Tesla Sees a Solar-Powered Future—But Can You Afford It?

Musk revealed at a Universal Studios press event last week a collection of solar roof tiles designed to look like traditional roof building materials. A cul-de-sac of houses on the set used to film the show Desperate Housewives were renovated to showcase Tesla's new photovoltaic building materials, which are as attractive as they are functional, and available in a range of architectural styles: smooth glass, textured glass, French slate, and Tuscan ceramic. Viewed remotely during the event webcast, it wasn't obvious that these were solar-powered homes—and that was the point. If you want mass adoption of something, you have to make something that people actually want.

Solar tiles have been around for years, although this type of building-integrated photovoltaic (BIPV) system represents only one percent of world-wide PV installations. Like with the Tesla Roadster and the award-winning electric vehicles that followed, Musk isn't unveiling something new; rather he's making an iterative improvement to existing technology. After all, it takes a certain architectural sensibility to embrace solar panels perched on roofs and mounted to the exterior siding—not to mention a generous amount of talent to make them stylish. (Some home owners associations of planned communities have gone so far as to ban them from use if they can be seen from the street.) What Tesla has done with these solar tiles is to remove one of the biggest hurdles to mass adoption: their, um, polarizing aesthetics.

A digitally printed glass exterior obscures the solar energy-absorbing photovoltaic cells from view. Like natural products, each manufactured tile is unique (smooth glass tiles excepting), ensuring no two roofs look exactly the same, and avoiding the cookie-cutter look of tract homes. In the U.S., four to five million new roofs are installed every year, according to Tesla; using this new material, entire neighborhoods will transition to renewable energy, which is crucial to reduce the increased burden being placed on utility companies as more vehicles swap oil for electricity. The best part, says Musk, is that solar tiles will cost less than the real thing.

To be clear, these tiles are still not as energy-efficient as full solar panels, but when used in conjunction with the new 14kWh Powerwall 2 with a 7kWh output (scalable up to 9 units), they have the capacity to power an entire house, according to Musk. At night, homes would feed off the Powerwall 2, and ideally, recharge the Telsa vehicle parked in the garage.

After sharing this information, Musk rhetorically asked the crowd, “Why would you buy anything else?" Well, it still comes down to money.

The 14kWh Powerwall 2 will retail for $5,500, and until the Model 3 is released some time next year, you're looking at anywhere from $60,000 to $135,000 for an electric car from Tesla. The cost of solar materials has come down drastically in recent years, but they’re still a significant investment, and one that isn’t quickly recouped. However, Tesla is hoping that, by creating a solar ecosystem for the home that helps offset everyday energy consumption and provides a free and zero-emissions source of fuel for electric cars, mass adoption will follow.

Actual facts and figures about Tesla's solar roofing material are scarce—pricing, availability, and installation costs weren’t announced at the launch event—but some rough numbers can be found online.

The rule of thumb that many solar contractors use is that photovoltaic systems cost $1.50 per watt for the panel, and $1.00 for installation. However, Energy Sage reported the average price for a home PV system is $3.57 per watt installed.

Estimates for solar shingles are harder to find, mostly because they're not often used. According to freecleansolar.com a 3kWh system using solar shingles would cost $15,000 to $20,000, which covers approximately 600 sq. ft. An average two-story, three-bedroom, two-bath home is around 1,500 sq. ft..

Using these figures to plan a solar shingled roof renovation is difficult, because materials and associated costs vary greatly. But covering a roof end-to-end would be expensive—and likely inefficient since many roofs have steep pitches, angles, and areas that may be shaded. Material choice affects roofing estimates, which are also based on location, laborer skill, roof layout, and the quality level a homeowner wants to achieve. Assuming a 1520 sq. ft. roof with a low slope and "value grade" (one step above "builder grade") construction quality, Homewyse provides these low- and high-end estimates:

Clay tile:

ttt$20,796.58

$29,371.00

Slate tile:

$20,367.64

$28,729.53

Wood shingle:

ttt$11,036.38

$15,162.88

Because there is no pricing available to date, it's not possible to tell if Tesla solar tiles are more or less expensive than traditional rooming materials. A federal tax credit of 30 percent of the PV expenditures for homeowners is available until 2019, and then gradually steps down over the next few years. State credits may further reduce these expenses. Free solar energy may also offset costs. Energy bill averages vary from state to state, and using 2009 census data, the U.S. Energy Information Administration shows a national average $2,024 spent on energy per household. Over 10 to 20 years, a homeowner could greatly offset or fully recover costs of solar roof renovations, assuming 100 percent of energy consumptions is covered by the BIPV system.

However, Musk may not be accurate when he says that the company's products will last longer than traditional building materials. Wood tiles have a life expectancy of 30 years, and clay and slate tiles can last 60-100 years.

Although no one says you have to purchase the entire Tesla trifecta all at once, that's certainly the rationale for merging Solar City and Tesla together. By creating a one-stop shop and vertical solution, perhaps more people will consider integrating solar into their renovation and building projects. Moreover, it's an energy-efficiency model that will work in any region regardless of the existing infrastructure. The real question is, can you afford it?

For the average homeowner, the answer is mostly likely a sound "no," at least until costs come down. But that may happen sooner than later: The average price for solar energy installations is expected to fall to $1.50 per watt by 2020. In the meantime, at least these materials will spark interest in solar roofs when homeowners previously may have dismissed the them as a fugly, expensive upgrade.

But if you ask Musk, he'll probably answer that the world can't afford not to.