Solar Roof Tiles
Elon Musk has been generating lots of PR about Tesla/SolarCity's getting ready to sell solar roof tiles (sometimes called solar shingles). But at the end of May 2017, it's still vaporware. The real specifications haven't even been released. Manufacturing hasn't started yet. Yet some people are naturally starting to wonder whether it might make sense to wait for them to become widely available, rather than to purchase a solar-panel system.
There's nothing new about solar roof-tiles. Dow Chemical offered their Powerhouse brand for five years, before quitting the solar-tile business in July 2016. CertainTeed still sells their Apollo II tiles, while SunTegra, Atlantis Energy Systems, and Lumeta Solar all continue to offer their own brands. None has been very successful, for reasons that will be explained.
The potential advantages of solar roof-tiles over solar panels are primarily aesthetic. Although solar panels can be mounted flush with a tile roof and nearly flush with other roof types (instead of sticking way up on racks, as low-quality installations often do), solar tiles can be absolutely flush with any roof surface. Unlike panels, they can be made to look similar to existing roof shingles or tiles, although not identical (they will still be much shinier, for example). They can replace a portion of your actual roof or even all of it, rather than requiring sound roofing underneath, as panels do.
But their drawbacks are many and serious. They are very inefficient. Tesla's, for example, produce less than a third of the electricity per square foot than the most efficient solar panels do.* That means you need more than three times as much roof space for them as you would for efficient panels. They don't work at all on flat roofs, and roofs with little slope suffer lower output than with panels, because solar tiles must match the pitch of the roof.
They are likely to cost at least 50% more per watt than even the most expensive panels. Even if you have to replace the portion of your roof under a new solar-panel array, solar tiles would be far more expensive. Part of their installed cost may not be eligible for the ITC (Investment Tax Credit). They are very heavy and may require additional support components that will increase cost of installation. Replacing them as they age, degrade, or fail will be more expensive than replacing panels.
Getting them from Tesla could take years. Musk says it could be 5-10 years before they become widely available. By that time, the ITC could be gone. (It is currently scheduled to expire in 2023.) Tesla's tiles' long-term output, production, rate of degradation, reliability, and durability are completely unknown. And neither Tesla nor SolarCity is a roofing contractor, which requires very different skills than installing solar panels.
All in all, few experts see solar tiles as a good alternative for solar panels, at least for years to come. They would be worth considering only if you like their look so much better than the most attractively installed panels, you're going to replace your entire roof with solar tiles, and you can live with all the drawbacks known and unknown at this time.
There's nothing new about solar roof-tiles. Dow Chemical offered their Powerhouse brand for five years, before quitting the solar-tile business in July 2016. CertainTeed still sells their Apollo II tiles, while SunTegra, Atlantis Energy Systems, and Lumeta Solar all continue to offer their own brands. None has been very successful, for reasons that will be explained.
The potential advantages of solar roof-tiles over solar panels are primarily aesthetic. Although solar panels can be mounted flush with a tile roof and nearly flush with other roof types (instead of sticking way up on racks, as low-quality installations often do), solar tiles can be absolutely flush with any roof surface. Unlike panels, they can be made to look similar to existing roof shingles or tiles, although not identical (they will still be much shinier, for example). They can replace a portion of your actual roof or even all of it, rather than requiring sound roofing underneath, as panels do.
But their drawbacks are many and serious. They are very inefficient. Tesla's, for example, produce less than a third of the electricity per square foot than the most efficient solar panels do.* That means you need more than three times as much roof space for them as you would for efficient panels. They don't work at all on flat roofs, and roofs with little slope suffer lower output than with panels, because solar tiles must match the pitch of the roof.
They are likely to cost at least 50% more per watt than even the most expensive panels. Even if you have to replace the portion of your roof under a new solar-panel array, solar tiles would be far more expensive. Part of their installed cost may not be eligible for the ITC (Investment Tax Credit). They are very heavy and may require additional support components that will increase cost of installation. Replacing them as they age, degrade, or fail will be more expensive than replacing panels.
Getting them from Tesla could take years. Musk says it could be 5-10 years before they become widely available. By that time, the ITC could be gone. (It is currently scheduled to expire in 2023.) Tesla's tiles' long-term output, production, rate of degradation, reliability, and durability are completely unknown. And neither Tesla nor SolarCity is a roofing contractor, which requires very different skills than installing solar panels.
All in all, few experts see solar tiles as a good alternative for solar panels, at least for years to come. They would be worth considering only if you like their look so much better than the most attractively installed panels, you're going to replace your entire roof with solar tiles, and you can live with all the drawbacks known and unknown at this time.
