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Comment by TeMPOraL | Hacker News Reader

A question I'd like to see answered: are solar panels net energy producers? I.e. over their lifetime, do they generate more electricity than combined energy that went into manufacturing, transporting and deploying them, including the marginal energy costs of mining the necessary substances they're made of?

Because if not, then they're a net waste.

I'd like to see a similar analysis on emissions instead of raw energy too.

It's not that I think solar is bad; it's just I don't understand why discussions about energy and emissions never include end-to-end accounting of energy costs & emissions.

EDIT: Yes, I am lazy; in the Christmas fever I forgot about the term "EROI", though I still see it discussed too rarely. But yay, thanks people for jumping to conclusions and accusing me of motivated reasoning and/or sowing disinformation. -.-

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5-6 years ago the energy needed to produce panels compared to their energy output reached parity. Now the energy needed to produce panels is 6-40 times less than a life time output of the panels. Today the energy input for producing and installing panels is less than the there energy output in most places. And with the efficiency gains in production of the panels and the efficiency gains of the panels electricity production every year the equation is getting better. As the world moves towards a energy mix with more renewables every year the solar power becomes cleaner. Where as most fossil fuels power production has stagnated and has little or no improvemets. With big oil and car companies spending money on politicians to not improve efficienies and decrease production.

With sustainable energy winning so clearly, it's getting more expensive to corrupt polititians though. I never thought China would be a great example for this.

And don't forget the improved energy mix that is feeding the manufacture of these panels. Within our lifetimes it may become possible to manufacture and install solar panels with mostly renewable energy.

This is the right question.

A few years ago I worked for a wind turbine company (Admittingly a crappy one) and I was one of two software engineers,

My first job was to analyse all of the data about 300 turbines were sending back home, and build a dashboard.

Well a few weeks later after checking all of the data, it turns out that the entire fleet of turbines actually consumed slightly more energy than they produced.

This was because of many manufacturing problems meant there were several frequencies that the turbine couldn’t spin at because it would generate a resonance and shatter or break something. So the system was frequently applying the break to stop the turbine destroying itself.

After several days of head scratching and double-checking and triple-checking the data, I went to the mechanical engineers and they finally sheepishly admitted they knew these things were net energy consumers rather than producers.

This doesn’t even take into account the energy budget of cost of production and distribution.

This isn’t the case for the big turbines you see out in the field, I’m really just reenforcing the parent comments point that total energy needs to be considered.

Why was applying a brake so energy intensive? Seems like it'd be practically free.

In general, turbines use energy to start up! They need to do this in order to overcome the very large inertia. Imagine a wind that lasts for 4 hours, but to harness that, you need to be spinning up for 1 hour, leaving you only 3 hours or useful energy. Instead, they spin up the blades to the optimum speed and can get payback for that initial spent energy.

Also, you still need energy to run the computer that monitors everything.

https://oilprice.com/Alternative-Energy/Wind-Power/How-Much-...

After braking the turbine isn't generating the energy it needs to in order to be net positive.

For this to lead to a net negative, it has to be more than just a lost opportunity to make energy: either it is a significant energy consumer (i.e. not just a dissipater), or the turbines must be incapable of producing significant amounts of energy even when working correctly. There is something that has not been explained here.

That the turbines were incapable of producing significant amounts of energy even when working correctly, is not out of the really of reason.

How bad would it be to insert a comment about regenerative braking here?

But yeah, that sounds so bizarre. The Emperor's New clothes territory.

Regenerative braking is not an issue here. Wind turbines slow down the wind to generate electricity, so, in a sense, they are always doing regenerative braking when operating as intended. They would only be mechanically braked when this (and also blade feathering) is insufficient or inapplicable for some reason.

If this is common, then it's very bad news.

Its common for small (house mounted) turbines to not generate their embodied energy, which is why you don't really see them any more.

Edit: Reference https://www.resilience.org/stories/2010-09-16/real-world-tes...

It's not. His comment is about a specific company who made faulty products, not about wind turbines in general.

I've read stories like that, people rushing products to benefit from subventions. It backfires badly on renewables.

What the turbines use the energy for?

You are cherry-picking a bad example.

I specifically explained that my story was not applicable to the big turbines and then explained that my anecdote was a call for critical examination of data, it was not intended as a generalisation of the technology as a whole

Even if he is then it still shows that it's not as rosy as many likes to claim.

