Rosendin Electric, a San Jose, Calif.-based private electrical contractor, and Ampt LLC, a power conversion technology company, have announced a new offering to repower large-scale solar photovoltaic systems that are underperforming or that require inverter replacement.

With over 2.4 GW of project experience installing mid- to large-scale solar PV systems and a nationwide network of certified and local electricians, Rosendin Electric says it is now extending its services to include upgrades to existing PV systems using Ampt string optimizers.

According to Ampt, the solution uses its string optimizers to improve power plant performance and increase return on investment.

“PV power plants naturally degrade over time, and there are a great number of them underperforming,” says Chris Chappell, director of engineering and preconstruction at Rosendin Electric. “Using Ampt string optimizers, we can repower systems to improve production and maximize ROI over the remaining system life.”

Ampt explains that its string optimizers are DC-to-DC converters that put dual maximum power point trackers on each string of PV modules to improve the system’s lifetime performance, asserting that its patented technology recovers approximately 60% of energy losses caused by the electrical imbalances that occur as systems degrade. When used to repower existing PV systems, Ampt optimizers are connected to the existing wires and combiners and include optional wireless communication for remote monitoring and enhanced operations and maintenance (O&M).

Rosendin Electric says its repowering service includes a performance assessment, engineering, installation of Ampt string optimizers, and re-commissioning of the system. Full-service O&M support is also available to customers.

Further, Rosendin Electric also uses Ampt string optimizers to provide customers with enhanced inverter replacement services. As PV power plants age, many inverters experience significant faults and downtime or fail after reaching their expected operating life, the company explains. Often, the original model inverter is either expensive and inefficient compared with modern inverters or is no longer available, causing substantial reworking of the system or portions of the PV plant to remain offline. Rosendin Electric says its inverter replacement service avoids these costly outcomes by deploying Ampt optimizers with modern inverters.

“Combining Ampt string optimizers with the latest inverters is a cost-effective alternative when replacing inverters,” says Chappell. “In addition, the optimizers enhance system energy production over the remaining life of the power plant.”

Ampt optimizers allow 1,000 V inverters to deliver full-rated output power in 600 V systems. Likewise, 1,500 V inverters achieve full-rated output power in 1,000 V systems with Ampt. The result is a lower-cost-per-watt inverter utilizing modern technology and a higher-performing PV array.

In addition, Ampt optimizers are also used to expand systems by adding more PV modules to the existing inverters while operating within specification. Ampt enables these “high DC ratio” systems to operate at DC/AC ratios of 2-to-1 or more to generate up to 70% more energy. Rosendin Electric provides the know-how and engineering, procurement and construction services to customers to deploy high DC ratio systems using Ampt in order to maximize returns.