What are your thoughts on the new Tesla solar roof tiles? originally appeared on Quora: the place to gain and share knowledge, empowering people to learn from others and better understand the world.Answer by Michael Barnard, low-carbon innovation analyst, on Quora:
I have a few thoughts about the new Tesla solar roof tiles:
Musk is exactly right that making solar panels look gorgeous and integral with the existing look and feel of homes is critical to the growth of home solar. People love their homes and obsess about them. Having multiple choices of very attractive tiles which look good longer and don’t fade is excellent. Tesla’s choices appear to be better than any existing solar tiles on the market.
Musk is right that in many places that the cost of the roof, plus the electricity it produces, plus the purported longevity of it, will make the overall cost of the solution cheaper than a normal roof and getting electricity from the grid. However, the roof itself is undoubtedly going to be quite a bit more expensive than a normal roof based, so amortization of the price is going to be critical somehow. But electricity prices vary widely across geographies, so it won’t make sense everywhere.
Musk’s suggestion that a third of energy will come from rooftop solar and two-thirds from the grid is off I think. Only about 25% of households are situated and oriented in ways that provide useful solar exposure according to the EIA or NREL (I forget which). I crunched the numbers and only large, detached, ranch-style, southern US homes could generate enough electricity to provide the full years needs. Office, condo and apartment buildings have a lower roof surface area compared to interior volume and usually have window washing, elevator mechanicals and/or HVAC on the roofs which diminishes available surface even more. Only big box stores, warehouses, casinos and the like have particularly high roof surface areas to interior volume ratios. It’s more likely that distributed solar will support only 10% of electrical demand. That’s good, but not 33%.
Musk glossed over the two electric cars in every garage scenario in the video when he was talking about demand. Normal patterns are for cars to be away from homes during peak solar periods and the PowerWalls hold less than 20% of a Tesla car’s battery and pump electricity way too slowly to charge a car. Basically, you still have to be plugged into the grid to charge your cars, which is fine, but the video downplayed that a lot. Like point three about the actual percent of electricity likely to be provided by rooftop solar, there’s an implicit overstatement in the video.
More urban densification is occurring globally. Fewer people are living in detached homes with big roofs as a percentage of people. The tiles are gorgeous, but the demographic for them is growing more slowly than the population. It’s kind of targeting a slow growth market, which is a challenge. Utility solar is a much faster growth market, as are automobiles.
I think the 2% degradation due to the decorativeness of the tiles might be an understatement. That 2% is likely when the sun is perfectly aligned at 90 degrees to the tiles where the peekaboo louvers allow the most light through. The sun will rarely be perfectly aligned and roofs are only coincidentally well aligned with the sun. I’d expect a higher degradation in actual use compared to normal solar panels. This might or might not be relevant.
Overall, it's a great product and an excellent addition to Tesla’s product suite, but it's not the game changer the cars and soon to be trucks are though in my opinion.
This question originally appeared on Quora - the place to gain and share knowledge, empowering people to learn from others and better understand the world. You can follow Quora on Twitter, Facebook, and Google+. More questions:
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Source Forbes
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