What's not as rosy as many claim? There is simply not enough data in the comment to draw conclusions about anything apart from a specific unnamed producer of faulty products...

It's pretty decided that Solar will never be able to produce even close to sufficient energy to serve as a baseline energy source.

Including all losses, to power everything in the world with solar it comes to around twice the area of Portugal with current tech.

That's utterly wrong. How could you come to that conclusion?

How can you come to another conclusion by all means. Convince me that solar can serve as a base powersource.

~20 terawatts = humans

~90,000 terawatts = sunlight hitting surface of earth

Yes now put in the missing part. What is the maximum effeciency we can hope for and what is the areal plus inventions that needs to be done, the cost and the environmental consequence of large solar farms etc etc. fusion has a much better chance of being a reality than solar or even solar and wind together. You are living in a fantasyworld.

Lets not look at the maximum we can hope for ever. Lets look instead at figures for what is commercially available now. So, say 27% maximum conversion.

Average insolation gives us ~6kWh over a square meter over a day, 27% of that gets us to 1.62kWh, divide by 24 to get the wattage, that's a 67.5 watts per square meter average before we get to storage or transmission.

HVDC has losses of ~3% per 1000km. Now lets look at round trip efficiency for storage. Typically you see a quoted figure of around 70% depending on technology type. So lets say a 65% loss (edit - this should read 65% efficiency, or alternatively a 35% loss) from storage and transmission.

We are now at ~44 watts per square meter, which gives us 456,000 square km from the 20 terawatt rating of humans. So ~5 Portugals, which is admittedly higher than my original figure of 2 Portugals, though you would presumably site your panels somewhere that gets better than average insolation, places like the Sahara, for example.

Also, for comparison, the Sahara desert is ~100 Portugals and the area currently used by humans for agriculture is ~550 Portugals.

And nuclear can do 1000w per m2 just to put things in perspective here and that's currently.

Now add to the problem of solar that it's unreliable, we haven't actually solved creating proper fuel cells and have no proper grid to distribute it through which is why ex. Denmark had to get their energy from the Germans this summer because Denmark who is based most on wind didn't get any wind and had to get from Germany who didn't actually use solar but instead coal. So you would need to actually solve that kind of problems too which we aren't even close to.

In other words. Whatever reality you or others imagine with solar or renewables you are far away from showing anything close to it being a realistic solution.

I am all for renewables but let's make it support a more fundamental and solid energy base like nuclear and then add solar on top instead proposing an inferior energy form when betters are out there.

[flagged]

Fusion has pretty much no chance of being a reality, in the sense of being economically competitive. And this has been known for more than 35 years.

http://www.askmar.com/Robert%20Bussard/The%20Trouble%20With%...

(See? That's how you give a reference to back up a claim.)

And yet the Chinese just succeded with an important step.

You are using something written in 1983 as your support enough said.

If someone's argument is that something is wrong and has been known to be wrong for a number of years and here is an article explaining why, you cannot really use the fact that the article being used as explanatory evidence has been around for the amount of years stated, as some kind of winning move against their argument.

You do know this, right?

Yup, I also know that we are actually seeing progress in that field because the Chinese are investing in it and which then obviously needs to be factored in like everything else.

The point was that fusion is as far of as 100% solar is. So again unless you show some actual proposals for how to get 100% solar to work realistically you are in no better position than the Fusion crowd is.

I'd be interested to know more about the Chinese research you are referencing. Could you point me to the research and explain how it overcomes those arguments of Lidsky? Is it using something other than Deuterium and Tritium, or has it found a way around the problems that Lidsky enumerated with the DT approach?

He's probably referring to this:

https://www.universetoday.com/140540/chinese-fusion-experime...

It's nothing very notable.

That thing is interesting for plasma physics though. It isn't really trying to be a fusion reactor, as far as I can tell from following the links past the article. Is more of a scaled down testbed. I have often wondered if the people working on tokomaks are more interested in the science you can do with them, than the potential for generating electricity, even if the people providing the money aren't entirely aware of this.

Its a step toward solving how to control the plasma. So yes its a pretty important step.

Better plasma control doesn't do much to Lidsky's argument though, if you have a look through it.

The Chinese succeeded at something that doesn't do anything to address the devastating, fundamental argument Lidsky gave back in the 1980s.

