Evergreen Solar Advances String Ribbon Technology; Growing Two Ribbons from One Furnace Doubles Output and Lowers Costs

Evergreen Solar, Inc. (Nasdaq: ESLR), a developer, marketer, and manufacturer of photovoltaic (solar power) products for the worldwide market, announced today that it has developed the latest advancement in its proprietary String Ribbon(TM) technology for manufacturing solar cells that involves simultaneously growing two silicon ribbons, rather than one, from each crystal growth furnace. The Company expects this development to more than double the output of its crystal growth furnaces.

MARLBORO, Mass.--(BUSINESS WIRE)--Dec. 4, 2002--Evergreen Solar, Inc. (Nasdaq: ESLR), a developer, marketer, and manufacturer of photovoltaic (solar power) products for the worldwide market, announced today that it has developed the latest advancement in its proprietary String Ribbon(TM) technology for manufacturing solar cells that involves simultaneously growing two silicon ribbons, rather than one, from each crystal growth furnace. The Company expects this development to more than double the output of its crystal growth furnaces.


The Company expects to introduce double ribbon into production in late 2003 with new furnaces as well as retrofitting existing furnaces. Evergreen Solar has filed a patent for the process.

"This important milestone reinforces Evergreen's position as a leading technical innovator in the solar industry," remarked Mark A. Farber, President and Chief Executive Officer of Evergreen Solar. "We have taken our unique core technology, originally developed at MIT, and expanded and improved it. Doubling the throughput of each furnace leverages capital cost, floorspace, energy consumption, labor, and consumables, which are expected to have an important impact on reducing costs. Coupled with our other innovative production techniques, we are making measurable progress towards our goal of establishing Evergreen as a leading force in the world market for solar power. In the past six quarters, sales have increased ten-fold and unit costs have been substantially lowered. We believe that more exciting developments lie ahead."

Dr. Jack I. Hanoka, Vice President and Chief Technology Officer of Evergreen Solar, stated, "With the invaluable contributions of our research scientist, Richard Wallace, we have made significant progress on this particular project over the past nine months. We are exploring further advancements of our String Ribbon technology, including the potential to grow more than two ribbons from one furnace, as well as thinner ribbon."

"This development continues our track record of improving String Ribbon technology at our Marlboro factory," continued Dr. Hanoka. "In early 2001, we doubled furnace productivity by increasing ribbon width from 2.2 to 3.2 inches and boosting the growth speed by 40%. We're aiming to do this again with double ribbon - all without increasing the furnace size."

String Ribbon combines the most attractive attributes of conventional crystalline silicon and emerging thin films. It achieves the reliability, stability, high efficiency, and market acceptance of crystalline silicon - without the inherent cost and waste of sawing solid silicon blocks. This technique embodies the efficient material utilization and potential for continuous processing of thin films, but with a more manufacturable process. String Ribbon is one of the most material and energy-efficient and environmentally friendly crystalline silicon processes in the industry.

In the String Ribbon technique, two high temperature strings are pulled vertically through a shallow silicon melt, and the molten silicon spans and freezes between the strings to form a ribbon of silicon. With the new development, four strings will form two ribbons. The process is continuous: long strings are unwound from spools; the melt is replenished; and the silicon ribbon is cut into strips for further processing, without interrupting growth. This advantage in material efficiency means String Ribbon can yield over twice as many solar cells per pound of silicon as conventional methods.

About Evergreen Solar, Inc.

Evergreen Solar, Inc. (www.evergreensolar.com) develops, manufactures, and markets solar power products utilizing the Company's patented solar power technologies. The products provide reliable and environmentally clean electric power in global markets. Solar power applications include wireless power for remote homes, water pumping, lighting, and rural electrification, as well as complete power systems for electric utility customers choosing to generate their own environmentally benign power. Evergreen Solar is one of the only fully integrated, independent PV manufacturers in the U.S - producing solar wafers, cells and panels.

String Ribbon is a trademark and Evergreen Solar(R) is a registered trademark of Evergreen Solar, Inc.

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