• Posts
  • RSS
  • ◂◂RSS
  • Contact

  • Home Solar Resiliency

    July 20th, 2018
    preparedness, solar  [html]
    Lots of houses around here have solar panels on their roofs, due to a combination of subsidies, falling solar costs, and high electric prices. You might think this would be really good to have if something went wrong and we had an extended power outage, but standard residential solar doesn't give you any power when the grid is down.

    I'm looking at putting solar on our house, and I'm trying to figure out if it makes sense to go with something that would be more useful in an extended blackout. There seem to be more or less three options:

    • Default: no off-grid capability.

    • Secure power supply (SPS): an outlet in the basement that gives you power when the grid is down and the sun is shining.

    • Batteries: storage and the ability to switch the whole house over to run off them.

    Talking to solar people and looking online, it doesn't sound like it's possible to have an intermediate option where the whole house has power, but only when the sun is shining. I don't really understand why this can't be done with an interlock, but that's what they say.

    An SPS is only a bit more expensive [1], while a system with batteries looks like it would be about $10k. We could also do something in between, like charging a UPS or other batteries from an SPS and using it to power things when the sun was down. In general it seems like a potentially useful tool for combining with other things. Have others thought much about it?

    A big question here is how likely we would be to need something like this. Guessing, maybe over the 25 year life of the system there's a ~5% chance we have a blackout lasting more than a week and a ~2% chance that we have one lasting more than a month? I think at these odds it's worth it to get the SPS, some long extension cords, and maybe a UPS, but not worth it to get a full off-grid-capable-with-batteries system?


    [1] Most inverters don't have one, but SMA's do. Which means it's restricting inverter choice rather than directly costing more. Call it $250?

    Comment via: google plus, facebook, hacker news

    Recent posts on blogs I like:

    The Gift of It's Your Problem Now

    Recently a security hole in a certain open source Java library resulted in a worldwide emergency kerfuffle as, say, 40% of the possibly hundreds of millions of worldwide deployments of this library needed to be updated in a hurry. (The other 60% also …

    via apenwarr January 1, 2022

    The container throttling problem

    This is an excerpt from an internal document David Mackey and I co-authored in April 2019. The document is excerpted since much of the original doc was about comparing possible approaches to increasing efficency at Twitter, which is mostly information tha…

    via Posts on December 18, 2021

    Experiences in raising children in shared housing

    Sometimes I see posts about people’s hope to raise children in a group housing situation, and it often seems overly optimistic to me. In particular they seem to expect that there will be more shared childcare than I think should be expected. Today I talke…

    via The whole sky October 18, 2021

    more     (via openring)


  • Posts
  • RSS
  • ◂◂RSS
  • Contact