Lidksy's argument is as valid today as it was then.

They succeeded in one of the steps toward a solution.

How far is wind and solar with realistic fuel-cells?

https://steelguru.com/metal/korea-zinc-installs-ess-to-power...

https://www.ewe.com/en/media/press-releases/2017/06/ewe-plan...

In other words. Not far.

When you write "EWE plans to build the world´s largest battery" you know you are dealing with PR not with reality.

Lets see how well that theory goes up against recent history.

---

Tesla to build world's biggest battery

https://www.telegraph.co.uk/technology/2017/07/07/tesla-buil...

Tesla mega-battery in Australia activated

https://www.bbc.co.uk/news/world-australia-42190358

---

Hyundai Plans World’s Largest Grid Storage Battery In Korea

https://cleantechnica.com/2017/12/05/hyundai-plans-worlds-la...

Hyundai Electric completes world's largest ESS

http://komec.kr/eng/Board.asp?menucode=0503010000&mode=2&no=...

---

I don't think Korea Zinc or the people of Adelaide are storing their power using public relations. I think, in reality, they had a battery delivered.

Again not far. Fuel cells to be used that allow for storing solar reliably, by all means, provide the evidence of the fuel cell industry making this possible not wishful proprietary technologies

>provide the evidence of the fuel cell industry making this possible

Hang on, so, you want fuel cells but dismiss someone building the world's largest battery using redox flow technology?

I take it that you don't know that redox flow batteries are a type of reversible fuel cell? https://en.wikipedia.org/wiki/Flow_battery#Redox

I want fuel cells at scale that can work anywhere just like batteries, otherwise you dont have a useful solution to the already utopian all solar world you guys dream of.

That would be cheap redox flow batteries, like the EWE project I linked you to.

One thing, I take it you don't see lithium scaling. Why is that? There is enough of it.

Small turbines are rubbish. Always have been. Wind turbines are a swept area game. Everyone in the industry knows this.

It's uncited and anecdotal.

EROEI calculations are hard to do and even harder to compare accurately, because you have to decide what second and third order effects "count". Most reliable ones I've seen put the lifetime output at 5x to 10x the input. This is actually better than some of the unconventional oil extraction methods.

And those calculations are done assuming the PV modules are made in the same place they are installed, like, say, Germany. But there are places in the world where the solar resource is 2x better. In those places, the EROI would be even better.

This does lead to an interesting observation: in a solar-powered world, heavy industry is going to move away from places with less sunlight. Good for the low latitude countries, not so good for Europe.

Yes, right now they do have a carbon footprint but it is far lower than fossil fuels.

In the future - when production is done with green energy - that will get far lower.

https://www.mnn.com/green-tech/research-innovations/blogs/ho...

https://www.euractiv.com/section/energy/opinion/mondaycop22-...

Not sure if your links answer the question. They mention "30x less carbon footprint than coal" not that they are not net waste all things considered. Which is a very different question.

And "carbon footprint" is not the only thing that matters either. If your process involves tons of heavy metals, that's a lot more relevant in soil pollution than carbon.

It's nothing even comparable to coal? Have you seen how much of that stuff is actually burned per kw/h? It's absolutely insane if you've seen it. Especially when you imagine the logistics involved (or in my case have been shown the logistics involved in only a very small case, which was already shocking for me).

Not sure why you are coming back on coal. Thats is not my point. My point is that the link does not give any support to whether or not solar panels are net waste energetically speaking. Its fairly obvious that they are probably much better than the worst fossil fuel, but that does not answer the original question raised.

Even if they had zero carbon footprint, they could still be a waste.

If making them uses more energy than they'll ever produce, you might be better off just using that enery to charge some batteries and then use the batteries in place of the solar cell.

Except batteries waste energy as well. You never get 100% of what you put in.

I am sure someone here knows the exact percentage but my personal experience with lead acid and solar panels leads me to the opinion storing then converting solar energy from DC to AC wastes 80% or so of the total produced

My workshop I am building will run on DC 12 volts and have 3k to 4k or so of solar panels and another 2kw of baby wind turbines because of what I learned dabbling with solar power.

That sounds really neat.

Did you DIY all the solar and wind installation? Any pointers to resources about that stuff that I'm not likely to find easily by googling?

