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Comment by immibis | Hacker News Reader

Solar energy is currently the cheapest form of energy, cheaper than coal, cheaper than natural gas. You know the conspiracy theories about how the oil companies are keeping perpetual motion machines hidden? Solar panels are literally that. With the caveat that they only work in sunlight. So they're not great when you need energy at night. But even if you triple your costs to account for only working 8 hours a day, they're cheaper than anything else.

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For a lot of industrial processes, being limited to running during sunny periods would cause costs to go up by a lot more than a factor of three. The grid scale storage necessary to make solar power work for heavy industry remains extremely expensive and capacity limited. Costs are starting to come down but it will take decades.

Solar + battery is now the cheapest. Except in the USA, where natural gas is heavily subsidized. Happily, deploying new gas plants is constrained by supply of turbines. So solar + battery wins by default.

Batteries (plus all the other associated equipment and maintenance) are hardly cheap in the quantities needed to keep heavy industry running 24×7. Battery storage holds promise for the future but so far it's only been used on relatively small demonstration projects. And some of those have been plagued by fires and outages.

> relatively small demonstration projects.

California has got really good at building giant batteries - At peak times they provide 30% of the state’s electricity (https://www.economist.com/united-states/2025/05/22/californi...) - The Economist.

California is the 4th largest economy in the world by the way. A bit larger than a “small demonstration”.

https://ember-energy.org/latest-insights/solar-electricity-e...

https://www.volts.wtf/p/solarstorage-is-so-much-farther-alon...

What's your next objection?

I don't have any objection, I'm just stating a reality: it's going to take decades to build out enough battery storage to make renewable energy practical for the base load required for heavy industry. This stuff doesn't scale up quickly regardless of costs or incentives. The places where battery storage is used today generally have high electricity prices and low industrial capacity. If we want to have cheap stuff then we need to have cheap electricity (and cheap industrial heat) available to make that stuff 24×7.

> Solar energy is currently the cheapest form of energy, cheaper than coal, cheaper than natural gas.

Cheaper before the incentives?

Yes. Even if you count the fossil fuel subsidies.

Can you share the source? I’m very curious.

First search result: https://www.scientificamerican.com/article/wind-and-solar-en...

For some reason, these savings never cascade down to the consumer. Solar energy is typically a surcharge, not a cost savings.

When I log into my utility account, I can opt into solar generated power for X $/kwh more, not less.

Solar is also the most democratic, as long as you can tolerate it not working at night. I encourage you to experiment with a small portable system. I did - a 30W panel, 9Ax12V SLA battery, off-the-shelf car inverter, packet of crimp connectors, spool of wire, crimp tool, the cheapest over-voltage shutoff controller I could find (just search for solar charge controller - although lead-acid chemistries are moderately tolerant to charging out of bounds, unlike lithium, which is why I suggest lead-acid).

I really think home battery power is going to be a standard feature in the near future. Like indoor plumbing and central HVAC.

My utility just adopted time of use billing and by my napkin math a battery system with one day of capacity will pay for itself in 5 years. And that’s without solar at all. The additional solar panel cost would pay off in under 3 years. And I have cheap electricity.

Yeah main issue is elasticity. But otherwise promising. China is adding insane solar capacity yearly so I guess they see it as promising too.

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