May 9, 2005

Sustainable Energy receives UL listing for Sunergy 5 solar inverter

Sustainable Energy Technologies' (SET) Sunergy 5 solar inverter has been certified by Underwriters Laboratories (UL) as compliant with UL 1741 standards for grid-tied applications. UL 1741 is a requirement that power conversion products must meet in order to be sold commercially in North America.

"UL listing is an important milestone for Sustainable Energy," said company president and CEO Michael Carten. "Not only does it clear the way for commercial sales in the North American market, it is also a key confidence factor for potential partners in Europe. With this behind us, we are able to begin effectively marketing our products, and we are targeting a number of potential partnerships that will enable us to penetrate high growth markets in Europe."

The Sunergy inverter uses the same proven technology developed for stationary fuel cell applications to maximize total power output of the solar modules through a wide range of operating conditions. Benefits cited by SET include:

high efficiencies (a weighted average of 93%, making Sunergy 5's electrical conversion efficiencies among the highest in the industry, says SET);

no thermal rollback: while most grid-interactive inverters reduce power output in hot weather-a situation known as "thermal rollback"-the Sunergy operates at full power to 50*C (122*F), maintaining maximum continuous power in the hottest and sunniest parts of the day; and

reliability: the Sunergy inverter platform has been designed to meet the stringent reliability standards set for stationary fuel cells and has been tested extensively in that very difficult environment. As a result, the company provides a ten-year product warranty for its inverter, compared to the more typical two- to five-year warranties.

In other activities, SET reports that it has delivered the first of its next generation inverter platforms for stationary fuel cell applications. The new inverter platform has a peak "stack-to-grid" electrical conversion efficiency of over 94%; this is the highest in the industry, says the company.

"Unlike most inverter designs, Sustainable Energy's fuel cell inverter efficiencies actually increase as the fuel cell stack voltage drops," Brent Harris, SET's director of technology development, explained. "The ability to achieve high efficiencies at lower voltages is a critical design condition for the industry, as the fuel cell stack voltage decreases with increasing power output. For these reasons, we believe our efficiency profile is an ideal match for the output characteristics of most fuel cell stacks."

Power inverters are an essential part of the infrastructure for the stationary fuel cell industry, converting the direct current output of fuel cell stacks into high-quality alternating current needed by electrical devices. Sustainable Energy's patented design offers a new approach to power conversion, enabling a single step conversion from low voltage dc power to grid standard ac voltage with minimal loss of energy, and active bi-directional control over the fuel cell current.

"What is also especially exciting for us," said Harris, "is that we are now using the same power electronics, controls software, and transformer design for both solar PV [photovoltaic] and fuel cell applications. This is a very significant milestone in our quest to deliver, what we believe will be, the industry's first "universal" inverter-an inverter which uses the same power electronics for all distributed generation and storage technologies."

SET develops, manufactures and markets advanced power electronics products for emerging alternative and renewable energy markets. More information is available from Phil Winters at Sustainable Energy Technologies, 416/830-6668, E-mail, Web site, or on the UL Web site,

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