10+ KW Grid Tie Solar
Completed in October 2013.
Inverters: SMA Sunny Boy 5000TL
Mounting hardware: S-5! CorruBracket
The inverter was chosen for the energency power feature. With nearly all other systems at the time of installation, when the grid fails, the system is useless. The Sunny Boy 5000TL has a feature that allows the system to generate up to 1500 watts of AC power during grid failure if there is adequate sun exposure. At the time of installation, the largest size inverter with this feature was 5000 watts. That is why the system is divided into two sections. Production history for the first two years of services averaged very close to 1000 KW-Hr per month. Installed cost was $3.00 per watt. Two years later, installed costs of $2.50 per watt or less are possible.
The roof of the 70 year old building was wavy. The mounting stud usually used was replaced with 8 mm stainless steel threaded rod about 8-1/2" long. This provided for accommodation of the waviness and allowed the plane of the panels to be flat.
As of this posting, November 2015, consideration is being made for the addition of a battery back-up system for grid failure. The battery system will be some distance from the PV array and inverters, so an AC coupled system is being planned. One of the issues of AC coupled systems is that during grid failure the PV inverters must be controlled to deliver only the AC power that the loads, including battery charging, can accommodate. Because they are from the same manufacturer, the SMA Sunny Island inverter/chargers are compatible and can communicate this information to the SMA PV inverters. Stay tuned.