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The most valuable part is not the land itself, it's the grid connection. That is, the towers bringing the power to a nearby substation, the bay in the substatio
by cesarb 3y ago
The most valuable part is not the land itself, it's the grid connection. That is, the towers bringing the power to a nearby substation, the bay in the substation with the circuit breakers and measuring equipment (adding new bays to existing substations is expensive and requires expanding their size), and the budgeting for the amount of instantaneous power the solar farm can generate. Transformers in substations have a limit to how much power they can convert, and the other circuits leaving the substation (and recursively, all these things in the substations they connect to) have a limit to how much power they can carry.
Here in Brazil, we have already gotten to the point where the bottleneck to adding new grid-scale solar and wind is often not the land or the panels/turbines, but the amount of power the grid can carry, especially between the Northeast (which has lots of wind potential and plenty of solar potential) and the Southeast/South (where the power consumption is the highest). A miscalculation in this amount (the solar and wind power plants did not react as specified to a power disturbance, so the calculations were too optimistic) was a major factor in the recent country-wide blackout (https://en.wikipedia.org/wiki/2023_Brazil_blackout https://en.wikipedia.org/wiki/2023_Brazil_blackout but that article seems to be missing the later updates from https://www.ons.org.br/Paginas/Noticias/Ocorr%c3%aancia-no-SIN-em-15-de-agosto-de-2023.aspx https://www.ons.org.br/Paginas/Noticias/Ocorr%c3%aancia-no-S...).
- KennyBlanken 3y ago> The most valuable part is not the land itself ...What? > Here in Brazil Ah. When your country is destroying 8,000 square km/year in Amazon rain forest (and disappearing the indigenous people who live on it), yeah, I guess you would think land is 'cheap.' Anyway - you're missing the point. The "cost" is lost opportunity. At a certain point, between increased new panel efficiencies and the currently installed panels losing efficiency, the operator is missing out on enough power generation that they can upgrade and make more money in the long run.
- gwern 3y agoI'm not really following your point. If the land/space is not the bottleneck but the grid, then that makes the idea of leaving old panels in place all the better. As the electrical output falls by the aging panels and underutilizes your grid connection, you could just top them up with new panels, up to the limit of your grid connection (putting them in the spare land you have by stipulation). The question would seem to be, at what point is the marginal profit from the trickle of electricity from fully-depreciated old panels less than the cost of ripping them out & selling the scrap? Presumably there is such a point, as the old solar panels increasingly approach zero electrical output, if their materials aren't so worthless as to not even be worth the cost of scrapping.
- londons_explore 3y agoUnfortunately, electrical grids are very rules and procedures based. I could totally imagine that most installations aren't allowed to top up a few old solar farms with new panels without also bringing the rest of the farm up to modern standards re: fire and electrical safety. Also, I could totally imagine that grid connections are based on the manufacturers rated power output, and not the lowered output because the panels are old.
- gwern 3y agoIf grids are very conservative, that would also seem to suggest that grid operators would want existing solar farms topped up rather than replaced - old debugged solar farms declining, to be replaced by excitingly untested new ones, seems like an unnecessary risk? Compared to if one could just instead just slot in the new solar panels one by one, gradually, incrementally, into old trusty solar farms...