Comment by epistasis

Comment by epistasis 12 hours ago

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Check out your grid bill and you'll probably see that cost of the grid is higher than the cost of the generation.

Local solar requires far less grid, and expanding the grid is one of the greatest (political, not technical) challenges of this era in the US.

Unless you're accounting for the grid costs, the "cost" of utility vs. rooftop is not an apples-to-apples comparison.

As far as a "con" the only con is that the costs in the US for rooftop solar are multiples higher of other places, like Australia. That's the con. Australia also shows that rooftop solar is great for grid in general, greatly driving down costs.

Of course, rooftop solar is terrible for utilities, so you are going to encounter tons of astroturf denouncing it all over the web, and even face to face. Utilities are fundamentally threatened by consumres taking over more and more of their own electricity responsibility, especially as batteries get super cheap.

EnPissant 10 hours ago

The problem is when there are long stretches of little to no power generation. Fully covering those gaps with batteries would require very large (and costly) storage. During this time the grid needs to be large enough to support everyone, just the same as if solar did not exist. You can say it's terrible for utilities, but at the end of the day they will have to pass the cost of maintaining the grid along to non-solar customers.

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  • epistasis 10 hours ago

    What do you mean by long stretches? Are you talking about sundown to sunset?

    In many (most?) areas, wind picks up at night, wind can't really be "local", and demand is lower at night time so that's a great use for the grid.

    Also, batteries are getting so cheap that people are putting multiple days' worth of storage on wheels, driving them around, and parking them at home during the evening peak and overnight.

    When they are that cheap, adding 10-20 kWh of local storage is going to pay for itself in no time.

    When my neighbor is overproducing solar during the day, that means that he's sending his power over to my house, which doesn't have solar. Which means that my neighborhood is pulling down less peak power. And the grid is sized for peak power, not for minimal power, so whenever that peak is lowered, it saves me money but costs the utility profits.

    Because the utility gets to recoup a fixed profit rate off of any amount of grid they are allowed by the PUC to install, whether it was needed or not. My neighbor, with the solar, also pays lots of fees for the privilege of sending me power and requiring less grid.

    This effect of shaving the peak is so extreme that solar causes the California duck curve. Though the storage that's been added in just the past two years has pretty much solved any problems needed for the evening ramp as the sun goes down, now.

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    • EnPissant 9 hours ago

      It's only the highest peak that matters. During periods of Dunkelflaute[1], batteries will run dry and the grid will need to support everyone.

      [1] https://en.wikipedia.org/wiki/Dunkelflaute

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      • epistasis 9 hours ago

        Seems like a great time and place for the iron air batteries that are getting deployed now (Form Energy). Even in the US, without Dunkelflaute, these 100:1 energy:power batteries are economical and paying for themselves on the grid. If there are several of these occasions per year it could be a great fit.

        It also seems likely that HVDC from sunnier areas like Spain or maybe even Morocco could be cheap enough. I'd recommend nuclear but EDF is having such great difficulty building it. HVDC and other exotic solutions like enhanced geothermal seem for more practical at the moment.

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  • hamdingers 8 hours ago

    > The problem is when there are long stretches of little to no power generation. Fully covering those gaps with batteries would require very large (and costly) storage.

    Perhaps local solar installations could be incentivized to include their own smaller scale storage...

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    • epistasis 6 hours ago

      California has done this with their latest version of net metering for residenial solar, NEM 3.

      It makes solar a very financially unattractive option unless there's storage attached to the system, and has drastically reduced the rate of residential solar deployment.

      NEM3 was justified under the proposition that lower-income households were "funding" the higher income households to get solar. So as solar finally gets cheap enough for the lower income households, they changed the rules again so that only those rich enough to afford batteries and solar can save money.

      NEM3 has a few nice things about it when looked at narrowly, but overall seems pretty disastrous for the state.

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      • hamdingers 6 hours ago

        Disastrous is an oversimplification you can only make if you don't understand the broader context. Grid stability is more important than some homeowners saving some money, it turns out those extra kWh being dumped onto the grid were literally costing the operator money to deal with. Those costs got passed on to _other_ consumers because of the sweetheart deal.

        Residential solar installs are way down, that's correct, residential isn't the only venue for solar, and within residential storage capacity is skyrocketing and it's already having a measurable effect on the early evening peak. Lower peaks means less capacity needs to be built just to handle a few hours. This is good.

        The unequivocally negative impact I don't have an answer for is the job losses for solar installers.

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        • epistasis 5 hours ago

          > Grid stability is more important than some homeowners saving some money, it turns out those extra kWh being dumped onto the grid were literally costing the operator money to deal with. Those costs got passed on to _other_ consumers because of the sweetheart deal.

          If that was the concern they literally did nothing to stop it. Instead of dealing with backfeeding from a distribution station, they went entirely the other direction.

          Those grid costs, if they actually existed, were in isolated areas with high levels of solar, and NEM3 will continue deployments of solar in exactly those areas.

          Solar is not "savings for some homeowners" it's literally keeping grid costs down for everyone, keeping our grid reliable on the hottest hardest to run days.

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    • EnPissant 6 hours ago

      It sounds like you are alluding to NEM3 here. If so, I'm not sure that was meant to incentivize small scale energy storage. They recently tried to implement a flat fee that would have killed residential solar entirely, even with batteries. That did not happen, but I think it shows the motivations. I'm also not sure batteries even change that much for the grid. You still need to have the capacity for lulls when all the batteries are empty.

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