The surge in alternative energy interest has shed some light on two solar stocks, both of which are assets in solar exchange traded funds (ETFs).

LDK Solar (LDK) gave quarterly results that were so hot, they burned analysts’ low expectations. A sequential leap of 50% in wafer capacity by the quarters’ end gave way to an 89% rise in sales for the period. LDK also raised its annual revenue estimates by a big 50%, reports Kirk Shinkle for U.S. News & World Report.

The company also signed a five-year, 300 megawatt supply contract with India’s XL Telecom & Energy, beginning in the first quarter of 2009, reports Matt Daily for Reuters.

Canadian Solar (CSIQ) has been gaining interest with modules that use low-cost alternative material from Timminco, with big-name suppliers backing their game. LDK is rumored to be a possible buyer of the latest silicon. Canadian Solar, Q-Cells and CaliSolar are already purchasers of the silicon, report Jennifer Kho and Ucilia Wang for Greentech Media.

With oil prices being what they are, the solar energy industry is seeing growth in the range of 30%-50% a year, says Beacon Equity.