Tesla Powerwall - New Battery Technology

The Powerwall and Powerpack are rechargeable lithium-ion battery stationary energy storage products manufactured by Tesla Motors. The Powerwall is intended for home use and stores electricity for solar self-consumption, time of use load shifting, backup power, and off-the-grid use. The larger Powerpack is intended for commercial or electric utility grid use and can be used for peak shaving, load shifting, backup power, demand response, microgrids, renewable power integration, frequency regulation, and voltage control.

Announced in 2015, with a pilot demonstration of 500 units built and installed during 2015, production of the product was initially at the Tesla Fremont factory before being moved to the under construction Gigafactory 1 in Nevada. The second generation of both products were announced in October 2016.

History

Tesla started development in 2012, installing prototypes at selected industrial customers. In some cases, PowerPacks have saved 20% of the electrical bill.

The Powerwall was originally announced at the April 30, 2015 product launch with power output of 2 kW steady and 3.3 kW peak, but Musk said at the June 2015 Tesla shareholders meeting that this would be more than doubled to 5 kW steady with 7 kW peak, with no increase in price. He also announced that Powerwall deliveries would be prioritized to partners who minimize the cost to the end user, with a Powerwall installation price of US$500.

When originally announced in 2015, there were to be two models of Powerwall delivered: 10 kWh capacity for backup applications and 7 kWh capacity for daily cycle applications. But by March 2016, Tesla had "quietly removed all references to its 10-kilowatt-hour residential battery from the Powerwall website, as well as the company's press kit. The company's smaller battery designed for daily cycling is all that remains."

The 10 kWh battery as originally announced has a nickel-cobalt-aluminum cathode, like the Tesla Model S, which was projected to be used as a backup/uninterruptible power supply, and had a projected cycle life of 1000â€"1500 cycles.

In October 2016, Tesla announced that nearly 300 MWh of Tesla batteries had been deployed in 18 countries.

The Powerwall 2 was unveiled in October 2016 at Universal Studios' Colonial Street, Los Angeles, backlot street set and is designed to work with the solar panel roof tiles to be produced by SolarCity.

Powerwall Specifications

Since March 2016, there was only a single model: the 6.4 kWh version for daily cycle applications, before the Powerwall 2 was introduced:

^a Includes inverter. ^b Installation cost not included

Powerpack Specifications

Versions

The first generation Powerwall has a 6.4 kWh capacity for daily cycle applications. For families with larger energy needs, multiple powerwalls can be connected to expand the capacity even higher. A previously announced 10 kWh capacity model designed for backup power purposes was quietly discontinued in March 2016, as the 6.4 kWh version can also be configured to act as backup power.

The Powerpack is a bigger unit with 100 kWh (first generation) and 210 kWh (2nd generation) of storage for commercial and utility grid use. In order to meet the variety of energy needs in industry, "Powerpack is infinitely scalable", said Elon Musk. Tesla's objective is to "fundamentally change the way the world uses energy" by "fostering a clean energy ecosystem and helping wean the world off fossil fuels" using backup energy storage for renewable energy. The Powerpack 2 has 200 kWh of storage, probably using the 2170 cell by the end of 2016.

Technology

The Powerwall is optimized for daily cycling, such as for load shifting. Tesla uses proprietary technology for packaging and cooling the cells in packs with liquid coolant. Elon Musk, the chairman, CEO and product architect of the Tesla company, promised not to start patent infringement lawsuits against anyone who, in good faith, used Tesla's technology for Powerwalls as he had promised with Tesla cars.

The daily cycle 7 kWh PW1 battery uses nickel-manganese-cobalt chemistry and can be cycled 5,000 times before warranty expiration. The Tesla Powerwall has a 92.5% round trip efficiency when charged or discharged by a 400â€"450 V system at 2 kW with a temperature of 25 degrees, and when the product is brand new. Age of the product, temperatures above or below 25 degrees Celsius, and charge rates or discharge rates above 2 kW would lower this efficiency number, decreasing the system performance.

First generation Powerwalls includes a DC-to-DC converter to sit between a home's existing solar panels, and the home's existing DC to AC inverter. If the existing inverter is not storage-ready, one must be purchased. The second generation Powerwall incorporates a DC-to-AC inverter of Tesla's own design. Production of the 2170 cell for the PW2 and PP2 began at Gigafactory in January 2017.

The National Fire Protection Association conducted two worst-case scenario tests in 2016, igniting Powerpacks to initiate thermal run-off. The design contained damage to the structures.

Market

Powerwall

The Powerwall was unveiled on April 30, 2015, with a 7 kWh Powerwall model that would retail for US$3,000 and a 10 kWh model at US$3,500. Shipments of 500 pilot units were planned to begin in the late summer of 2015. Musk indicated that he believed the low Tesla price would cause other storage producers to follow. Before the April 30, 2015 unveiling, some existing solar customers participated in a demonstration program and paid up to US$13,000 for a 10 or 15 kWh Tesla battery.

