Reuters: Solar stocks rally after Goldman Sachs says the long-term outlook is sunny for the solar sector thanks to electricity demand and green policies. Goldman upgrades Conergy (CGYG.DE: Quote, Profile, Research) to “buy” from “neutral” and Q-Cells (QCEG.DE: Quote, Profile, Research) and Solon (SOOG.DE: Quote, Profile, Research) to “neutral” from “sell”. They rise between 5 and 7 percent and are some of the top gainers on the DAX Technology stocks …