TECOGEN Distributed Generation Equipment Earns Certification Under California Rule 21 Tecogen Is One of Only Four Manufacturers Certified to Meet State's Connectivity Standards WALTHAM, Mass., April 2, 2003 - Tecogen Inc. announced today that its 60 kW and 75 kW natural-gas powered cogeneration systems have been certified to meet all of California's requirements for interconnectivity between distributed generation systems and the state's electric utilities. After rigorous testing by two nationally recognized testing laboratories, Tecogen's systems have been added to California's list of "Type Tested and Production Tested" distributed generation equipment. This makes Tecogen one of only four suppliers with equipment certified to meet the state's standards governing interconnections between non-utility-owned distributed generation and a utility's distribution grid. Distributed generation refers to small-scale power-generating technologies such as Tecogen's that are located at the end-user's site and interconnect with a utility's power distribution grid. In order to set up an on-site system, certain interconnection and operational requirements must be satisfied before the customer is allowed to connect to the grid. In 2000, California became one of the first states in the country to establish interconnectivity standards for distributed generation (DG) technologies through the adoption of Rule 21 by the California Public Utilities Commission. Under Rule 21, specific DG systems (including Tecogen's) can be pre-certified, which will qualify them for a "simplified interconnect" review process by the electric utilities, instead of the longer, more costly review that is required for non-certified units. In addition, requirements for secondary relay devices have been waived for Tecogen installations. These devices help protect the utility grid from interruptions and disturbances that can be caused by non-certified equipment. "This certification is very significant for us," said Bob Panora, president of Tecogen. "In the past, the review process for interconnections has been very cumbersome - often taking months and months. We are also very pleased that we've earned the exemption from secondary relay devices, which add significant time and expense to an installation. This certification definitely gives us a strong advantage in siting our cogeneration units, especially in settings such as large universities and medical campuses." California has proven to be an attractive market for Tecogen's distributed generation technology; the company now has approximately 300 systems installed and operating throughout the state. For more information about California's interconnectivity standards, please go to http://www.energy.ca.gov/distgen/interconnection/certification.html. About Tecogen In the U.S., Tecogen is the leading manufacturer of reliable and efficient low-emission packaged cogeneration units. Based on low-cost, mass-produced internal combustion engines, Tecogen's modular units use natural gas to produce electricity right at the customer's facility, capturing the waste heat to produce domestic hot water. Tecogen has a nationwide installed base of more than 1,300 units, which it supports through an established network of engineering, sales, and service support. Tecogen is based in Waltham, Massachusetts, with annual revenues of approximately $13 million. For more information, go to www.tecogen.com.