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SolarRoof.Cool — A crash course on Tesla's Solarglass roof, Powerwall, and sustainable energy systems, from the perspective of an owner.
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- Title
- The Tesla Solarglass Roof and Powerwall - SolarRoof.Cool
- Authors
- Alex Guichet
- Word count
- 9080 words
This is my latest huge creative project—documenting everything about my experience with the Tesla Solarglass roof.
I think it's a super cool source of renewable energy. It's may not be the right solution for everyone, but it's already great—and I'm sure the tech will get better with time too. I'm excited to be an early customer of it—and will happily answer any questions.
As a fun bit, I reverse engineered bits of the Tesla App API for this, so you can see realtime data from our solar roof + powerwall.
Thank you so much for sharing your experience, in a well-designed, highly informative site with a nifty data feed.
I love it when people testing at what's effectively alpha or beta development stage are sharing their feedback.
I've had an eye on the Tesla solar home projects for a while. Florida had stupid laws (electric utilities, regulatory capture, blah blah) that just wouldn't have made solar economics work well for us under any circumstances, and Michigan... well, I'm not sure what technical options the solar tiles offer for heavy snow. I'll do some homework on whether there are self-heating options.
We'll need a new roof in a couple of years, we're already tussling about whether the garage needs a 240v circuit, so you can guess that we're ready for the Tesla systems to reach more general use.
Solar works under snow! Though...I'm not actually sure what the diminishing rate of return is.
We talked with a local solar installer at a home show recently and were advised that there are newer options for dealing with snow; the power requirements and efficiency loss aren't huge. What I don't know is whether a solar tile system could accommodate something like this.
In any case, most of the local electric utility service is solar anyway, so it's not a compelling economic or conservation case for us.
This is extremely cool! Thanks for sharing.
Cool site, cool roof.
Can you elaborate on this quote from your site?
Is this some kind of regulatory thing?
If you didn't have enough solar generation capacity (in winter, for instance), wouldn't it be sensible to use the grid during non-peak usage periods to top off the Powerwall(s) to get you thru the peak periods w/o using grid power?
Is this something you're not allowed to do?
ETA: I kept reading .... You may have answered this further down the page. Is this just a tax incentive rule?
Whatever the source, is there some logic behind this, which I'm failing to grasp? Or is this just a dumb rule?
ETA2: Former roofer here .... Minor quibble, looking at the install pics now. It looks to me like the underlayment they added was not plywood, but rather OSB (oriented strand board). It is cheaper and lower quality than plywood — but absolutely fine for roof underlayment.
ETA3: I just finished reading. Dude. Seriously, nice job documenting this whole thing. Great site.
Sorry, I'll update that on the site to clear the ambiguity: it's a tax thing. If you want to get the 30% (now 26%) tax credit on this installation, the battery cannot be used to charge from the grid.
I don't think I've fully made up my mind if I agree with it or not. Mostly because, if this tax credit didn't exist, I think there would be another crazy rule blocking this. (It feels like you should be able to top up for your use.) I am still so new to this whole world that I haven't done much boundary pushing on this edge of my knowledge.
Thank you for this clarification. TIL!
This is really awesome. You've put in a lot of effort and it shows :)
I already commented once, extensively, on the site overall.
This is directed at the Duck Curve.
If a person did power arbitrage as you mentioned ... completely forgo the solar element, and instead just installed 4, 6, 20 PowerWalls with the explicit goal of fully charging them during off-peak hours, and then using them to power his home, plus feed back the extra to the Grid during high demand hours ...
I mean, wouldn't that individual financial strategy, incentivized across a utility's territory, be a perfect solution to the Duck Curve issue?
Is this strategy financially viable there (you're in California, right?)? If not, why not?
And on a semi-related note, if you're tempted to cut away from the Grid entirely, investigate the potential of a stand-alone electrical co-op ... 5-50 off-grid neighbors, with 2–5 of them configured like I just described above, as the community storage back-ups. It would be more complicated, both technically and legally, but it would also be much more feasible, economic, and efficient, than trying to go fully off-grid alone.
This is a super valid question, and you're kinda hitting on some things that exist! (It's sort of non-viable-ish for regular consumers to just casually do on their own.)
First, addressing price arbitrage in general: (At least in California) Net Energy Metering allows you to buy and sell energy at retail prices. The contract has a bunch of restrictions, but typically your energy storage has size restrictions to be more-or-less home-scale.
Next, the closest real-world example to what you explain is a virtual power plant. The execution varies in a lot of projects, but for energy storage it typically works out as deep subsidies to buy your batteries, but the "virtual power plant" owner (the one in control/sourcing the funding for your subsidy) gets to have full control of a few kWh of your battery to sell back when they see fit.
There is also another great example of this at massive scale: the Hornsdale Power Reserve. It's the fabled "tesla big battery" (even though they're only the supplier, not the operator), but it's an interesting example because it exists on its own just for price arbitrage. At wholesale prices, it charges itself when power is cheap, and sells the stored energy when its expensive. It's fun to read about, because if I had the money I'd totally build this as a business.