Evergreen Solar Inc. (ESLR) and ReneSola Ltd. (SOLA) sank in New York after reporting sales of photovoltaic solar panels have been slower than analysts expected.

Evergreen dropped 54 cents, or 26 percent, to $1.54 as of 10:221 a.m. in Nasdaq Stock Market trading. Earlier it was down as much as 34 percent, the largest intra-day decline since October 2002. ReneSola’s American depositary receipts fell as much as 78 cents, or 8.8 percent, to $8.07 a share. A close at that price would be the lowest since Dec. 17.

Evergreen Chief Executive Officer Michael El-Hillow said slower-than-expected sales may force the company to raise cash. Marlboro, Massachusetts-based Evergreen held about $33 million in cash and cash equivalents as of April 26, down from $38.5 million on April 2.

“Uncertainties regarding feed-in-tariffs and other subsidy programs have substantially slowed the demand for solar panels in 2011,” El-Hollow said in a statement yesterday.

Wunderlich Securities Inc. analyst Theodore O’Neill downgraded the company today to “sell” from “hold.”

ReneSola said product sales slumped 15 percent in the first quarter to $328.2 million, from $386.4 million in the fourth quarter. For the second quarter, sales will be in the range of $280 million to $300 million, less than the $337.1 million that analysts had expected.

“We hold a cautious outlook for demand in Europe, particularly due to the uncertainty and policy changes in Italy,” the Jiashan, China-based company’s Chief Executive Officer Xianshou Li said today in a statement.