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Understanding Solar Energy

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261 points chmaynard | 1 comments | 20 Mar 25 12:09 UTC | HN request time: 0.347s | source
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pfdietz ◴[20 Mar 25 12:29 UTC] No.43422192[source]▶
The bit how about incredibly quickly PV has grown is a figurative slap in the face to Vaclav Smil. He had just ten years earlier said PV wasn't going to grow quickly because historically energy replacements took a long time.

https://vaclavsmil.com/wp-content/uploads/2024/10/scientific...

This retrospective on Smil's predictions four years ago is notable:

https://www.quora.com/Is-Vaclav-Smil-right-in-his-criticisms...

"To get 1 PWh/year of electricity you need to install about 450 GW worth of solar panels. You need dozens of years to acomplish such task. Reality check: 3 years in current speed, in the future probably faster."

Indeed, as the thread top link shows in 2024 the world installed 595 GW of PV.

As John Kenneth Galbraith said, "If all else fails, immortality can always be assured by spectacular error."

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looofooo0 ◴[20 Mar 25 14:41 UTC] No.43424155[source]▶
What people tend to forget is, that coal, oil and gas are all restricted by mining or drilling as the old are consumed, and it gets harder to access new oil wells etc. For PV there is no such limit (only copper basically, but this is recyclable and aluminum can do many tasks.) For batteries, there is lithium (lifepo4) and even that is questionable (sodium batteries) and again there is the potential for recycling. Hence, I do not see anything stopping the exponential growth of PV and batteries.
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Ringz ◴[20 Mar 25 14:55 UTC] No.43424310[source]▶
You are right.

But one misconception I often read is that everyone focuses on batteries. It would make more sense in general to talk about energy storage instead of just batteries. Like Kinetic, chemical, thermal and so on.

Batteries cannot be solely responsible for back-up. You need different types of storage: short term, medium term and long term storage.

There are different concepts for each application. Batteries, compressed air storage, pumped storage, kinetic, thermal storage as well as power-to-X systems are able to absorb the increasing summer power and provide the energy again in the medium term or seasonally shifted.

https://doi.org/10.3929/ethz-b-000445597

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bryanlarsen ◴[20 Mar 25 15:19 UTC] No.43424569[source]▶
There are only three energy storage forms that are relevant for the next decade. All the others looked promising, but the learning curve on batteries has rendered them irrelevant. Your link is from 2020, it is out of date.

The best energy storage form is "final form". Some energy products can be stored. For example if you are using the energy to create heat, you can store heat for use in the future. Heat storage sucks as a way to store energy destined for electricity, but is a great way to store energy destined for use as heat.

The utility of batteries for daily storage is obvious and well proven.

Thirdly, the best annual storage is pumped hydro. It's the cheapest and it can be used pretty much everywhere -- all you need is water at one end of an elevation change and a way to build storage at the other end.

All the other forms that you'd think would fit in between the two are being quickly subsumed by the rapid price drops in battery pricing. The cutover points are rapidly shifting -- batteries are now cheapest for biweekly-ish.

And the primary sources are getting so cheap that overbuilding is an alternative to storage. Rather than storing for the reduced amount of daylight in the winter, just overbuild. More overbuilding and a few days of storage will let you handle a stretch of cloudy, windless days in January. No annual storage required.

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1. Ringz ◴[20 Mar 25 16:44 UTC] No.43425560[source]▶
Don’t get me wrong—I’d be all for batteries ruling the world if they were both affordable and technically advanced enough to meet various demands. That means they shouldn’t degrade too quickly, for example, when capturing and releasing wind energy in milliseconds. Or they shouldn’t lose too much energy over time due to self-discharge. Or they should be able to supply large amounts of energy instantly. Overbuilding is also a valid approach, especially in connection with a smart grid spanning multiple countries. All of that is fine.

However, the point of the study is different, and that makes it still relevant today: The barrier to expanding energy storage isn’t a technical one—it’s a political one. The study also shows that there is a great deal of variability, and the often-used argument that there’s not enough lithium or rare earth elements doesn’t hold up. More recent studies validate different storage technologies depending on their specific use case, showing that they can complement batteries in a meaningful way—also from a financial perspective.

Another perspective is that we still have a long way to go before full electrification. Right now, batteries are used in suitable scenarios, but many other areas haven’t been electrified or optimized at all. Other storage technologies might still become relevant. Building a house around a 20,000-liter tank to store energy for heating in Alaska over six months might already be financially and technically viable. But whether the logistical challenges of such solutions will ever make them truly feasible—that’s something I neither want nor can predict.