Ahead of an expected announcement of a new rooftop shingle solar power system today, Tesla unveiled the second iteration of its commercial lithium-ion battery storage system -- the Powerpack 2.
The Powerpack 2 doubles the power capacity over the original Powerpack from 100 kilowatt hours (kWh) to 200kWh.
Powerpack 2 is also now matched with a new inverter, designed by Tesla and manufactured at the Gigafactory.
The original Powerpack contained 16 individual battery pods, each with an isolated DC-AC converter. The "pod" architecture and onboard power electronics allowed for individual units to be easily swapped out, Tesla said.
Tesla is betting on solar and battery storage systems, having partnered with Panasonic to manufacture batteries in its Gigafactory outside Reno, Nev., and having announced its intent to acquire SolarCity, the nation's largest residential rooftop solar installer.
Research from Bloomberg New Energy Finance (BNEF) forecasts massive growth in the energy storage market, first in utilities, then in corporations seeking to reduce their overhead costs.
The "Global Energy Storage Forecast, 2016-2024" shows that the annual investment in energy storage systems will increase six-fold to $8.2 billion in 2024.
The Powerpack 2 is a redesigned and reengineered system that integrates a bi-directional inverter without a transformer that, while doubling the electricity capacity, keeps the same system footprint as the original.
Tesla's new inverter, which is the electronic device that changes direct current (DC) electricity coming from solar photovoltaic panels to usable alternating current (AC), is modular; uses updated power electronics that offer better performance; delivers 99% peak efficiency; and responds faster to commands.
The improvements in the Tesla inverter contribute to a higher power density per square foot. The inverter can operate in grid-tied or off-grid (behind the meter) applications, and can switch between both conditions.
"It is the lowest cost, highest efficiency and highest power density utility-scale inverter on the market," Tesla stated in a blog today. "It also significantly simplifies the installation process of the entire Powerpack system by integrating a number of previously independent components into the inverter itself."
The original Powerpack system retailed for $25,000 each. Tesla CEO Elon Musk has said the Powerpack can scale infinitely, even powering small cities.
The full price of the Powerpack 2 will be available on Tesla's website and will combine the battery, inverters and cabling/site support hardware.
Unlike Tesla's Powerwall battery system, which has 5kW of steady output and 7kW of peak output and marketed for home use, the Powerpack is aimed at being an energy backup for businesses that can also alleviate peak loads drawn from standard utility systems. That can help businesses avoid or reduce peak demand charges.
At one time, U.S. electric utilities charged flat rates for electricity. But that has changed over the past 30 years and utilities in 16 states, such as Hawaii, New York and California, charge additional fees for electricity use that exceeds pre-set limits during peak hours.
Large corporations will often have "demand meters" installed by utilities that register the highest rate of electrical flow during a billing period. A demand meter records an average flow for every 15-minute interval. The enterprise is billed for the highest average 15-minute flow typically over a monthly billing cycle. So, if an enterprise goes over its typical energy use, that becomes the rate at which it's charged.
Tesla's Powerpacks are already being deployed in several large-scale projects, including Southern California Edison's Mira Loma substation and the Kauai Island Utility Cooperative. The Powerpack systems for the latter two are being built now at Tesla's Gigafactory and, when deployed later this year, will be the two largest lithium ion battery storage installations in the world, the company claims.
A California real estate development company has also announced plans to install Tesla batteries in up to two dozen of its highest profile offices in the Los Angeles area.
The Powerpack 2, as with the original Powerpack, comes in an enclosure that is outdoor rated for all environments.
"No additional structures or covers are required, simplifying installation and lowering site preparation expenses," Tesla stated.
The Powerpack 2 has an internal liquid cooling and heating system that allows for precise temperature control. A dual coolant and refrigerant loop system, adapted from Tesla's Model S sedan, helps smooth battery performance in all climates with better efficiency than air cooling, the company said.
The new Powerpack 2s will use a "high volume, high reliability architecture that Tesla claims has been tested over the one billion miles driven in their Model S all-electric sedans.
"Combined with hundreds of embedded sensors, Powerpack offers unparalleled performance, safety and reliability," Tesla stated.