[HN Gopher] Modeling light for solar panel placement in urban se...
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       Modeling light for solar panel placement in urban settings
        
       Author : codereviewed
       Score  : 26 points
       Date   : 2022-08-11 14:31 UTC (8 hours ago)
        
 (HTM) web link (engineering.cmu.edu)
 (TXT) w3m dump (engineering.cmu.edu)
        
       | causi wrote:
       | I'm surprised there's not a cheap internet of things solar energy
       | measurement pod you can buy a passle of and put all over your
       | property to log daily sun exposure.
        
         | jpm_sd wrote:
         | Seems like a very doable design problem. The angle of incidence
         | of the sun varies quite a bit with the time of year, however,
         | so if you can model accurately that's going to be a more
         | effective use of your time.
        
           | causi wrote:
           | Google Maps has rough tree and structure geometry data for a
           | huge portion of the globe. I wonder if you could scrape that
           | and use it to calculate maximum sun exposure.
        
             | ZeroGravitas wrote:
             | https://sunroof.withgoogle.com/
        
       | Dave_Rosenthal wrote:
       | Honest question, is there any good reason for doing solar on
       | buildings in urban areas? It seems like solar power it should be
       | considerably less expensive from large installations on cheaper
       | land outside the city. The only reasons I can think of to built
       | it on buildings are:
       | 
       | 1) Virtue signaling. (Not a good reason) 2) The person who builds
       | it truly wants solar but doesn't own that other land so it's
       | simple to just use their roof. (Not a good reason) 3) Power
       | transmission from another location more than offsets the cost
       | savings. (I doubt this is true) 4) Tax/policy distortions. (Not a
       | good reason)
       | 
       | Am I missing something? Is there a good reason for rooftop solar?
        
         | MrGLaDOS wrote:
         | Solar PV takes up a lot of land. Rich, densely populated
         | countries (like the Netherlands) find the areas outside of the
         | cities to be more valuable as (recreational) nature, for
         | upcoming housing projects, or for agricultural use.
         | 
         | Another (short term) practical reason is that remote areas
         | where the land is cheap usually have a weaker connection to the
         | electrical grid. As erecting vast solar parks takes months
         | while fortifying the grid takes years (and is very expensive),
         | this creates bottlenecks. Erecting new solar parks in such
         | remote areas is therefore (temporarily) prohibited:
         | https://www.sunforson.com/dutch-provinces-of-friesland-and-g...
        
         | marcosdumay wrote:
         | You are already going to build a roof. Putting solar panels on
         | it has very little marginal costs.
         | 
         | It's certainly cheaper than buying some land exclusively for
         | it, building supporting infrastructure, and then transmitting
         | the power to the place you live.
         | 
         | Retrofitting a roof with solar panels is a different situation,
         | but I won't be surprised if the costs of dealing with all of
         | the power generation, transmission and distribution companies
         | add up to more than just putting some panels there.
        
         | jjoonathan wrote:
         | Why did you bury #3?
         | 
         | Transmission and distribution aren't trivial. Under the right
         | circumstances, people can get very attractive ROI periods, not
         | to mention a degree of independence.
         | 
         | I can't be the only one who learned from the Texas incident
         | that our grids our metastable and one bad crash away from a
         | multi-week outage. I can't be the only one who thought "F that,
         | I want a plan B."
        
           | s1artibartfast wrote:
           | Transmission requirements don't go away with rooftop solar.
           | In fact, they become a huge sticking point.
           | 
           | If customers need transmission at night, or even once a year,
           | they still need all the infrastructure in place.
        
             | ghostbrainalpha wrote:
             | Having a plan B, doesn't mean you completely abandon plan
             | A.
             | 
             | Would decide against having a spare tire on your car, just
             | because your traditional 4 tires were still required?
        
         | s1artibartfast wrote:
         | Yes, there is a very good reason.
         | 
         | It is an action that can be done by an individual that doesn't
         | require coordination with tens of millions of other people.
         | 
         | This is a real value that should not be underestimated.
         | 
         | With respect to you other points, yes, economies of scale and
         | more ideal sites provide vast advantages commercial solar.
         | Commercial solar farms are ~$1/watt and residential is
         | $2-3/watt with subsidies.
        
           | kkfx wrote:
           | Keep attention to an aspect: most setups are grid-connected
           | because full autonomy is not possible or simply way too
           | expensive. As a result while a single human can decide
           | (depending on local laws on that topic) putting some panels
           | and relevant inverters the grid need to cope with far less
           | stable and predictable loads grid.
           | 
           | Keeping a grid up and running is a delicate balance between
           | varying consumption and production, like having a tight rope
           | with various needles suspended by the their eye, some with
           | added weight, some with a hand to push the rope 50/60Hz. We
           | normally "average the load" of a grid making large enough but
           | not too large grids with few big generators and many small
           | (or few large but constant) loads. With renewables and a
           | gazillion of grid-tied inverters who tend to be (far) quicker
           | than big ones the frequency keep a bit schizophrenic:
           | inverters see constantly a bit too high or too low frequency
           | and keep adjusting their output generated instability. If
           | they are few others local consumers around them just absorb
           | their output, but if they are MANY keeping the grid up is a
           | nightmare.
        
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       (page generated 2022-08-11 23:02 UTC)