Hacker News
points by _heimdall 13 hours ago | 0 comments
The biggest challenge is keeping the energy almost perfectly in phase. US power runs at 60Hz and most grid equipment fails quickly if that changes even a little bit.

If I'm not mistaken, that was what hit Spain when much of their grid went down for hours. The analysis I heard was that they were running entirely on renewables and it fell out of phase causing large scale safety shutdowns.

[–] ttul 13 hours ago
Fortunately, interconnects cannot go out of phase easily. If one region is out of phase with another, massive currents flow down the transmission lines within milliseconds, causing generators at one side or the other to slow down or speed up. I have seen this effect live at a hydroelectric dam. We were watching the turbine shaft spin at the moment they switched on some giant interconnect. There was a phase-alignment dial and it just instantly pinged up to 0 while the spinning shaft shuddered, slightly altering its rate of rotation in the blink of an eye.
[–] _heimdall 8 hours ago
Is that same functionality available in solar or wind type scenarios?

When I heard the Spain issue being described by a grid engineer, they were focusing on the lack of rotational mass in those systems compared to the large turbines used in other generator designs as the reason solar could go out of phase more easily. What you're describing sounds like that scenario, hydro has large enough rotational mass to keep things stable.

[–] qlte 13 hours ago
That's the usual failure mode of any grid, aggressive load shedding will be used as a last resort to keep the frequency within tolerances.

The renewable aspect is because historically they were installed with "grid following" inverter systems instead of "grid forming" which can maintain frequency even if temporarily islanded in a partition without spinning mass generators to set frequency.

There's nothing intractable about a 100% renewable grid, the technology exists and has already been deployed in new installations.

[–] _heimdall 9 hours ago
Oh yeah for sure, I had assumed it was likely a transitionary issue with new systems not functioning well with older systems and different assumptions.
[–] ViewTrick1002 8 hours ago
No this is misinformation that continues to be spread.

The Iberian blackout was caused by a lack of reactive power leading to voltages going out of their designed ranges.

The Iberian grid had adequate inertia at the time.

Reasonable grids have forced inverter based generation to manage reactive power for over a decade. But Spain due to lackluster processes relied on thermal plants to provide it. And they didn’t provide the expected amount.

There were some more confounders around oscillations and what not but the central cause came down to voltage control. Which is near trivial to solve in 2026. If you just force everyone to do it.

[–] _heimdall 3 hours ago
I'll look into this further. I heard about this from a podcast episode on The Great Simplification, I'd be very surprised if it turned out to be misinformation though its always possible. Nate is pretty damn thorough in his research and sits squarely on the left half of the political spectrum, I'd usually expect misinformation like this to come from the (US) right.