Comment by reactordev
13 hours ago
This isn’t remotely true. Solar / wind / nuclear / coal / gas / any electrical source including from neighboring grids can be inbound or outbound from your grid using, the grid. There are capacitors and transformers, relays and transmission lines. Any energy source can provide power. Solar used to give money back to its owners by selling power back to the grid but they killed that initiative quickly and will just use your energy you provide.
The issues you describe are from coal, oil, and gas lobbyists saying solar isn’t viable because of nighttime. When the grid is made up of batteries…
If every house had solar and some LiFePo batteries on site, high demand can be pulled from the grid while during low demand and high production, it can be given to the grid. The energy companies can store it, hydropower or batteries, for later. We have the ability. The political will is simply the lobbyists giving people money so they won’t. But we can just do it anyway. Start with your own home.
> Any energy source can provide power.
Not all prime movers are the same with regard to grid dynamics and their impact.
Solar, wind, etc., almost universally rely on some form of inverter. This implies the need for solid state synthetic inertia to provide frequency response service to the grid.
Nuclear, coal, gas, hydropower, geothermal, etc., rely on synchronous machines to talk to the grid. The frequency response capability is built in and physically ideal.
Both can work, but one is more complicated. There are also factors like fault current handling that HN might think is trivial or to be glossed over, but without the ability to eat 10x+ rated load for a brief duration, faults on the grid cannot be addressed and the entire system would collapse into pointlessness. A tree crashing into a power line should result in the power line and tree being fully vaporized if nothing upstream were present to stop the flow of current. A gigantic mass of spinning metal in a turbine hall can eat this up like it's nothing. Semiconductors on a PCB in someone's shed are a different story.
Large solar sites are required to be able to provide reactive power as well as maintain a power factor of 0.95 to avoid all of the issues you mentioned.
Reddit post by an EE explaining it better than I can: https://www.reddit.com/r/AskEngineers/comments/qhear9/commen...
> There are also factors like fault current handling that HN might think is trivial or to be glossed over, but without the ability to eat 10x+ rated load for a brief duration, faults on the grid cannot be addressed and the entire system would collapse into pointlessness.
I don’t understand what you are talking about here. I don’t work in the utility world, I sell and run commercial electrical work, but handling available fault current in my world is as simple as calculating it and providing overcurrent protection with a high enough AIC rating or current limiting fuses. I don’t see why the utility side would be any different.
The utility side has found that vaporising short circuits is a useful feature, as that includes e.g. twigs hitting a power line.
There are breakers, of course, but they react slowly enough that there will absolutely be a massive overdraw first. Then the breaker will open. Then, some small number of seconds later, it will automatically close.
It will attempt this two to four times before locking out, in case it just needs multiple bursts. It’s called “burning clear”, and it looks just as scary as you’d think… but it does work.
So, solar suppliers need to also survive this.
Reactive power handling concerns are in addition to the issues I described. Not equivalent to them.
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Yeah, DC vs AC power. 12v vs 120v or 240v. This isn’t a limitation. All energy sources must be converted to useable energy to the grid somehow. So every power source requires an inverter or a down stepper or a really advanced rectifier or all of the above.
The people you're replying to aren't talking about converting from AC to DC or stepping voltage up or down. Rather, they're talking about grid stability. You can have mechanisms to convert from AC to DC and to step voltage up or down, but still have a unstable grid. We had a notable example of that last year: https://en.wikipedia.org/wiki/2025_Iberian_Peninsula_blackou....
One way to think about this problem is that our electrical grids are giant machines—in many ways, the largest machines that humanity has every constructed. The enormous machine of the grid is comprised of many smaller connected machines, and many of those have spinning loads with enormous mechanical inertia. Some of those spinning machines are generators (prime movers), and some are loads (like large electric motors at industrial facilities). All of those real, physical machines—in addition to other non-inertia generators and loads—are coupled together through the grid.
In the giant machine of the grid, electricity supply and demand have to be almost perfectly in sync, microsecond to microsecond. If they're not, the frequency of the grid changes. Abrupt changes in frequency translate into not only electrical/electronic problems for devices that assume 60 Hz (or 50, depending on where you are), but into physical problems for the machines connected to the grid. If the grid frequency suddenly drops (due to a sudden drop in generation capacity or sudden drop in load), the spinning masses connected to the grid will suddenly be under enormous mechanical stress that can destroy them.
