Harvard Business School has just completed a large rooftop solar installation using AC modules from ET Solar powered by SolarBridge microinverters. Massachusetts-based solar energy company Solect Energy Development, LLC installed the 80kW project at Tata Hall, a new executive education facility.

The Harvard Business School project - the first of its kind on a university - represents a growing trend to install ACPV on larger commercial and institutional systems. The project is composed of 320 integrated AC modules, unique for their ability to generate AC power direct from each panel. ET Solar provided the modules, which include SolarBridge Pantheon II microinverters factory-installed on each panel to convert solar-generated DC power to AC power.

Wind and shade were a particular challenge at Tata Hall, which comprises three high-rise, flat-roof buildings that are taller than any surrounding buildings. The Harvard facilities team selected ACPV because of its ability to maximize the output of each solar panel.

Shadows from roof structures and equipment would present issues for DC-based systems using string inverters, because shade on any individual module would compromise the power output of the entire string of modules. In addition, ACPV was selected to increase system up-time and reduce operations and maintenance expenses by eliminating any single point of failure in the system.

Using a web-based monitoring system, facilities staff can keep tabs on ACPV system production anywhere, anytime, down to each individual module. "Green screen" monitors will keep Tata Hall occupants apprised of how much energy the solar array is producing at any given moment to offset enough of the building's power consumption to allow Harvard to advance from Gold to Platinum LEED certification.

"Solar is an excellent investment for universities, which are under increasing pressure to reduce costs as well as energy consumption," said Bill Mulligan, president and CEO of SolarBridge Technologies.

"When an institution with the prestige and longevity of Harvard Business School chooses ACPV for its solar projects, significant long-term financial and environmental benefits have been demonstrated."

The Tata Hall project addresses Harvard University's commitment to reduce greenhouse gases 30 percent by 2016 using 2006 as a baseline and including all future growth. Sustainability and renewable energy projects at Harvard Business School have contributed to a 62 percent recycling rate, 23 percent reduction in energy use and 43 percent reduction in greenhouse gas emissions.

The completion of the Tata Hall PV array is the second at the Harvard Business School.

"We are very proud to be associated with the Harvard project," says Dennis She, president and CEO of ET Solar.

"ET Solar is committed to providing excellent quality products that are highly reliable, efficient and productive. ET's AC solution provides all of these benefits and gets high marks for the simplicity of installation - which is increasingly important for larger installations."

"Solect is very excited to help Harvard's Business School achieve platinum LEED certification on the Tata project," says Scott Howe, Partner at Solect Energy.

"The project's complexity included a multi-tiered roof with many mechanical units and attachments resulting in shading on various parts of the arrays throughout the day. The AC solar panel solution was an ideal fit to deliver maximum system production and efficiency. "