Clean Edge and Nasdaq's three benchmark clean-tech stock indexes each had solid gains last week with the Nasdaq Clean Edge Green Energy Index (CELS) up 4.88%, the Nasdaq OMX Clean Edge Global Wind Energy Index (QWND) growing 4.14%, and the Nasdaq OMX Clean Edge Smart Grid Infrastructure Index (QGRD) 4.46% higher from the previous week.The overall market also had a positive week -- the S&P 500 gained 3.10%; Nasdaq added 3.94% and Amex Oil ended the week up 4.26%. CELS -- up 4.88% for the week and 76.18% higher than a year ago -- tracks U.S.-listed clean-energy companies and is divided into four categories: advanced materials; energy intelligence; energy storage and conversion; and renewable electricity generation and renewable fuels. In the advanced materials sector, all five component companies were in positive territory. Energy intelligence had 18 components up and two down. In energy storage and conversion, eight components were in positive territory and two lost ground. For renewable electricity and fuels, 14 components were up and one was down. CELS' best performer for the week was advanced composite material maker Hexcel ( HXL), gaining 16.06%. Rounding out the top five CELS performers were PV manufacturer Evergreen Solar ( ESLR), up 15.18%; solar cell and module maker Canadian Solar ( CSIQ), rising 12.60%; demand energy management firm Comverge ( COMV), gaining 12.37%; and electronic materials provider Rubicon Technology ( RBCN), up 12.29%. CELS' worst performer last week was solar manufacturing equipment provider GT Solar International ( SOLR), declining 0.94%. Other worst performers included energy storage product developer Maxwell Technologies ( MXWL), falling 4.47%; lithium-ion battery maker Valence Technology ( VLNC), losing 2.15%; semiconductor manufacturer IXYS ( IXYS), down 1.41%; and geothermal power developer Raser Technologies ( RZ), losing 0.94%. QWND -- up 4.14% last week and 32.65% higher in the last 12 months -- includes companies that are primarily manufacturers, developers, distributors, installers and users of energy derived from wind sources. Of QWND's 23 pure-play components, 20 saw gains last week while the remaining three lost ground. QWND's best pure-play performer for the week was India-based wind power company Suzlon Energy , gaining 14.13%. Other top pure-play performers included wind turbine component maker China High Speed Transmission Equipment Group, up 12.48%; Greek renewable energy developer Terna Energy , rising 11.22%; wind farm developer China WindPower Group, gaining 10.59%; and energy delivery technology developer American Superconductor ( AMSC), down 10.54%.