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>If one's aim is progressing along the Kardashev scale I doubt most folks who put solar panels on their roof are doing it to advance a hundred thousand year gr

>If one's aim is progressing along the Kardashev scale I doubt most folks who put solar panels on their roof are doing it to advance a hundred thousand year grand strategy for galactic scale energy consumption. I think it's mostly stuff like minimizing carbon footprint and saving money over the 20 year lifetime of a project.

JumpCrisscross 8y ago
> saving money over the 20 year lifetime of a project Practical point being, a future where everyone has rooftop solar is a future where everyone is spending more on energy than the alternate future of utility-scale solar. If we want to save money, the cheapest solution, i.e. utility-scale solar, is the way to go.
- epistasis 8y ago
  Different entities have different costs. Depending on the installation, maintenance, and component costs of different parts of a system, it may end up making a lot of sense to massively downsize the grid and make most single family homes into islands. Electrical grids are hugely expensive, and even if the raw cost of utility scale solar installs is lower than residential, the delivery is killer.
- TheSpiceIsLife 8y ago
  While I understand what you're getting at here, I see little evidence to suggest utility controlled generation will ever be cheaper. People are installing roof-top solar now because they're able to seeing savings in the form of reduced electricity bills now. Practical point being, if you tell people: "don't install roof-top solar now, keep paying outrageous electricity prices (I'm in Australia, see) and hope that one day the electricity retailers pass on the savings when they can buy wholesale solar / wind for next to nothing" you can expect to be laughed at.
  - thinkcontext 8y ago
    Utility scale solar is definitely cheaper. NREL puts residential at $2.80/watt vs $1.03 for utility scale[0]. Its only cheaper for consumers because of subsidies and net metering. [0] https://www.nrel.gov/news/press/2017/nrel-report-utility-scale-solar-pv-system-cost-fell-last-year.html https://www.nrel.gov/news/press/2017/nrel-report-utility-sca... edit: Missed the part where you are in Australia, I was giving numbers for the US. I believe its true the residential numbers are cheaper in Australia due to lower soft costs, its still true that utility scale has a cost advantage because of labor cost savings.
  - apendleton 8y ago
    Can't speak for Australia, but at least in the US, a big part of the reason rooftop solar ends up looking like such a savings is net electric metering, where power companies buy surplus power from solar panel owners at the same rates that they sell those users power at night. The tricky thing is that the price users pay for power doesn't just include generation costs, but also transit, grid maintenance, etc., which rooftop solar owners benefit from even though they no longer pay for it -- these costs end up being borne by other rate-payers, who effectively cross-subsidize rooftop owners' freeloading. In the early days of solar, there was a good public policy argument to be made here: solar power is a net societal good (air quality, carbon footprint, creation of solar economies of scale that drive prices down for everyone, etc.), and power companies weren't going to do solar on their own. Now, though (again, at least in the US), utilities are making massive investments in grid solar, and it's dramatically cheaper than rooftop solar. Like: a quarter the cost per kilowatt hour of generation capacity. So now I think it's sensible to ask: if we're going to ask ratepayers to subsidize solar generation, does it really make sense for us to spend their subsidy on a way of doing solar that's objectively much more expensive just because it saves a few specific users money? They could be getting 4x the bang for their buck if we spent that subsidy on grid-scale instead, and then the economics of rooftop solar mostly go to shit (as well they probably should -- it's needlessly expensive).
    - Brakenshire 8y ago
      In Australia solar is cheaper than the grid even taking account of battery storage.
- mikeash 8y ago
  Is it really cheaper? There are some economies of scale, but how much? Rooftop solar has zero land cost and low transmission costs.
  - thinkcontext 8y ago
    Yes, over twice as cheap. According to NREL, residential is $2.80/watt vs $1.03/watt for utility scale. https://www.nrel.gov/news/press/2017/nrel-report-utility-scale-solar-pv-system-cost-fell-last-year.html https://www.nrel.gov/news/press/2017/nrel-report-utility-sca...
    - mikeash 8y ago
      That doesn’t seem to account for the two factors I mentioned, although I certainly wouldn’t expect them to make up that difference.
      - 18pfsmt 8y ago
        I haven't read the NREL report, but my father was involved with them for 10 years as an investor. For utility scale, they can use thin-film panels which are more efficient, but more costly upfront (FirstSolar is the big player).
- toomuchtodo 8y ago
  You’re optimizing for the wrong outcome. Cost is only one factor. There’s also being immune from utility rate increases, on-site perpetual backup power generation, and reduction of transmission and distribution costs. Disclaimer: I have rooftop solar.

