UNIVERSAL STUDIOS, Calif.—On Friday evening Tesla officially announced an integrated solar roof and Powerwall product for individual use. When or if the roof and the Powerwall become available to consumers is most likely contingent on Tesla and SolarCity investors voting to approve Tesla's offer to buy SolarCity in a $2.6 billion (£2.1 billion) all-stock deal on November 17.

Tesla set up an elaborate "neighborhood" display on the Universal Studios lot in Los Angeles. The company unveiled several model homes with Tesla Powerwalls mounted on the side and a variety of custom roofs with photovoltaic cells disguised as tiles.

"You really need to make solar panels as appealing as electric cars have become," Tesla CEO Elon Musk told a crowd of several hundred people as the sun set on the artificial neighborhood. "The goal is to have a roof that's less than the installed cost of a roof plus electricity."

In a private conversation with journalists after the announcement, Musk declined to state a price for the roof or a price-per-square foot. He did admit "it's not gonna make sense for somebody to replace a brand new roof with a solar roof." But if your roof needs replacing anyway, he said, the cost/benefit could make sense for many families.

Tesla and SolarCity representatives said they expect to start installing roofs as early as next summer.

Tesla

Megan Geuss

Megan Geuss

Megan Geuss

Tesla

Megan Geuss

Megan Geuss

In response to a press question, Musk said that if the merger with SolarCity isn't approved, such a collaboration could become "unwieldy" and would make much less sense to continue. "Any time there's any collaboration between SolarCity and Tesla, we have to run things between independent board committees," Musk added.

Tesla and SolarCity admitted that, currently, the solar roof tiles are estimated to have 98 percent of the efficiency of a more traditional solar roof. But Musk hinted that Tesla's goal is to make the tiles more efficient than traditional solar panels "because the photon goes in and bounces around" behind the tile glass.

Musk also said the tiles are incredibly durable, and he showed a marketing video of a weight crushing traditional roof tiles while leaving a solar roof tile undamaged. Speaking to the press, the CEO said that he expected the tiles to have "two to three times the longevity of asphalt" in terms of wear and tear. Musk implored the audience to compare the roof tiles to the wear one sees on cathedrals: "the roofs don't last, but the stained glass does," he said.

Tesla executives said they'd likely start out offering one or two kinds of tiles, but eventually the company would offer four kinds of tiles–Textured Glass Tile, Slate Glass Tile, Tuscan Glass Tile, and Smooth Glass Tile.

Eventually, the solar panels would likely be built in the Buffalo, NY, solar panel factory that SolarCity has been working on for some time. The SolarCity factory has been compared to Tesla's Sparks, Nevada, lithium-ion battery factory (called the Gigafactory) in scope and ambition. Earlier this month, Tesla promised to partner with Panasonic on the Buffalo facility to produce solar panels. Panasonic has been Tesla's manufacturing partner for the Gigafactory as well.

The bigger news is Powerwall 2

Tesla announced its first stationary storage battery in May 2015. In the week after the announcement, Tesla Energy racked up 38,000 preorders for the announced 7kWh daily cycling and 10kWh emergency battery. Tesla later killed the 10kWh battery in favor of the 7kWh daily cycling battery, which the company felt would be more appropriate for consumers who wanted to store energy from their solar panels and use that energy in the evening. Roll out of the stationary storage batteries has been slow, in part because Tesla had been waiting on the first portions of the Gigafactory, where the stationary batteries are made, to come online.





But tonight Musk announced Powerwall 2, which will have 14kWh of storage and 5kW of continuous power at a $5,500 (£5,500) price point. Tesla claims that's enough to power lights, sockets, and a refrigerator in a four-bedroom house for a day. Powerwall 2 will be guaranteed to work for unlimited cycles over 10 years. In the UK, Powerwall 2 installations begin in February 2017; in the US, installations begin in January 2017.

According to Tesla press materials, the Powerwall 2 is a great deal more advanced than the first generation, with a "liquid thermal control system, an integrated inverter, and software that intelligently dispatches electricity when it's needed most." The battery software will allow the owner to load-shift in addition to powering a house when solar panels aren't experiencing sun. In other words, a Powerwall 2 owner could discharge the battery as electricity becomes more expensive from a utility during heavy use periods.

Musk insisted that a solar roof and Powerwall combination wouldn't be the death of utilities because electricity demand would increase by up to two thirds more to account for the rise in battery-powered transportation and electric heating. Meanwhile, solar roofing would only absorb a third of that total electricity demand.

Utility-grade batteries

Tesla

Tesla

Tesla also has a burgeoning industrial-use battery business. The company sells Powerpacks to companies, and lately it's won contracts to install stationary storage on a megawatt scale with two utilities: Southern California Edison and Kauai Island Utility Cooperative. The batteries would ideally "smooth out" peaks and valleys created by intermittent renewable energy sources in the utilities' power supply, allowing the utilities to delay turning on extra generators.

The Powerpack also got an upgrade today. Apparently, that upgrade comes with twice the energy density of batteries in the first version of the Powerpack, as well as a brand new inverter that's manufactured at the Gigafactory. "It is the lowest cost, highest efficiency, and highest power density utility-scale inverter on the market," Tesla wrote in a press statement.

The company added that buying Powerpacks would be cost-competitive with other output-related solutions for utilities, including building more substations or bigger wires. When Ars spoke to companies using Powerpacks last year, the companies cited Tesla's battery control software as an advantage in their decision to incorporate batteries. Now, Tesla says the Powerpack's software and interface have improved, "allowing for better energy management and dispatch."

Ultimately though, the consumer-facing products, especially the solar roof, will likely guide the conversation about Tesla's continued push to build a electricity ecosystem. "You'll want to call your neighbors over and say 'check out this sweet roof'" Musk told the audience as the sun disappeared behind the horizon.

Update: Ars replaced two cell-phone shots with press images, and added an extra press image.