Each of Clean Edge and Nasdaq's three benchmark clean-tech stock indexes ended last week higher, with the Nasdaq Clean Edge Green Energy Index (CELS) gaining 1.77%, the Nasdaq OMX Clean Edge Global Wind Energy Index (QWND) rising 1.62%, and the Nasdaq OMX Clean Edge Smart Grid Infrastructure Index (QGRD) up 2.28%.The overall market also gained -- the S&P 500 was up 3.13%; the Nasdaq rose 2.76% and the Amex Oil Index ended the week 2.95% higher. CELS -- up 1.77% for the week and 49.44% 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, four of the five component companies were in positive territory. Energy intelligence had 13 components up and one down. Seven energy storage and conversion components were in positive territory while three lost ground. For renewable electricity and fuels, six components were up, eight were down, and one remained unchanged from the previous week's close. CELS' best performer for the week was lithium-ion battery maker Valence Technology ( VLNC), gaining 15.38%. Rounding out the top five CELS performers were geothermal power developer Raser Technologies ( RZ), up 10.75%; semiconductor maker IXYS ( IXYS), rising 10.75%; lithium-ion battery manufacturer Ener1 ( HEV), gaining 10.19%; and smart meter manufacturer Itron ( ITRI), up 9.05%. CELS' worst performer last week was demand energy management firm EnerNOC ( ENOC), which declined 15.04%. Other worst performers included energy storage product maker Maxwell Technologies ( MXWL), down 10.28%; solar cell and module manufacturer Canadian Solar ( CSIQ) lost 9.35%; demand management service provider Comverge ( COMV) was down 7.31%; and power management semiconductor developer Advanced Analogic Technologies ( AATI) dropped 6.50%.