Solar Thermal Electricity Dan Recht Photovoltaic electricity faces challenges Cost Scale Storage Ian Britton: http://www.freefoto.com/preview/04-12-14?ffid=04-12-14 NASA/GSFC: http://www.flickr.com/photos/wwworks/2712986388/ Tracey Olson: http://www.flickr.com/photos/tracy_olson/61056391/sizes/l/in/photostream/ Heat can come from many sources Fossil Fuels Biomass The Sun Also: nuclear, geothermal, chemical, etc. Left to Right: Ian Britton http://www.freefoto.com/preview/13-25-7?ffid=13-25-7&k=Coal Pat Schmitz http://en.wikipedia.org/wiki/Image:Miscanthus_giganteus.jpg Arun Kulshreshtha http://commons.wikimedia.org/wiki/File:The_Sun.jpg Water heaters can use sunlight as fuel Adapted from Inkwina http://commons.wikimedia.org/wiki/File:Thermal-solar.svg Stan Zurek http://en.wikipedia.org/wiki/File:Solar_panels,_Santorini.jpg Most power plants rely on steam turbines Electricity Heat Adapted from: Andrew Ainsworth http://en.wikipedia.org/wiki/File:Rankine_cycle_layout.png Concentrated sunlight can boil water Dave Gough: http://www.flickr.com/photos/ Parabolic mirrors concentrate sunlight Andrew Buck: http://en.wikipedia.org/wiki/File:Parabolic_trough.svg Concentrators must track the sun Adapted from: Solar Millennium Blythe Application for Certification http://www.energy.ca.gov/sitingcases/solar_millennium_blythe/documents/applicant/afc/index.php Geometry limits concentration rays from left rays from right edge of sun edge of sun (exactly on axis) (0.5° off axis) Only direct sunlight can be concentrated NREL Best Practices Handbook for the Collection and Use of Solar Resource Data