Solar generates more energy in US than coal for first time • Hacker News Board

Re: Solar generates more energy in US than coal for first time

#61

Post by mbgerring » Thu, Jun 11, 2026, 6:04 PM UTC

harmmonica wrote: post #22

Question for those in the know... See lots of press about balcony solar in Germany, and California recently introduced a bill to allow it (I'm guessing other states already allow it; not sure if the CA bill has a chance of becoming law). But how far are we from a more plug and play home solar system that becomes a primary energy source as opposed to a limited secondary source? And what are the issues with it actually…

It’s primarily a regulatory issue, and more states in the US will approve it over the coming years.

Re: Solar generates more energy in US than coal for first time

#62

Post by pstuart » Thu, Jun 11, 2026, 6:06 PM UTC

jillesvangurp wrote: post #33

SoftTalker wrote: post #6

Earlier quoted context omitted.

Storage is the issue. You still need to supply base load (well, all load) at night.

The whole point about modern gas/coal plants is that it's relatively cheap to shut them down and start them up again. They are backup power, not for providing inflexible base load. Batteries + renewables are taking a lot of market share and flexible backup power is much more important than baseload (inflexible power like nuclear)

Gas is faster to respond, coal, not so much.

From the Goog:

Starting up a coal-fired power station depends heavily on the plant's current temperature, taking anywhere from 2 to 48 hours to reach full operational capacity. Because of massive metal boilers and turbines, the heating process must be slow to prevent severe thermal fatigue and equipment damage. [1, 2] The startup time is broken down by the plant's previous state:

  • Hot Start (less than 8 hours offline): 2 to 4 hours. The boiler and equipment are still warm, allowing for a relatively quick resumption of steam production. 
  • Warm Start (8 to 120 hours offline): 4 to 8 hours. 
  • Cold Start (More than 120 hours offline): 12 to 48 hours. The plant must be heated from room temperature, which involves initially burning expensive natural gas or diesel just to safely warm the furnace and metal pipes before coal can be introduced. [1, 3, 5]

To explore how these heavy thermal operations impact the broader electricity supply, you can review the U.S. Energy Information Administration's grid reliability data or dive deeper into the technical challenges via the Environmental Protection Agency's Coal Startup Report. [6] If you are interested in the broader power market, let me know:

[1] https://www.quora.com/Why-its-not-that-easy-to-start-operati...

[2] https://www.quora.com/How-long-does-it-take-for-a-thermal-po...

[3] https://www.epa.gov/sites/default/files/2015-11/documents/ma...

[4] https://www.quora.com/What-is-the-minimum-time-required-by-s...

[5] https://www.solarquotes.com.au/blog/inflexible-fossil-fuels/

[6] https://www.eia.gov/todayinenergy/detail.php?id=45956

Re: Solar generates more energy in US than coal for first time

#63

Post by mbgerring » Thu, Jun 11, 2026, 6:06 PM UTC

thelastgallon wrote: post #35

This administration is hitting milestones without even trying!

No, the clean energy industry is doing that, it’s a large and growing industry with billions of capital deployed and millions of people working hard across technology and policy to make it happen.

Re: Solar generates more energy in US than coal for first time

#64

Post by trial3 » Thu, Jun 11, 2026, 6:07 PM UTC

arbitrary_name wrote: post #46

trial3 wrote: post #28

Earlier quoted context omitted.

i think it’s kind of the opposite: balcony solar is good for power companies in the same way that them asking you to turn off your lights is good for power companies: if each customer is using less overall power they can serve more customers with existing infra. that obviously depends on time of use and the sun etc, but balcony solar in the USA can’t come fast enough. my electricity in NYC is almost $.40/kWh, a limit…

i think that is an overly simplistic axiom: the utilities must cover a fixed asset base (poles and wires and transformers), pretty much regardless of how much or whether a household consumes from the grid. the less the utility recoups via billing for energy usage, the bigger the deficit to cover their fixed network costs. they are frequently interested in having you consume energy, to help defray those costs, especia…

that’s true, i was considering only the perspective of the major city i live in rather than networks with lower ratepayer densities where the economics are probably totally different

i do think “fully consumed or gated to never backfeed balcony solar at scale” is all i’m referring to, which i naively hope is a smaller regulatory change than backfeeding

Re: Solar generates more energy in US than coal for first time

#65

Post by harmmonica » Thu, Jun 11, 2026, 6:07 PM UTC

Filligree wrote: post #41

harmmonica wrote: post #22

Question for those in the know... See lots of press about balcony solar in Germany, and California recently introduced a bill to allow it (I'm guessing other states already allow it; not sure if the CA bill has a chance of becoming law). But how far are we from a more plug and play home solar system that becomes a primary energy source as opposed to a limited secondary source? And what are the issues with it actually…

There’s a legit grid stability issue for solar in general, balcony or no. Usage varies second by second, so the grid relies on physical inertia in the form of rotating turbines. Panels have no inertia; therefore, the more you have the less stable the grid gets. That is however something which can be fixed by grid-scale batteries. Or home systems, for that matter, if they have batteries and some equivalent of Victron’…

Ah, this is why I come here. I had no idea that was the case. I feel like there was a story going around recently about how hard it is to restart some power generator if it gets knocked offline. Maybe it was about Hoover Dam now that I think about it (i.e., how bad it would be if the Colorado gets too low).

