Those wacky kids at Tesla have solved the energy crisis (again). In April, you too will be able to order Tesla’s new solar roof tile, and then all of your problems will disappear. Even better, according to Elon Musk, these new roof systems won’t cost any more to install than a regular roof!
Now dear reader, it is a known and established fact that I am a grouchy bastard. So it should come as no surprise that my brow wrinkles in consternation and my face twists into a sneer of derision at such lofty claims from our savior. Can his words be true? Can I get a 6,8,10 kW solar system installed on my house for the same price as a a regular old roof? If I am going to retain any credibility, I need to be fair about how I approach this. If Mr. Musk had truly accomplished this feat, then honor demands that I acknowledge it.
So I suppose it is a good thing that he likely hasn’t. The Tesla Solar roof tile is sold alongside their proprietary home battery system, which will whack another 7-to-10k onto the cost of the tiles. he never mentions this in the tweets. But if that was the whole of the issue, it would not be insurmountable. Storage + Solar PV is always a good idea. Because the sun doesn’t shine at night, and sometimes I want to have power at night. But there is more sly misdirection than that to deal with.
All of Musk’s comparisons are to ceramic or concrete roofing systems’ supply chains. You know; the ones that cost more than you and I can afford?
I can put an asphalt shingle roof on a house for about $1 a square foot (if we don’t have to rebuild the roof entirely). If we use an established solar shingle cost of $3/watt installed, then we get about $59/sq foot (19.6W per 1-foot panel). Keep in mind, Tesla really just bought out Solar City’s roof tile business, and Musk has already described efficiencies that are no better than previously existing solar roof tiles, so we are unlikely to see any huge improvements in either production costs or installation costs.
One dollar per foot versus sixty. That’s the reality. Yet Tesla had no problem with claiming:
“So the basic proposition will be: Would you like a roof that looks better than a normal roof, lasts twice as long, costs less and—by the way—generates electricity? Why would you get anything else?” -Elon Musk
Look at that phrasing. He said “normal roof.” Less than 15% of the roof real estate in the US employs concrete or ceramic roof tiles, which are the only products his tile has a prayer of competing with on price. He put real thought and effort into getting as close to lying as one can get without actually lying. It’s an intentional misdirection and the sort of bad acting that makes our industry so difficult to work in.
Now let’s talk about production. Roofs for most buildings are designed to be sacrificial. This means they degrade over time as they are what gets the brunt of mother nature’s wrath. In New England we get snow and ice for half the year. In the Midwest it will be wind and hail in the summer. The deep southeast will have punishing hurricane seasons and the southwest, well, as long as the panels don’t overheat they’ll probably be OK. The Northwest doesn’t get enough sun to make a solar panel all that interesting anyway. Do you have tall trees nearby? Which direction does your roof face? Getting good production out of a solar installation means controlling a lot of variables. Variables that you will have very little control over when you use your own roof as the array.
I’ll speak for my home region. I predict that a brand-new Tesla super-roof installed on a typical new England home will have decent production for the first couple of years (if you can keep the snow off of it), and then production will shrink fairly sharply after that. How do I know this? Because regular roofs made of regular roof stuff do this. Materials designed to survive under these conditions start to degrade year over year and pretending there is something magical about a crystalline solar panel that prevents this is just silly.
So the unvarnished reality of a solar roof looks more like this:
A very expensive super-premium product will generate passive cash flows that will very greatly with location, while following a predictable degradation and deterioration process over their rated lifespan.
My gripe here is not with solar PV. If you like it and can afford it, go ahead and get it. Sunlight is free and free fuel is nice. But by the icy countenance of Ymir, tell the f&4k!%g truth when you sell it! Tell the customer that what they are buying is expensive and may not perform as well as one might like. Do your best to put together a fair and realistic proposal and let the customer decide what they are comfortable with.
Don’t even get me going on all the people whole will blame “Big Oil” when the costs of these roofs are prohibitive and no one buys them. “Big Green” was the one who deceived us in this case, let’s have the integrity to admit that up front. Then we can see about fixing the problems with our industry.