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Why Tesla's New Solar Roof Tiles and Home Battery Are Such a Big Deal (techcrunch.com)
On October 28th, Tesla founder and CEO Elon Musk unveiled the residential "solar roof," consisting of glass roof tiles with integrated solar panels. Not only are they more durable than traditional roof panels, but they offer efficiency that is 98 percent as good as traditional, photovoltaic panels. The company also announced the Powerwall 2, a home battery that can store 14 kWh of energy, with a 5 kW continuous power draw, and 7 kW peak. It's designed to store the energy from the solar roof during day to power your home at night. Darrell Etherington via TechCrunch explains why these solar roof tiles are such a big deal: It's easy to dismiss the aesthetic import of how Tesla's tiles look, but it's actually important, and a real consideration for homeowners looking to build new homes or revamp their existing ones. The appearance of the tiles, which come in four distinct flavors (Textured Glass, Slate Glass, Tuscan Glass and Smooth Glass) is going to be a core consideration for prospective buyers, especially those at the top end of the addressable market with the disposable income available to do everything they can to ensure their home looks as good as it possibly can. As with other kinds of technologies that are looking to make the leap from outlier oddity to mainstream mainstay, solar has a hurdle to leap in terms of customer perception. Existing solar designs, and even so-called attempts to make them more consistent with traditional offerings like the above-mentioned Dow Chemical project, leave a lot to be desired in terms of creating something that can be broadly described as good-looking. Tesla has been referred to as the Apple of the automotive world by more than a few analysts and members of the media, and if there's one thing Apple does well, it's capitalize on the so-called -- halo effect. This is the phenomenon whereby customers of one of its lines of business are likely to become customers of some of the others; iPhone buyers tend to often go on to own a Mac, for instance. For Tesla, this represents an opportunity to jump-start its home solar business (which it'll take on in earnest provided its planned acquisition of SolarCity goes through) through the knock-on effects of its brisk Tesla EV sales, including the tremendous pre-order interest for the Model 3. Tesla's solar tiles claim to be able to power a standard home, and provide spare power via the new Powerwall 2 battery in case of inclement weather or other outages. Musk says that the overall cost will still be less than installing a regular old roof and paying the electric company for power from conventional sources. But Musk's claims about the new benefits of the new solutions don't end there. Tesla's tiles will actually be more resilient than traditional roofing materials, including terra-cotta, clay and slate tiles. Solar roofing, Powerwall and Tesla cars taken together represent a new kind of ecosystem in consumer tech, one that carries a promise of self-sufficiency in addition to ecological benefits. Tesla has already tipped its hand with respect to how it intends to make vehicle ownership a revenue generator for its drivers, rather than a cost center.
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A few things.
First, 5kw is a quarter the normal service normally provided. We have a 20 kw drop; that's normal. It's not about what you use normally, either, it's about the toaster, the vacuum, the frig, the freezer, the AC, etc. all kicking on at once. It happens -- don't think it doesn't. That's why there's a 100 amp main system breaker in your typical breaker box. 100 amps at 240 volts. 5kw is about 25 amps at 240 (yes, you almost certainly have a 240 system... there are two 120v legs, and some stuff in the house is on one, and some stuff is on the other. A few things -- dryers, electric stoves, AC systems, things like that -- are on both legs and actually use 240.)
Second, that battery... that's an expensive component, and one with a decidedly limited lifetime. There's going to be an ongoing maintainance cost there, and you should factor it in if you aren't just going to be compulsively home-swapping. Same with current EV designs, for that matter.
Third, watch out for microinverter-based designs. These place small inverters all over the solar cell system, typically one every panel or every few panels (in this case, it would X number of tiles, if it's a microinverter design.) Every installation that uses them that I've come across thus far is a horrific generator of radio frequency interference. It'll do everything from reduce your wifi and bluetooth ranges to blow out your AM and FM reception and anything else going on that actually uses, you know, radio. A quality installation has a central, single, high-quality, high-power inverter. Those shitty little "we do solar power cheap!" companies... there's a very good reason they're cheaper. Because the stuff they install is crapola.
All you want coming from the roof / panel farm is well-filtered DC. Period.
I would hope, given the size of the energy conversion systems in their vehicles, that they didn't go that way, or, that they broke new ground and built quality systems that are actually RF quiet. But it's something to keep in mind until we know more about these proposed systems.
I've fallen off your lawn, and I can't get up.
The grid operator/utility doesn't actually do business with the home owner. Home owners are too small for the effort involved. What the grid operator does business with is called an aggregation entity (Solar City etc). This is why the home owner still buys power at silly low rates.
The aggregation entity does all the accounting and sells the energy the homeowner doesn't use or store to the grid operator at rates mandated by regulatory agencies. The sell rate to the home owner NOT regulated in any way, only the sell to the grid.
That same entity is also involved in what are called rate up/rate down events. This is where the entity get's paid for being able to supply energy during peak loads OR more importantly absorbing and storing energy during excess generation periods. This is why the system having storage is important. Also of note, the home owner does NOT participate is revenues derived from rate up/rate down events.
DC filtered from what if there are no inverters?
With small tiles that's a lot of wires even if several panels are connected in series.
There are other benefits of micro-inverters, such as maximizing power generation per-panel and panel health monitoring.
Besides to make a "quiet" powerful inverter it takes a lot of capacitance that is localized in single device. Costly repair?
There are compromises both ways.
4wdloop
Shingles get removed from my residence by wind.
What I find interesting about "alternate" roof materials is their failure modes. When a metal roof fails it fails along predictable seams and both maintenance and mitigation are much, much simpler than with a traditional wood/asphalt roof. It also doesn't catch fire when flaming debris falls on it. On that basis alone, asphalt roofs and indeed wooden roof trusses and covering should be illegal. Every building code in the nation, right now. That's an embarrassingly flammable shit-show and we have had the technology to fix the problem for over a century.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"