Re: Solar generates more energy in US than coal for first time

#66

Post by oblio » Thu, Jun 11, 2026, 6:08 PM UTC

flumes_whims_ wrote: post #49

onlyrealcuzzo wrote: post #42

Earlier quoted context omitted.

Contrary to popular belief, solar panels don't generate zero power on cloudy days. They typically generate 10-25% of their maximum output on the cloudiest of days. Most cloudy days are not maximally cloudy. We don't need solar panels everywhere to get even close to ~100% renewables (with nuclear, wind, new geothermal, and hydro). The areas where you put them are distributed enough that it would be exceptionally rare…

But they do generate zero power at night.

And people use less energy at night. Yes, they do need heating/cooling and a few other things at night, but the peak is during the day and in the evening.

This argument is almost closed at this point, with PV + batteries being quite price competitive. We're no longer in 2018.

Re: Solar generates more energy in US than coal for first time

#67

Post by TremendousJudge » Thu, Jun 11, 2026, 6:09 PM UTC

computerdork wrote: post #45

thelastgallon wrote: post #38

Earlier quoted context omitted.

US consumers and businesses buy almost all their stuff from China. China's massive footprint of Coal should be added to US emissions.

Good point. But one factor is China is also greatly reducing their emissions. For instance, their pollution levels have plummeted after enacting strict controls: https://epic.uchicago.edu/insights/china-has-quickly-and-sha... Still, that is a good point, a lot of the emissions from manufacturing have been shifted to other countries.

>China is also greatly reducing their emissions

Are they? because looking at these charts[0], although fossil fuel use as a percent of total energy may be going down, the absolute values for coal, gas and oil only go up year over year.

[0]https://ourworldindata.org/profile/energy/china#what-sources...

Re: Solar generates more energy in US than coal for first time

#68

Post by mbgerring » Thu, Jun 11, 2026, 6:09 PM UTC

I work in clean energy, and whenever I read comments like those in this thread I realize there’s so much that I take for granted that is still relatively unknown outside my bubble.

It's somehow still early innings for the energy transition, and there are a lot of fun engineering problems to work on. Join us, start here: climatebase.org

Re: Solar generates more energy in US than coal for first time

#69

Post by colechristensen » Thu, Jun 11, 2026, 6:10 PM UTC

harmmonica wrote: post #22

Question for those in the know... See lots of press about balcony solar in Germany, and California recently introduced a bill to allow it (I'm guessing other states already allow it; not sure if the CA bill has a chance of becoming law). But how far are we from a more plug and play home solar system that becomes a primary energy source as opposed to a limited secondary source? And what are the issues with it actually…

>how far are we from a more plug and play home solar system that becomes a primary energy source as opposed to a limited secondary source?

We don't need a more plug and play system. A zero agreement interconnection for whatever UL certified 300W-ish scale is fine and should be widely deployed.

There needing to be interconnection agreements with your utility and an inspection is not a blocker that needs to be removed. Most places require a licensed electrician for complex work, having the electrician fill out a form and having a utility inspection is how things should be.

Re: Solar generates more energy in US than coal for first time

#70

Post by harmmonica » Thu, Jun 11, 2026, 6:10 PM UTC

davidw wrote: post #52

harmmonica wrote: post #22

Question for those in the know... See lots of press about balcony solar in Germany, and California recently introduced a bill to allow it (I'm guessing other states already allow it; not sure if the CA bill has a chance of becoming law). But how far are we from a more plug and play home solar system that becomes a primary energy source as opposed to a limited secondary source? And what are the issues with it actually…

Utah passed a balcony solar bill; I think they're the only ones so far. Oregon tried in the short session last year, but it got shut down by fire marshall type people, sadly.

Interesting on Utah. Re Oregon, was the fire Marshall acting in good faith in that scenario? Recently reading about fire-truck size in the US I start wondering what the motivation is for some views about things around fire safety (amongst a million other things). Maybe good faith is too cynical. Maybe just hard-to-change attitudes.