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Cake day: June 15th, 2023

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  • It’s two sided.

    Yes you waste money by not exporting the electricity-transformed version of your resource (wind, sun, chemical potential, etc.).

    But on the flip side if you export lower across your whole site, this means more losses at the inverters which can shorten operational lifetimes and lead to quickened inverter failures and needs for replacement. Those maintenance costs eat into your profit as well.

    As someone in the industry, I’d imagine that inverter-based producers really just react to the rate structures of whatever grid and utility they hook up to. If the incentives of that utility favor one mode of operation during supply-demand mismatches - such as complete site curtailment - then that is what generators will do. If the incentives favor partial generation where only certain blocks of your solar or wind or BESS plant are switched off while others remain on, then we could see more producers do that.

    Ultimately though you need to have a way to operate your site in those conditions to help balance out operation and nonoperation. If whenever a curtailment signal comes to your site, and in response you always shut off Block B while leaving Block A on, then Block A will experience accelerated lifetime degradation over Block B. Inverters, transformers, cables, panels will fail faster in Block A than Block B. But if you could rotate your curtailment/demand response such that certain blocks/strings are used sequentially and that lifetimes are averaged out, this might solve the problem. Think about how farmers rotate which crops they plant in which of their fields to avoid famine and soil degradation.

    I think demand response is taking off in the utilization markets like in buildings and industrial settings, but really I think the principles we’ve learned from that should be carried over to generation markets as well. It’s only a matter of time as the industry matures and smart technology penetrates the grid and generation markets.


  • You can do more with them too actually. You can ramp down the AC power production incrementally to meet curtailment requirements, in theory. When you do that though you subject your inverters to greater strain/losses and less efficiency which shortens your lifetime.

    If inverter-based producers in solar, wind, and/or BESS want their sites to last for 30-40 years so that ROI is achieved via operation, then it is in their interest to protect their equipment and operate as much as possible at rated conditions or de-energized conditions.

    You might think that it would make sense to have more of a slider control between ON and OFF to save everyone, from producers to grids to consumers, but my guess from being in the industry is that grids don’t really supply incentives for that kind of operation. If they did, maybe you’d see more variable control at utility- and community-scale levels.


  • I’m in solar/BESS, and I mean more and more DER sites are making use of string inverters which break out arrays into greater chunks than with central inverters. With those, you have more granularity of control where you can drop entire blocks/strings at a time to fall to your curtailed export rate.

    You might ask yourself though why DERs can’t just ramp inverter outputs up or down to match curtailment automatically across a whole site. You can absolutely do that, but what happens is your solar or wind resource stays high on the DC or low frequency (LF) AC side, respectively, while power frequency AC is low on the other side of the inverters. This is referred to as DC:AC ratio in the biz, and the higher that ratio, the more losses your inverters experience and less efficient they are. This also puts a huge strain on your inverters and can lessen their operational lifetime.

    But really, DERs tie into the grid at distribution level and so they don’t fall under the regulations of FERC & NERC (at least in North America). This means that smaller producers don’t have the same requirements for control as do utility-scale players, so the incentive to control these string inverters at that granular level isn’t there. It’s much easier to just trip the main breaker and wait until the utility gives you the go ahead to turn back on.

    I suspect that at lot of producers may want to look into greater control capabilities in the future, but this also depends on inverter OEMs too allowing that control.


  • One solution to what you’re describing is to expand the grid. If your grid stretches half the planet, when the East starts to experience night, the West still experiences day and can ship electricity from renewables to the East to make up for their self curtailment. The same goes for wind where if one location on the planet doesn’t experience wind, odds are another location does and the power can be shuffled around.

    Another option is to build out more battery storage such that any clipped energy from solar or wind - that is, the energy that can be generated from your solar or wind resource but that can’t be exported because it would overload your inverters or transformers or exceed your PPA agreement with your utility - is stored and can be exported for 2-4 hours as the sun goes down or wind dies out.

    Not a lot of renewables sites are colocated with battery storage, but more and more are.


  • The original commenter’s (OC’s) point has nothing to do with renewables’ reliability.

    It is entirely to do with generation vs demand. Grid operators could ask other generators like coal, nuclear, hydro, etc. plants to curtail so inverter-based renewables can export power, but that’s not likely because those producers can’t ramp generation up and down as easily.

    Grid stability is a problem when you have overcrowding of generation without enough demand on given feeders. This is moreso an issue with the utilities anyways and how they plan their transmission and substation upgrades.





  • I guess it comes down to whether we want to primarily communicate battery size in terms of charge (Coulombs = Amps * Time) or energy (Joules = Watts * Time).

    The first metric you multiply by your operating voltage to get the second metric, whereas the second metric you have to divide by your voltage to get the first. Depends on what comes easier to most people.








  • There are other ways in which we sell our bodies in exchange for resources. A lot of people point to soldiers, but for those of us in knowledge work, we sell our brains in exchange for stress and depression if things aren’t in balance. Think about construction workers who break their wrists drilling down floorboards, or caregivers that expose their immune systems to a high quantity of kids who are likely to spread any bugs they pick up because they don’t know better.

    Sex work just involves people selling entertainment or enjoyment in a more intimate setting. The fact that it is intimate doesn’t change that it’s work, and that resources can be exchanged for service.

    I think this all comes down to stereotypes specific to a certain culture. Hoping I see my culture in America make it more legal so we don’t have some of the issues that come from this market not being legal


  • Hey nice to have ya!

    Friendly reminder that the Fediverse is awesome, and you have the power to control the content in your feed not only by which subs you subscribe to or instances you make an account on, but also which you can block - including specific users if it comes to that. Of course, instance admins can do the same, and if that happens to content you want to see, you can always make a new account on a different instance and see everything.

    It takes a little to understand the Fediverse structure, but imo it’s one of the best ways social media can be structured.