The first PV system at Harvard Business School, a 36.5 kW PV array, has been installed on HBS's Shad Hall campus in Boston, Massachusetts. The array comprises 192 panels, and was designed and installed by Global Resource Options (GRO) of White River Junction, Vermont.
Although the solar array was not a specialized R&D project for the university, HBS stood behind the installation and helped secure financing for the project. While the School was quick to support the installation, the motivation originated with the students. 'The photovoltaic system simply made economic sense for HBS,' explains Brian Robertson, a student at HBS and president of the campus Sustainability Society, who spearheaded the drive to obtain the grant funds and implement the system. 'Based on the installed costs, the grants that were obtained, and the power generation estimates, HBS will obtain less expensive power from the photovoltaic system while stabilizing their power costs and cleaning up the environment. It's a true win-win-win situation.'
Working with PowerLight Corporation as a certified dealer, GRO designed a PowerLight PowerGuard flat-roof system using Sanyo HIT-190 PV modules, which are only available through PowerLight. The Sanyo modules were chosen for their high power density, which allowed HBS to install the system on one roof, rather than two as originally planned. This leaves additional space for future expansion, and saved money through fewer required roof preparations.
GRO was subject to a competitive bidding process for the project, but the company achieved efficiency gains by splitting the panels into different strings, which allowed the system to cope well with a slight shading on its area. Shading issues would have degraded overall array performance by 25% with a single large inverter. However, by using multiple string inverters, the array never loses more than 12.5% to shading.
The installation uses 16 of SMA America's SB 2500u Sunny Boy inverters, with SMA data monitoring equipment, since the School expressed a desire to make the system data available for interfacing with the campus' computer network.