12 comments

  • ltrg5 hours ago
    Really cool stuff. Nitpick: it failed to grab an OSM ID for my house and fell back to postcode centroid, but then still reported LIDAR-derived shading at quite high precision.<p>I&#x27;m wondering if it should fall back to a more general shading approach when no OSM building footprint is available, to avoid false precision? My street has a gap in the houses on the other side from mine, so picking the right location matters for the calculation.<p>You could also try Inspire Index polygons instead of OSM? These correspond to actual lease&#x2F;freehold boundaries.
    • ruaraidh5 hours ago
      Thanks - I didn&#x27;t know about Inspire Index, I&#x27;ll check it out. I tend to agree about false precision. My first instinct was to use the synthetic horizon for addresses in that group, but I think that&#x27;s over positive. A range might be better (if a bit more complex)?
  • ifh-hn3 hours ago
    &gt; Worth it. The kit pays for itself in 7.1 years; over 20 years it&#x27;s good for about £1,095 net.<p>This is my issue with this sort of thing. Am I going to have this kit in 7 years? Or would I upgrade to better stuff at the technology improves?
    • brk1 hour ago
      These calculations often fail to account for present vs future value of money.<p>If you’re financing the system you have no big cash outlay, but returns are further out, possibly never when accounting for the useful like of the system.<p>With cash up front all the returns are yours, but they are much lower than what that cash would net you in an average investment.<p>The financial math on small solar systems can be complex. If the system is sufficient to provide power to major appliances in a power outage (assuming you have a power outage risk in your area), it can make more sense to tie money up in these systems.
    • pjc502 hours ago
      Why would you replace it if doing so is uneconomic?<p>Panel lifetime is very high. The scope for efficiency improvement is not huge (unless there is a cost breakthrough in multi band photon capture). It&#x27;s not a car, phone, or computer. It&#x27;s more like the rest of the house electric infrastructure.<p>I had my rooftop solar over 10 years ago and basically intend to leave it until some maintenance issue forces action.<p>(Also, the kit secondhand value is hard to determine but far from zero; 30-50% maybe?)
    • IshKebab2 hours ago
      The technology is unlikely to improve meaningfully in 7 years. And you&#x27;d only upgrade if it was a financial improvement so it makes complete sense to give an estimate based on keeping it for 20 years.<p>I don&#x27;t see what your issue is.
    • toomuchtodo3 hours ago
      Depends on your energy requirements and future technology and energy costs. At the moment, one should value this outlay as a fixed income equivalent investment [1].<p>The panels have a ~25 year warranty though [2] (at which point, they should still produce ~80% of rated output), so it’s entirely possible to just leave them in place. At a certain age (~55-60), these are the last PV panels you’ll need to buy, as they’ll potentially outlive you (assuming developed country life expectancy).<p>[1] <a href="https:&#x2F;&#x2F;magnifina.com&#x2F;articles&#x2F;rooftop-solar-yield&#x2F;" rel="nofollow">https:&#x2F;&#x2F;magnifina.com&#x2F;articles&#x2F;rooftop-solar-yield&#x2F;</a><p>[2] <a href="https:&#x2F;&#x2F;www.energysage.com&#x2F;solar&#x2F;solar-panel-warranties&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.energysage.com&#x2F;solar&#x2F;solar-panel-warranties&#x2F;</a>
    • ErroneousBosh1 hour ago
      I got the exact same values.<p>I&#x27;d like it if it would actually show me how much sun it thinks I&#x27;d get at the postcode I put in. I&#x27;ve got about a third of an acre of garden in a 6 acre field to play with, before I start having to dig up roads. I can afford to be quite free and easy with placement ;-)
  • redfloatplane6 hours ago
    Huh, TIL about the National LIDAR Programme: <a href="https:&#x2F;&#x2F;www.data.gov.uk&#x2F;dataset&#x2F;f0db0249-f17b-4036-9e65-309148c97ce4&#x2F;national-lidar-programme" rel="nofollow">https:&#x2F;&#x2F;www.data.gov.uk&#x2F;dataset&#x2F;f0db0249-f17b-4036-9e65-3091...</a><p>Very interesting stuff and quite a large undertaking! I&#x27;m often impressed by the quality of the UK&#x27;s open data.
    • cowsandmilk56 minutes ago
      &gt; I&#x27;m often impressed by the quality of the UK&#x27;s open data.<p>The ordnance survey not being open data is a bad look though.
    • kilroy1235 hours ago
      I noticed this as well! Very interesting.
  • pinkgolem27 minutes ago
    I am just surprised about the cost?<p>Kits in Germany are 300€ without a battery.
    • gib44419 minutes ago
      Surprised which way? Too cheap? Too expensive? Surprised things differ in price by country?
  • overfits_ai49 minutes ago
    This is a really interesting project! The use of LIDAR data to account for actual building shadows is a clever approach. I&#x27;d be curious to see how this compares to commercial solar assessment tools in terms of accuracy. The UK&#x27;s move to legalize plug-in solar is great for residential adoption.
  • GordonS6 hours ago
    This is really nice! Would be great if it could handle regular rooftop solar calculations too.
    • ruaraidh6 hours ago
      Thanks! Should be doable, I just got excited by the new shiny thing first.
  • realty_geek4 hours ago
    Nice. I&#x27;m working on a project called homestocompare to help people house-hunting in the UK.<p>Would be nice to add this as an extra data point when comparing. Are you open to collaborating at all?
    • ruaraidh4 hours ago
      Absolutely! I have some other datasets that might be useful too (e.g. air quality). Drop me a line: ruaraidh[at]southlondonscientific.com :)
      • realty_geek1 hour ago
        Great, thanks - I&#x27;ll drop you a line.
    • simonjgreen3 hours ago
      Let me know if you’d like access to alt net availability data
      • realty_geek1 hour ago
        Sorry, not sure what you mean by &quot;alt net availability&quot;
  • dnlzro2 hours ago
    This is a great use of open data!<p>Please consider making the source code available. I’d love to make something similar for your friends across the pond (in Canada).
  • domh3 hours ago
    Would be good to be able to select multiple points on the compass and have it tell me the best place for it (front and back garden)
    • ruaraidh3 hours ago
      Good idea. I want to add specific options for different mounting locations (sheds etc) as well.
  • ErroneousBosh59 minutes ago
    &quot;Any address in Britain&quot;<p>&quot;Caveats: - Outside LIDAR coverage (most of Scotland and Wales) it falls back to a synthetic horizon (less accurate)&quot;<p>So, &quot;any address in the most of the southern half of Britain&quot;?
  • IshKebab2 hours ago
    What if I already have solar, can I add this?<p>Also do you actually need a balcony or can you hang these out of a window somehow? Very few houses in the UK have balconies.
    • jimnotgym1 hour ago
      You can put it on the ground if you like
  • toomuchtodo3 hours ago
    Great work. Is it possible to use this dataset to calculate total plug in solar potential within the geographic constraint?
    • ruaraidh2 hours ago
      Oh, that&#x27;s such a good idea! I suppose the challenge is knowing where there are installable surfaces are (or at least making defensible guesses). I&#x27;m going to have a go at this...