Wednesday, June 30, 2010

Xcel switches on hybrid solar-coal power plant - Minneapolis / St. Paul Business Journal

Xcel switches on hybrid solar-coal power plant - Minneapolis / St. Paul Business Journal

The mirrors focus the sun’s heat on a line of tubes filled with food-grade mineral oil. The oil is heated to about 575 degrees Fahrenheit, then the heat is transferred, heating water to about 360 degrees, according to Xcel.

The project includes eight rows of mirrors, 500 feet long, covering 6.4 acres, according to Xcel (NYSE: XEL).

The solar-heated water then is transferred to the 49-megawatt power plant’s existing coal-fired boiler, and heated to higher temperatures to produce the steam needed to spin turbine blades that generate electricity. Using solar-heated water cuts the amount of coal needed to produce steam, according to Xcel.

The combined, integrated use of solar power and coal is expected to increase the power plant’s efficiency by up to 5 percent, reduce the use of coal by 900 tons per year, and cut the plant’s carbon dioxide emissions by 2,000 tons per year.

20 Solar Cell Prototypes That Could Change the Future : TreeHugger

20 Solar Cell Prototypes That Could Change the Future : TreeHugger

algal_biofuels_roadmap.pdf BIOMASS PROGRAM this another form of Solar Energy

algal_biofuels_roadmap.pdf (application/pdf Object)

National Algal Biofuels Technology Roadmap
A technology roadmap resulting from the National Algal Biofuels Workshop
December 9-10, 2008
College Park, Maryland
Workshop and Roadmap sponsored by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Office of the Biomass Program
Publication Date: May 2010

17.6% efficiency flexible CIGS solar cell on plastic developed at EMPA - Photovoltaics World

17.6% efficiency flexible CIGS solar cell on plastic developed at EMPA - Photovoltaics World

17.6% efficiency flexible CIGS solar cell on plastic developed at EMPA
http://www.pennenergy.com/etc/medialib/platform-7/pvworld/industry-news.Par.95156.Image.250.171.1.gif

Figure 1: Independently certified measurement of a 17.6% efficiency flexible CIGS solar cell under standard test condition performed at ISE Friburg, Germany.
(June 30, 2010) -- Flexible thin film solar cells on polymer film with a new record efficiency of 17.6% have been developed by the scientists at the Swiss Federal Laboratories for Material Science and Technology (EMPA). The 17.6% photovoltaic conversion efficiency of the flexible solar cells has been independently certified by the Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg, Germany.
http://www.pennenergy.com/etc/medialib/platform-7/pvworld/industry-news.Par.82965.Image.250.235.1.gif
Figure 2: Quantum efficiency measurement of a 17.6% efficiency flexible CIGS solar cell under standard test condition performed at ISE Friburg, Germany.

Scientists under the leadership of Dr. Ayodhya N. Tiwari at the Laboratory of Thin Film and Photovoltaics, EMPA, Dübendorf, Switzerland (http://www.empa.ch/tfpv) have been developing thin film solar cells based on Cu(In,Ga)Se2 (CIGS) semiconductor material, and the research group, while working at ETH Zurich in 2005, had developed 14.1% efficiency flexible CIGS solar cells on polymer film. Now, collaborating with FLISOM Company (www.flisom.ch), the group's process results in a 17.6% efficiency solar cell.

Development of high efficiency solar cells on plastic film is challenging because most of the polymer films used as substrate lack thermal stability for growth of high electronic and structural quality CIGS solar cell layers at high temperatures. High thermal expansion coefficient (CTE) of polymer causes a large stress in the layers deposited at high substrate temperature resulting in cracks and delamination of the solar cells from the substrate. Doctoral student Adrian Chirila and colleagues, working under the supervision of Dr. Tiwari, have been developing a vacuum evaporation process for growth of high-quality CIGS absorber layers at sufficiently low temperature of about 450C that is suitable for polyimide film as a flexible substrate for roll-to-roll manufacturing.