JumpCrisscross 8y ago

> saving money over the 20 year lifetime of a project Practical point being, a future where everyone has rooftop solar is a future where everyone is spending more on energy than the alternate future of utility-scale solar. If we want to save money, the cheapest solution, i.e. utility-scale solar, is the way to go.

epistasis 8y ago
Different entities have different costs. Depending on the installation, maintenance, and component costs of different parts of a system, it may end up making a lot of sense to massively downsize the grid and make most single family homes into islands. Electrical grids are hugely expensive, and even if the raw cost of utility scale solar installs is lower than residential, the delivery is killer.
TheSpiceIsLife 8y ago
While I understand what you're getting at here, I see little evidence to suggest utility controlled generation will ever be cheaper. People are installing roof-top solar now because they're able to seeing savings in the form of reduced electricity bills now. Practical point being, if you tell people: "don't install roof-top solar now, keep paying outrageous electricity prices (I'm in Australia, see) and hope that one day the electricity retailers pass on the savings when they can buy wholesale solar / wind for next to nothing" you can expect to be laughed at.
- thinkcontext 8y ago
  Utility scale solar is definitely cheaper. NREL puts residential at $2.80/watt vs $1.03 for utility scale[0]. Its only cheaper for consumers because of subsidies and net metering. [0] https://www.nrel.gov/news/press/2017/nrel-report-utility-scale-solar-pv-system-cost-fell-last-year.html https://www.nrel.gov/news/press/2017/nrel-report-utility-sca... edit: Missed the part where you are in Australia, I was giving numbers for the US. I believe its true the residential numbers are cheaper in Australia due to lower soft costs, its still true that utility scale has a cost advantage because of labor cost savings.
- apendleton 8y ago
  Can't speak for Australia, but at least in the US, a big part of the reason rooftop solar ends up looking like such a savings is net electric metering, where power companies buy surplus power from solar panel owners at the same rates that they sell those users power at night. The tricky thing is that the price users pay for power doesn't just include generation costs, but also transit, grid maintenance, etc., which rooftop solar owners benefit from even though they no longer pay for it -- these costs end up being borne by other rate-payers, who effectively cross-subsidize rooftop owners' freeloading. In the early days of solar, there was a good public policy argument to be made here: solar power is a net societal good (air quality, carbon footprint, creation of solar economies of scale that drive prices down for everyone, etc.), and power companies weren't going to do solar on their own. Now, though (again, at least in the US), utilities are making massive investments in grid solar, and it's dramatically cheaper than rooftop solar. Like: a quarter the cost per kilowatt hour of generation capacity. So now I think it's sensible to ask: if we're going to ask ratepayers to subsidize solar generation, does it really make sense for us to spend their subsidy on a way of doing solar that's objectively much more expensive just because it saves a few specific users money? They could be getting 4x the bang for their buck if we spent that subsidy on grid-scale instead, and then the economics of rooftop solar mostly go to shit (as well they probably should -- it's needlessly expensive).
  - Brakenshire 8y ago
    In Australia solar is cheaper than the grid even taking account of battery storage.
mikeash 8y ago
Is it really cheaper? There are some economies of scale, but how much? Rooftop solar has zero land cost and low transmission costs.
- thinkcontext 8y ago
  Yes, over twice as cheap. According to NREL, residential is $2.80/watt vs $1.03/watt for utility scale. https://www.nrel.gov/news/press/2017/nrel-report-utility-scale-solar-pv-system-cost-fell-last-year.html https://www.nrel.gov/news/press/2017/nrel-report-utility-sca...
  - mikeash 8y ago
    That doesn’t seem to account for the two factors I mentioned, although I certainly wouldn’t expect them to make up that difference.
    - 18pfsmt 8y ago
      I haven't read the NREL report, but my father was involved with them for 10 years as an investor. For utility scale, they can use thin-film panels which are more efficient, but more costly upfront (FirstSolar is the big player).
toomuchtodo 8y ago
You’re optimizing for the wrong outcome. Cost is only one factor. There’s also being immune from utility rate increases, on-site perpetual backup power generation, and reduction of transmission and distribution costs. Disclaimer: I have rooftop solar.