Sprig Electric is one of the first electrical contractors (ECs) in the country to pair Tesla’s Powerpack battery with a 350-kilowatt (kW) commercial rooftop photovoltaic (PV) system. In its first month, the paired system has cut energy costs at its San Jose, Calif., headquarters by 80–95 percent.


“The solar system has been producing about a third of our overall load in a day,” said Michael Clifton, operations manager of Sprig Electric’s Energy Efficiency Division. “In two to five years, [energy storage] will be a huge market for ECs.”


This system includes 1,177 solar panels on 20,000 square feet of the building’s roof. Sprig installed a 500-kilowatt-hour/250-kW Tesla Powerpack battery in the parking lot and connected it to the grid and PV system. It also includes five 100-kW Powerpack commercial batteries, a 250-kW inverter and a direct-current combiner. It can expand with additional Powerpacks and inverters up to hundreds of megawatts. The battery and solar-power systems are separate and parallel.


By acting as energy storage for grid and PV power, the Tesla system optimizes energy savings, increasing utility savings from solely using solar electricity. Other parts of the country use similar battery systems to take the load off existing generators by allowing the system to correct frequency regulation, Clifton said.


A control system provides regulation. It factors in the amount of energy from the panels, amount of power stored in the battery and building load and moves power around based on these factors.


The batteries charge in low demand periods when an energy surplus is available and then discharge stored power during times of high demand and higher rates.


Load shifting and peak shaving are two advantages of the system.


Sprig Electric went with Tesla because of the smaller system footprint, compact batteries and cooling technology, and easy-to-use control system, Clifton said. 


Tesla Powerpack batteries are based on lithium-ion technology, and their modular design was adapted from Tesla electric vehicles.


Sprig Electric expects this system to dramatically reduce energy costs. Rebates and tax credits are also available.


Companies with high peak demands, such as manufacturing facilities or utilities, will appreciate the system’s ability to smooth out loads. It also offers load shifting for companies with certain rate structures or large ratios between peak and off-peak.