SAN JOSE, CA  Sprig Electric is now among the first electrical contractors in the nation to pair Tesla's Powerpack battery with a 350-kW commercial rooftop photovoltaic (PV) system to optimize energy savings. The pairing, installed by Sprig Electric at their corporate headquarters in San Jose, California, will cut the building's total energy costs by 80 percent to 95 percent.

The components of the system include 1,177 solar panels that are spread over 20,000 square feet of the building's rooftop. The 500kWh/250-kW Tesla Powerpack battery system is installed in the Sprig Electric parking lot and is connected to the grid and the PV system. In addition to five, 100-kW Powerpack commercial batteries, the system includes a 250-kW inverter and a DC combiner. The footprint is approximately 10 feet by 16 feet.

The Powerpack system maximizes consumption of on-site solar power, avoids peak electrical charges, and facilitates the purchase of energy when it is the cheapest. It acts as an energy storage system for grid power and the photovoltaic system, significantly increasing the utility cost savings that Sprig Electric will realize from using solar electricity alone, thus cutting utility bills by as much as 80 percent to 95 percent.

Customers can use the battery's stored electricity to reduce peak demand. The batteries are regulated to charge during a low demand period when a surplus of energy is available. They then discharge their stored power when demand is high and the rates are high. This makes for additional savings and lowers the utility bill.

The installation at Sprig Electric headquarters is regulated by a sophisticated control system, which looks at building loads, the amount of energy the panels are producing, and the amount of power that's stored in the battery. It then shifts power around appropriately based on those conditions.

The recently commissioned combo PV/battery storage system installed at Sprig Electric generated 6.7-MWh of energy and saved 4.94 tons of carbon dioxide in the first eight wintery days.

"We are extremely happy at how this combo solar system has performed in its first week," said Michael Clifton, Engineering/Operations Manager for Sprig Electric's Energy Efficiency Division. "We are excited to begin tracking this unique systems' metrics and ultimately provide alternative energy solutions for our clients and partners alike. We believe the market for battery storage is really going to take off in the coming years." Clifton said that both rebates and tax credits are available for the battery system purchase.

The Powerpack is based on lithium ion battery technology. The batteries' modular design is adapted from the technology used in those for Tesla's electric cars. The Powerpack is a scalable system, which can be expanded by connecting additional Powerpacks, and inverters up to hundreds of MegaWatts.

Clifton said Sprig Electric chose to procure the Tesla Powerpack system because of Tesla Energy's clear lead in battery technology. "Tesla is solid in their battery technology," said Clifton. "They use a very sophisticated cooling system that keeps the batteries operating at even temperatures. Their batteries are quite compact, considering the energy within them. We did look at other manufacturers, but those are mostly in the developmental stage."