A large improvement in the efficiency of flexible cell, from a previous record value of 14.1% to a new record of 17.6% was achieved by reducing the optical and electronic losses in the CIGS solar cell structure. The most important factor was the optimisation of the composition gradient of Ga across the CIGS layer thickness and an appropriate incorporation of Na for doping during the final stage of the growth process. Consequently, an optimum band gap grading and larger grain size in CIGS layer resulted in a substantial increase in the efficiency of flexible solar cells. The photovoltaic measurements performed under the standard test condition at ISE Friburg confirmed 17.6% efficiency with Voc = 688 mV, Isc = 34.8 mA/cm2, FF = 73.6%.


Figure 3: Scanning electron microscopic image of the cross-section of a typical CIGS solar cell. http://www.pennenergy.com/etc/medialib/platform-7/pvworld/industry-news.Par.41469.Image.200.172.1.gif
The low temperature process for CIGS deposition offers a unique advantage that the same process and equipment can be used for polymer as well as metal foils. Flexible CIGS solar cells on metal foils with highest efficiency of ca 17.5% are generally grown at high temperatures above 550°C, while lower efficiencies were obtained on polymer films because of lower deposition temperature. The successful development of 17.6% efficiency flexible CIGS solar cell on polymer with a low temperature process has closed the efficiency gap between the solar cells on polymer and metal foils. This solar cell processing can be adapted for roll-to-roll manufacturing of monolithically connected solar modules on polymer films. Lower thermal budget and roll-to-roll manufacturing of high efficiency flexible CIGS solar cells will pave the way for substantial reduction in production cost of next generation of solar modules produced on large industrial scale in future.
Figure 4: Image of flexible CIGS solar cells on lightweight polymer film.
Figure 4: Image of flexible CIGS solar cells on lightweight polymer film.

Preliminary results of the flexible CIGS solar cell development were presented at the recent IEEE Photovoltaic Specialist Conference, June 21-25, Honolulu, HI, where Adrian Chirila also received a Student Award for the development of high-efficiency flexible CIGS solar cells and monolithically connected solar modules developed in collaboration with FLISOM Company.

For more information, contact Prof. Dr. Ayodhya N. Tiwari, Head, Laboratory for Thin Films and Photovoltaics (Abt. 130), EMPA (Swiss Federal Laboratories for Material Science and Technology), Überlandstrasse 129, CH-8600 Dübendorf, Switzerland; +41-44-8234130 (Direct); ayodhya.tiwari@empa.ch; www.empa.ch/tfpv

Source:
Photovoltaics World

Tuesday, June 29, 2010

Solar Update - all the latest solar & PV news

"http://www.solarupdate.com/solar-pv-news.php">Solar Update - all the latest solar & PV news

MONITORING 27 SOLAR & PV NEWS SITES... http://www.solarupdate.com/solar-pv-news.php

Solar Industry Mag http://www.solarindustrymag.com/
PV Tech http://www.pv-tech.org/
IPVEA http://www.ipvea.com/
Renewable Energy World http://www.renewableenergyworld.com/
Solar Plaza http://www.solarplaza.com/
Renewable Energy Focus http://www.renewableenergyfocus.com/
Photovoltaik http://www.photovoltaik.eu/
Forbes Solar News http://www.forbes.com/
Thin Film Today http://social.thinfilmtoday.com/
Thin Film Today sen.jpg Solar Energy Directory
Build-It Solar Solar Energy Directory
Solveclimate Blog http://solveclimate.com/
Intersolar DE http://www.intersolar.de/
Global Solar Technology - Industry http://globalsolartechnology.com/
Global Solar Technology - Technology http://globalsolartechnology.com/
Global Solar Technology - Trade Shows http://globalsolartechnology.com/
Renewable Energy Magazine http://www.renewableenergymagazine.com/
Pv Society-Breaking http://www.pvsociety.com/
Science Daily http://www.sciencedaily.com/
Google Solar News http://news.google.com/
Google PV News http://news.google.com/
Google Solar Blogsearch http://blogsearch.google.com/
Google PV Blogsearch http://blogsearch.google.com/
CalFinder http://solar.calfinder.com/
Solar Energy News http://www.esolarenergynews.com/
Topix http://www.topix.com/
Solar Energy Directory http://solarenergydirectory.com/

Sacramento Solar Company Hopes to Achieve Cost Parity With Nuclear, Coal | Get Solar.com

Sacramento Solar Company Hopes to Achieve Cost Parity With Nuclear, Coal | Get Solar.com

That's on par with nuclear and coal,