Arizona just turned on one of America’s biggest battery storage systems. The massive $106 million Tesla Megapack facility can store 1.3 gigawatt-hours of electricity – enough to power 76,000 homes for four hours during peak demand times.
Salt River Project and Plus Power LLC built this 340-megawatt system together. It’s now the largest standalone battery storage facility in Arizona. The project uses Tesla’s Megapack technology, which consists of modular lithium-ion batteries designed for utility-scale operations. Each unit can store up to 2,964.8 kilowatt-hours of energy. The latest Megapack 2 XL version offers 1 MW of power and 3.9 MWh of energy storage per unit.
The system works by charging up when there’s extra renewable energy on the grid, especially from solar panels during sunny days. Later, when people need more electricity in the evening, the batteries release that stored power. This process happens with 93.7% efficiency, meaning very little energy gets lost during charging and discharging.
This battery storage helps Arizona rely less on fossil fuel power plants. Traditionally, utilities fire up gas-powered “peaker plants” when electricity demand spikes. Now, the Megapack system can handle those peak times instead. This change reduces carbon emissions and helps fight climate change. Large-scale battery installations like this one are projected to increase significantly in 2023 and 2024 as more utilities adopt the technology.
The pre-assembled battery modules arrive ready to install, which speeds up construction compared to older systems. Tesla says this approach can cut engineering and construction costs by up to 40%. The batteries also include cooling systems to keep them running efficiently in Arizona’s hot climate.
Plus Power has experience with large Tesla battery projects, including one that replaced a coal plant in Hawaii. The company worked with Salt River Project to bring similar technology to Arizona. The modular design means the facility can expand in the future if needed.
The project supports Arizona’s growing solar industry by solving a key problem – what to do with extra solar power when the sun’s shining but people don’t need much electricity. By storing that energy for later use, the batteries make renewable power more reliable and beneficial.
This massive battery system represents a major step in modernizing America’s electric grid and moving away from fossil fuels.