NEW YORK (TheStreet) -- GT Solar (SOLR), JA Solar Holdings (JASO), Helix Energy Solutions (HLX) and Energy XXI (Bermuda) (EXXI) were top performers this week, while Vestas (VWRDY), Aventine Renewable Energy Holdings (AVRW) and LDK Solar (LDK) eroded substantial ground.Among the advancers, GT Solar topped the charts, jumping 18.2%. Ardour Capital reiterated a buy on the stock on improved prospects from the company's Sapphire business. JA Solar rose 10.5% and Helix Energy Solutions gained 8.3% the week of June 20. Energy XXI (Bermuda) advanced 8.3%. Analysts at Rodman & Renshaw maintained market perform on the stock and observed higher-than-expected production. Other winners were Rosetta Resources ( ROSE) up 7.1%, Brigham Exploration ( BEXP) rose 6.6%, Tesoro Corporation ( TSO) grew 6.6%, Holly Energy Partners ( HEP) added 6.6%, Cheniere Energy Partners ( CQP) gained 6.5%, Unit Corporation ( UNT) improved 6.5%, Atwood Oceanics ( ATW) and TC PipeLines ( TCLP) piled 6.3% each. Bill Barrett Corporation ( BBG) moved up 6.2%. Global Hunter Securities equity analyst Michael Bodino rated a new accumulate on the stock with a 12-month target price of $59 per share. Berry Petroleum ( BRY) gained 6% during the week. Oil States International ( OIS) rose 5.5% after its subsidiary secured a contract from Subsea 7 to supply 27 FlexJoint Steel Catenary Riser terminations and 40 receptacle assemblies for the Guara and Lula NE oilfields in Brazil. Other movers were Oceaneering International ( OII) rising 5.5%, Teekay LNG Partners ( TGP) up 5.2%, Weatherford International ( WFT) rose 5%, and Holly Corporation ( HOC) added 4.7% during the week. STR Holdings ( STRI) advanced 5%. Analysts at Maxim Group rated a new buy on the stock with a price target of $22 per share. PAA Natural Gas Storage ( PNG), Bristow Group ( BRS), Mcmoran Exploration ( MMR) and Dril-Quip ( DRQ) closed the week with gains of more than 4%. Vestas was the top lagger, shedding 13.3%. Citi rated a sell on the stock on stretched valuations. The brokerage says the company could miss its year-over-year order intake growth for 2011 of 7 to 8 GW. Aventine Renewable Energy Holdings declined 5.9% and LDK Solar lost 5.3% during the week. EnCana Corporation ( ECA) erased 4.6%. S&P revised Encana's outlook to negative on closure of PetroChina joint venture. Niska Gas Storage Partners ( NKA) pared 4.2%. UBS lowered its price target on the stock to $19 per share from $20 and maintained a neutral rating on it. Nabors Industries ( NBR) fell 4.2%. Analysts at Raymond James downgraded the stock to market perform from strong buy. Others on the downside were Occidental Petroleum ( OXY) sliding 3.3%, Legacy Reserves ( LGCY) dropping 3.3%, Nexen ( NXY) erasing 3.1%, Frontline ( FRO) losing 2.5% and Imperial Oil ( IMO) eroding 2.1%.