It's obviously not possible to instantaneously increase or decrease explicit generation in response to spikes or drops in load (or alternatively, instantaneously increase or decrease load in response to spikes or drops in generation). But we don't need to: all of the spinning mass connected to the grid acts as a metaphorical (and literal) flywheel that serves as a buffer to smooth out spikes.
As the generation mix on the grid moves away from things with physical inertia (huge spinning turbines) and toward non-inertial sources (like solar), we need to use other mechanisms to ensure that the grid can smoothly absorb spikes. One way to do that is via spinning reserves (e.g. https://www.sysotechnologies.com/spinning-reserves/). Another way to do it is via sophisticated power electronics that mimic inertia (such as grid-forming inverters, which contrast with the much more common grid-following inverters).
To learn more about this topic, look up ancillary services (e.g. https://en.wikipedia.org/wiki/Ancillary_services). This Shift Key podcast episode is also a great introduction: https://podcasts.apple.com/us/podcast/spains-blackout-and-th...
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Or just grid forming inverters?
https://spectrum.ieee.org/electric-inverter-2667719615
These do not address the concern of fault current handling. This is a much more localized and severe condition than frequency deviation. Think about dropping a literal crowbar across the output of a solar inverter. This is a situation the grid has to deal with constantly.
I'd argue that nothing that uses semiconductors would be suitable for the task. They get you to maybe 2x rated current capacity for a meaningful duration. A spinning turbine can easily handle 10x or more for a much longer duration.
We could put so many redundant transistors in parallel that we have equivalent fault handling, but then we are into some strong economic issues. There's also no room for error with semiconductors. Once you start to disintegrate, it's all over ~instantly. There is no way to control this. A synchronous machine can trade downstream maintenance schedule for more current right now. The failure is much more gradual over time. A human operator can respond quickly enough if the machine is big enough.
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Also, power companies did not necessarily kill energy export incentives. Here in Massachusetts my meter “runs backward” when I export to the grid. This does not earn me money but it does earn me kWh credits, which means that if I am net negative for energy import in the summer and net positive for import in the winter, I can be net zero (or close to it) for the year.
In MA and a few other states, polluters are also required to buy “renewable energy credits.” Since I have a solar array I can sell my RECs whether I export energy or not. It’s my first year with a solar array, so I’m not sure how much to expect, but neighbors tell me that they earn between $500-$1000 a year.
In a future with solar and batteries, daytime and nighttime electricity pricing cannot be equal - else nobody would bother to have a battery (grid scale or at home).
Rules and regulations could solve that problem (meter not allowed to go backwards, solar companies are forced to pay some kind of battery credit, etc), but the free market will always outcompete.
Therefore, I forsee the future lies in 'smart' electricity meters which can charge different rates at different times of day - perhaps with minute by minute live pricing.
We already do this. Charging different rates for different times of day.
It’s called TOU pricing.
Here in Ireland, night-time power prices are much lower than daytime.
I’m happy enough that a battery will serve me equally well in both modes, but there’s definitely going to be a period where all it does is support self-consumption.
And then a storm hits texas and without realizing it you run up a $30,000 electricity bill in a single night of not freezing.
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It's hard for people to really understand this because utilities and grid operators are using this is a headline justification for electric capital projects. In New York, they've deferred capital projects for decades and we're absorbing a massive distribution charge increase. I think my electric delivery portion of the bill is up 40%.
Well there are real challenges here. Generators which rely on massive spinning things naturally provide the grid with inertia; they resist changes to grid frequency. Power sources which rely on inverters or otherwise dynamically adapt to grid frequency don't naturally provide the same inertia.
This is a solvable problem, but it requires a solution nonetheless.
Very good point!!!
The frequency (50hz or 60hz) comes from those rotational forces from the generators and until we can eliminate them, we have to play nice with them.
Luckily, we have GFMI’s. Grid-forming inverters that can emulate 60hz push pull but you’re right that it’s more than just voltage since we are dealing with high voltage alternating current.
That too can be replicated. There are a few centrifuges out there. Not batteries, but spinning masses meant to keep the frequency stable. Some are looking at using air conditioning motors, of which we have millions, as such a spinning mass.
Grid frequency can also be regulated with batteries and grid forming inverters.
https://www.energy-storage.news/batteries-are-number-one-at-...
https://arena.gov.au/blog/australias-grid-forming-battery-re...
Yeah, as I said it's a solvable problem. It just needs solutions to be implemented