://en.wikipedia.org/wiki/World_energy_resources_and_consumption)
. . . . . . Note: for simplicity, you may assume 10,000,000 if you wish

. . . Assume continued exponential growth
. . . . . . (straight line on log graph)

. . . Ok that's the mathematical result, but what do you think will really happen?
. . . . . . Why?