What do we know about Tesla's solar shingles?
Excitement is high but details remain scarce.
Perspective solar customers and solar professionals eagerly awaited Elon Musk’s unveiling of Tesla’s Integrated Solar Roof in late October. Major media sources covered Tesla’s event and reported Musk’s claim that the integrated solar roof would last longer and cost less than a traditional roof. Although visually appealing, important doubts remain about the roof, such as its price and energy production. It’s likely that solar contractors will receive questions and inquiries for the Tesla Solar Roof, but with the little Tesla has told us about the product and the history of BIPV (building-integrated photovoltaics), it is difficult to confidently endorse Tesla’s product. Here's what we do know:
Two important doubts about the Tesla roof are the efficiency and costs. It is assumed the product will be BIPV, which has historically been 2% less efficient and generally 20% to 50% more expensive than crystalline modules. The roof is also estimated to produce less energy than traditional modules because BIPV experience increased heat loss and does not provide a solution to sub-optimal roof angles and orientation. Most importantly, BIPV has been a tough product to introduce successfully to the market. Established and well-financed companies such as Dow Chemical and BP have attempted to launch similar products in the past but ceased production. In the next 18 months, Tesla will need to prove that it will deliver a product that addresses BIPV’s cost and efficiency challenges.
Tesla has also not sufficiently explained the installation and interconnection process. There will be significantly more labor required than a traditional PV and roof install because of the wiring; this means the labor costs will undoubtedly be higher. We also do not know how AHJ’s and fire departments will react to this product for rapid shutdown compliance (NEC 2014), which will be in most states by the end of 2017. Tesla has not provided any information about the product’s O&M, warranty, or if there will be financing available from Tesla/SolarCity or another entity. In many jurisdictions (even with high solar penetration) navigating the AHJ and interconnection process is a difficult and expensive process with traditional residential PV systems. It is unclear how AHJs will respond to Tesla’s product which could lead to delays, added paperwork and costs to installs.
Tesla estimates that in two years this product will have 5% market share of the 4 to 5 million annual new roofs, which is about 225,000 homes and 1,300 MW (average 6 KW per home). In 2015 SolarCity installed 870 MW and Tesla/SolarCity has not explained their business model for the integrated roof. It is unclear if Tesla will do the sales and installation by leveraging SolarCity or if will they distribute the shingles to roofers. Tesla could also partner with leading home builders such as KB Homes, Petersen and Dean, or Lennar, but no such partnership has been announced as of yet. However, they haven’t developed a profitable company selling, installing, and financing solar, so why will this be different?
The Tesla solar roof has the best aesthetics from a BIPV or PV product. While aesthetics matter, Tesla needs to address fundamental issues such as cost and output before prospective solar customers can even consider purchasing this product. Furthermore questions such as "what will this product do to the home’s insurance, resale value, or mortgage?" remain unanswered. Given the product’s uncertainties and the rapidly improving economic benefits of traditional PV, solar contractors should remain confident that their installs will remain competitive and provide their customer's more value than the Tesla Integrated Solar Roof for years to come.
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