20 August 2012
The recently completed grid-tied PV system is not only providing green power in the Green Mountain State, but is serving as a test site for smart modules being developed by Upsolar and Tigo Energy. At 2.2MW, it’s the largest in the state of Vermont (US).
With 9562 polycrystalline modules in the installation, micro-inverters would have been prohibitively expensive. But the new optimizers are using Tigo’s Module Maximizer technology. It looks like a PV module, according to Stuart Schonfield of Executive Advisor at Upsolar, but with smart components on the back, the customer is getting web-based monitoring on a module level and an increase in efficiency in energy production of 3 to 5% over systems without the optimizer. Other benefits include reduced cost and the ability to adjust for irregularities in any part of the system.
The test is set up with 2MW using the Tigo optimizers with 200kW that are not. “Everything is identical, so we’ll have a very good understanding of the performance.” Kale Inoue, one of the system owners said that the Tigo and non-Tigo modules are dispersed throughout the system so they’ll get meaningful results.
Upsolar mounted the Tigo units in their factory because an integrated unit was not yet available. In the future the Tigo Maximizers will come preinstalled on the modules. Troy Dalby of Upsolar noted, “Installers will get the modules and plug them together like we normally do.”
In addition to the monitoring ability of the smart modules, they also have the ability to integrate arc fault detection. The digital monitoring system also provides data on how each individual module is performing at any given moment.
The system is backed by Upsolar’s Reinforced warranty with trigger points at years 3, 7, 12, 20 and 25. Basically the way this works is, for example, in years 1 to 3, if the power output is less than 97% of the minimum “Peak Power at Standard Test Conditions,” Upsolar will repair or replace the module or refund the customer the percentage of the corresponding loss, prorated. At each trigger point, the minimum peak power expectations drop off slightly, but with 80% being the lowest at the 25-year period.
The system owners, Naoto and Kale Inoue, have been in the PV business for 35 years as owners of Talmage Solar Engineering, Inc., based in Arundel, Maine. This self-financed project won a spot through a lottery, enabling it to take part in the state’s feed-in tariff (FiT) program. 2.2MW was the limit to the size of the system. Kale said that it was purely by luck that they were awarded the FiT project. With 300 applicants, only 12 were chosen. Talmage Solar chose the site in Sharon, Vermont because of its south face and proximity to power lines.
Area residents have been nothing but supportive of the project, but the main challenge was the permitting process in Vermont, which Kale deemed “cumbersome.” Having gotten through the paperwork, the installers worked through the record-breaking heat of this summer in Vermont to ready the system for its ribbon-cutting ceremony on 11 August.
Written by Anne Fischer, Managing Editor, Solar Novus Today