All DIY

Lead Acid batteries are ok

Keep the charge high on the batteries, the higher you keep it the better. Down to 10 volts is hard on them.

Used forklift batteries are a good large battery

for wind which creates a high surge you want a battery regulator setup instead of the standard solar controller

http://hydrogenappliances.com/batteryregulator.html

I really think generating hydrogen under pressure with electrolysis would be a viable storage of non used electricity but I have yet to build that system

Ah no you are taking physics principle of energy can not be gained only transformed but discounting sun energy in your calculations which is another input. Solar panels were a waste in energy terms 10 years ago. Today that is no longer the case. https://phys.org/news/2016-12-solar-panels-repay-energy-debt...

Good and interesting question, and I would like to know too, but a couple of points here

- You probably meant to say this but, obviously, there has to be a usage time variable in the calculation somewhere. They will presumably have a lifespan where they can be deployed outdoors without replacement/maintenance, and perhaps this lifespan itself but certainly the average hours usage per day will then vary with climate. There might be tradeoffs in the design and materials used which increase durability but lower yield, but then affect energy required to produce, etc, etc. My point is that it's really quite complex and I'm quite sure there is no one answer, especially with the technology changing (improving) all the time.

- You have to walk before you can run. Even supposing there is a deficit today, the only way we get to a future where there is an energy surplus with solar tech is by deploying the not-good-enough-yet tech today and improving it through iteration to the point where it is good enough. Again, then whether it is worth pursuing or not depends a bit also on that (predicted) rate of improvement.

https://phys.org/news/2016-12-solar-panels-repay-energy-debt...

A lot of the people who mention EROI are basically conspiracy theorists, and the basic math they use makes no sense.

This website debunks some of the stuff that you'll find if you just blindly Google EROI:

http://bountifulenergy.blogspot.com

However, even the crazy people generally aren't claiming that solar panels are net negative.

It‘s called EROI and information is widely available.

> are solar panels net energy producers?

Yes (based on data from 2008). See at the bottom, under Mythconceptions: http://www.withouthotair.com/c6/page_41.shtml

Producers make profits by selling solar panels. Customers save money by buying solar panels.

Unlikely that this would be the case if solar panels were not net energy producers.

That's a very bad assumption. Producers and customers make money exploiting price differentials on the market; this is not strictly tied to whether or not a product is a net benefit on a global scale.

Hence I was asking about EROI calculation.

> Producers make profits by selling solar panels. Customers save money by buying solar panels. > Unlikely that this would be the case if solar panels were not net energy producers.

> That's a very bad assumption.

if you assume efficient and free markets, then this is a good assumption. If it takes more energy to create a panel than it's (average) lifetime energy output, consumers will find that it saves no cost, and thus would not buy them. Producers of panels will either have to work out how to reduce costs (or improve yield) to a rate which will net a return that the consumer considers worth investing in a purchase.

So by the fact that panels exist today, it _must_ necessarily already have passed the threshold.

Efficient and free markets is a wrong assumption. Those almost never exist in real life.

(And it's not just the fault of regulatory overreach; if a seller or a buyer are exploiting information asymmetry, the market isn't efficient by definition.)

Government subsidies? Works for sugar industry.

There are actually large tariffs on solar panels.

Supposedly it's to protect the nascent solar industry in the US. In reality they're there to help incumbent oil/gas/utility interests.

And nuclear - much like the registered lobbyist who wrote this article.

Your apparent inability to do a simple search makes me think you just want to send us on a wild goose chase proving everything from first principle, or alternatively to saw some FUD around solar technology.

I mean, what answer are you willing to accept? Here's one investing as much energy as your question:

Yes, solar power is net positive.

why not google it? The answer is widely available.

Or are you “just asking”?

> why not google it?

Two reasons:

- the quality of information available in HN discussions is usually much better than whatever you can find in the first couple of pages of Google search results. It's usually more up to date, and usually presented with less bias.

- setting aside the quality of search results, the time needed for a person without much knowledge about the topic to look through dozens of pages can be actually a full afternoon of work (which would be prohibitive on a day such as today); on the other hand, people who are familiar with the topic can provide an answer in a few minutes.

> Or are you “just asking”?

Please don't do this. I'm not a mod or anything, but I actually quite like the guidelines here - and the relevant point is near the top of guidelines:

> Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.

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