Energy
- 641
 - National Renewable Energy Laboratory: Photovoltaic Research
 - U.S. Department of Energy. Research and development, and information source on photovoltaics. Website includes a virtual library of online reference materials and photographs on photovoltaic technology, educational materials, links to commercial suppliers and other web resources.
 
- 642
 - IOFFE: Photovoltaics Laboratory
 - Institute of photovoltaics of the Physico-Technical Institute (IOFFE) of Saint-Petersburg, Russia. Includes technical data and publications.
 
- 645
 - Pumped storage reservoirs
 - Energy Resources article uses Dinorwig as an example. Includes Introduction, How It Works, and More details about Dinorwig.
 
- 647
 - FERC: Taum Sauk Pumped Storage Project, Dam Breach Incident
 - Description (by Federal Energy Regulatory Commission) of impoundment failure. Link to press release, AmerenUE consultant's report, and photo gallery. (May 01, 2006)
 
- 648
 - Reservoir Break Causes Flood in Southern Missouri
 - Text summary with link to audio. All Things Considered [NPR] (December 15, 2005)
 
- 649
 - Clouds gather over solar pond technology
 - Indian newspaper article testifies that the Bhuj solar pond payback period worked to be less than five years, but operation stopped with closure of the customer industry.
 
- 650
 - Solar pond
 - Description, (dis)advantages, efficiency, development, and external links from Wikipedia, the free encyclopedia. User may contribute.
 
- 651
 - California Car Company Initiative
 - A non-profit group promoting "plug-in hybrids" - hybrid gas/electric cars that have larger batteries and can be recharged at an outlet.
 
- 652
 - Eltra Technology, Inc. Hybrid Electric Vehicle
 - Alternative fuel vehicle, this Hybrid Electric Vehicle from Eltra Tech is an electric car using true series hybrid drive system entered in the Progressive Automotive X-Prize Race.
 
- 653
 - Fueleconomy.gov
 - The Department of Energy's fuel economy site gives gas mileage tips, gas price info, and a tool to compare fuel efficiency of hybrids and conventional cars. The "Fuel Economy Guide" provides the government view on reasons to be concerned about fuel economy.
 
- 656
 - Hybrid Car Guide
 - Provides hybrid car information and industry news for the curious or the enthusiasts, plus a fuel savings calculator.
 
- 657
 - Hybridcars.com
 - Information about hybrid vehicles, with daily news, blogs, and interactive tools, including a link that allows users to compare hybrid and non-hybrid vehicles, for gas consumption and emissions.
 
- 658
 - Plug In America
 - Information on electric and hybrid car technology. Political policy updates and resources to contact various stakeholders in the industry.
 