As of May 2015, Powerwalls were sold to companies including SolarCity for installation. SolarCity was running a pilot project in 500 California houses, using 10 kWh battery packs. A market overview calculates Powerwall 2 at 0.23 Australian dollars per warranted kWh.

Volume tendency

As of May 2015, Tesla Powerwall had already sold out through to the middle of 2016. Reservations within the first few weeks were over 50,000 units for the Powerwall (US$179 million), and 25,000 units for the Powerpack (US$625 million), therefore combined orders of US$800 million.

During the first quarter of 2016, Tesla delivered over 25 MWh of energy storage to customers on four continents. Over 2,500 Powerwalls and nearly 100 Powerpacks were delivered in North America, Asia, Europe, and Africa. As of October 2016, nearly 300 MWh of Tesla batteries had been deployed worldwide.

Powerpack

At the announcement, a larger battery called Powerpackâ€"storing 100 kWh of electrical energyâ€"was projected to be available for industrial consumers, reaching a price point of $250/kWh. The Powerpack was projected to comprise the majority of stationary storage production at Gigafactory 1 while Powerwall would play a smaller part, giving Tesla a profit margin of 20 percent.

Price tendency

In September 2016, Tesla priced the Powerpack at $445/kWh, and a system with 200 kWh of energy and 100 kW of peak power was the cheapest available priced at $145,100. A bi-directional 250 kW inverter costs $52,500. By October 2016, a limited system of Powerpack 2 cost $398/kWh.

Volume tendency

Musk predicted in 2016 that the utility power will need to increase to supply more electric vehicles, eventually reaching an equilibrium with about 1/3 of power coming from distributed energy and 2/3 from utilities. Battery storage is one of the ways to mitigate the increasing duck curve, particularly in California.

Return on Investment Calculations

A May 2015 article in Forbes magazine calculated that using a Tesla Powerwall 1 model combined with solar panels in a home would cost 30 cents/kWh for electricity if a home remains connected to the grid (the article acknowledges that the Tesla battery could make economic sense in applications that are entirely off-grid). US consumers got electricity from the power grid for 12.5 cents/kWh on average. The article concluded the "...Tesla's Powerwall Is Just Another Toy For Rich Green People." Bloomberg and Catalytic Engineering magazines also agreed that the Tesla system was most useful in places where electricity prices are high.

There are however a number of such locations, including Hawaii and other remote islands that generate electricity with shipped-in or flown-in fuels. However, some of these locations, such as the Canadian high Arctic and isolated native reserves, have cold climates where battery technology often fails to perform as well as more moderate climates.

The Swiss bank UBS said that the Powerwall makes sense in Australia and Germany where electricity is very costly but solar panels are well distributed.

As of November 2016 cost of installation for one Powerwall 2 starts at AUD $2,950 in Australia or $1,600 in USA

Example for Installation of Powerpack

Tesla installed a grid storage facility for the Southern California Edison with a capacity of 80 MWh at a power of 20 MW between September 2016 and December 2016. This means that the storage unit (1/2017) is currently one of the largest accumulator batteries on the market. Tesla installed 400 Powerpack-2 modules at the Mira Loma transformer station in California. The memory serves to store energy at a low network load and then to feed this energy back into the grid at peak load. Prior to this, gas-fired power stations were used. (see also Battery storage power station)

Competition

Home

Energy technology company Enphase Energy, based in California, has announced it will release its lithium iron phosphate battery as part of a complete alternating current Enphase Home Energy Solution starting in Winter 2016 in Australia and New Zealand with Genesis Energy conducting trials. The system, which includes monitoring and control of solar generation, home energy consumption and battery storage, will be sold at wholesale through solar distributors, who sell to solar installers. Enphase's modular 'building block' batteries are more efficient than the Tesla Powerwall (96% compared to Tesla's 92% round-trip efficiency). The Enphase AC Battery also includes an inverter inside the casing, and works with all existing solar systems, or alternatively in homes without solar. Lithium iron phosphate batteries are known to be the most stable and safe of the various lithium batteries.

Mercedes-Benz / Daimler AG announced in June 2015 that they would be selling batteries for domestic or commercial use by the end of 2015. These would compete against the Tesla Powerwall and would be marketed by Deutsche Accumotive, the Daimler subsidiary that produces the Lithium-ion battery that Mercedes uses in its electric and hybrid cars. Several other solutions are available.

Industrial

BYD's energy storage system is another competitor of Tesla's Powerpack. UC San Diego installed this system which has 5 megawatt-hour (MWh) capacityâ€"enough to power 2,500 homesâ€"in September 2014. BYD is a large supplier of rechargeable batteries, and is also known for its leading position in electric buses.

Sonnen and AutoGrid collaborates on combining house batteries into a large scale utility-level grid storage system.