Semi-transparent solar panels allow concurrent production of crops and power | Hacker News Reader

Semi-transparent solar panels allow concurrent production of crops and power

onlinelibrary.wiley.com

218 pointsrch223 comments

My mother ayed tomatoes in the spring when it was still cool. She covered them with clear plastic bags as she always has. But she needed one more bag so she used a blue recycling bag on one of the plants. Blue tinged really it's almost clear.

I pointed out to her one of the plants had yellow leaves. It was the plant with the blue bag.

Later in the summer the blue bag plant produced fruit just like the other plants. But the bottom of each tomato was disfigured and looked rotten but it was dry to the touch. It's blossom rot due to low calcium. I have to wonder if it was the blue bag or lack of/too much water. All the plants got the same nutrients only this one had the blue bag. It got red light and green light which plants don't need but no blue light.

Plants are seemingly very sensitive to sunlight quality. I'm sure the solar panels are clear but even a slight colour blockage may be harmful.

It was an interesting result.

The ratio of red and blue light controls various functions of a plant. In the context of aquarium plants, more red light makes them get tall and leggy, more blue light makes them be compact and bushy.

https://gpnmag.com/article/effects-of-blue-light-on-plants/ talks a bit about it in the context of greenhouses and tomatoes, the picture in the middle shows 6 plants grown with wildly different red/blue ratios.

If the balance of the light coming through your solar panel was problematic, you could always filter out some of the overabundant light.

Is that how they know how close to the surface of the water they are?

That slight colour blockage, or the tint those solar panels have is helpful.

There are two reasons. One, plants grow better under red light. Red light has the highest efficiency for photosynthesis in plants, that why LED grow lights are tuned for certain wavelengths. Plants use blue light to know what direction to grow.

And for a certain category of tints or dyes that are fluorescent, additional red light.

Luminescent solar collectors have an embedded dye with molecules that fluoresce, that give off even more red light.

Example: http://www.soliculture.com/lumo-technology/

Is that why indoor LED growing lights have that purple-ish tint to them? I never knew that. I knew about the red, but never the blue. You're awesome. Thanks so much.

Here's my source material: https://youtu.be/Y1nlQ6bGX4c?t=4018

All of my plants this year have gotten blossom rot, pretty much too late to fix too. No tomatoes for me this year.

Blossom end rot is caused by calcium deficiency. Easiest solution for this is to just crush up egg shells and put them in and on top of the soil. I save my eggshells in a jar in the fridge for a few months prior to planting. It may be too late for this year but should work wonders for you in the future.

Seconded, I would do this with my mom each year in her garden when I was a kid. Works 100% of the time, and it's a non-invasive way to address the issue.

Not always. Sometimes it's because it's too hot at night.

I had deformed cumquats from my tree until I started blending egg shells in the spice blender and watering them into the tree base.

A blue plastic bag filters most of the spectrum EXCEPT the blue part. Not the other way around. Simple proof: look inside, the light is blue.

I guess the biggest problem for the plant here is that especially the infrared part of the sunlight is very important. Yellow leaves usually mean not enough light. Especially tomatoes need lots of sunlight.

Nope. If the bag looks blue that means it's scattering away blue light while letting the rest through. So it's filtering (out) the blue. OP is right.

If you see blue on BOTH the outside of the bag and the inside, what does that mean? I’ve never thought of this.

It means some blue goes through, some is reflected.

As a guess, perhaps the unfiltered light that gets through goes through a phase change from being reflected. https://en.wikipedia.org/wiki/Reflection_phase_change

No, a blue filter, like a blue plastic bag would let blue pass and absorbe the other colors. That's why if you shine a white light through a blue filter, things look blue on the other side.

Now, some of the blue light is scattered away, and that's why you see the plastic bag itself as blue.

Hang on, so if you shine a white light through a blue filter, the light on the other side looks blue. And the filter itself still looks blue on both sides. But then, where did the non-blue component of the light go?

Converted to heat. What's going on here is a discussion about transmission and transmittance. [1]

[1] https://www.swiftglass.com/blog/key-differences-transmission...

Imagine looking at this blue-transparent bag with a red light, it will appear more opaque.

Just like laser light protection goggles.

Only people who spend most of their life in densely crowded cities could think that the planet has so little space that you'd need to grow crops underneath solar panels for efficiency's sake.

Indeed. This reminds me of the "let's drive on top of our panels" stupidity. I suppose it could have practical applications in space colonization.

A lot of farmers are leasing their land to solar developers because it provides guaranteed, stable payments.

Though "we" as a whole are not limited by land, individual economic actors are limited by how much land they own.

Additionally, interconnection to the grid and node congestion are becoming larger percentages of the cost of solar, since they are roughly constant as the cost of solar plummets. Farms are somewhat ideal for medium size solar installations because they often have significant existing grid connections that are underutilized.

Now that we have economical solar tech, the actual implementation of solar installs will be highly dependent on regulations, economic motivations of individual economic agents, the knowledge and intelligence of thistle agents, and combinations with existing infrastructure. (For example, we are seeing batteries being installed in old fossil fuel plants, so that we can reuse those super expensive grid connections.)

It's not "need" as much as increasing efficiency and profit. There are at least a few studies now that have shown that multipurpose use for both agriculture and solar will provide greater output than doing only one; for example you may lose 30% of maximum potential solar production and 40% of agricultural output, but it's still not >50% loss for either. These studies were not performed with this type of semi-transparent as in this article, so perhaps the boost could be larger, if the additional cost of the panels is not too high.

From the abstract:

>up to +2.5% for basil and +35% for spinach

There's a reason for this: Spinach cannot tolerate mid-summer heat, and doesn't need full sunlight. Was told this by local organic farmers here in coastal SoCal -- and because my own backyard plantings turned yellow and died.

1. Agriculture is one of the main causes of deforestation.

2. Many plants are already grown in greenhouses.

I do worry somewhat about devastating desert ecosystems by paving over them with PV panels, but we're so far from that being a problem right now.

Depends on the desert ecosystem.

Most desert ecosystems have a wretched excess of sunlight, and lack moisture.

Solar panels treat both of these: they capture a lot (but by no means all) of the sunlight, and serve as a nice, concentrated condensing surface for dews.

You can see this at a panel farm in dry areas: there's often a nice row of green in front of each panel, precisely where the condensing dew drips off them onto the ground below.

Deserts aren't necessarily things to be "treated." We definitely don't want the entire world to be a desert, and the growth of the Sahara is somewhat troubling because of what it signals, but saying they have a "wretched excess of sunlight" and are fit to be exploited by humanity is the same attitude that got us in our current energy predicament.

And only someone blind to the ecological damage that agriculture does would regard all that land as free to use by humans, without consequences.

Here [0] is a map of the world's remaining wilderness. Notice how it's nearly all desert, with the exception of the Amazon rainforest. And hey, guess what's happening to that?

We are short of space. And time.

[0] https://images.theconversation.com/files/256144/original/fil...

Granted that the desert is effectively ideal for solar panels, and less useful for agriculture.

An interesting application of this technology would be building solar arrays along the edge of advancing deserts, with shade-tolerant plants with the sort of root systems which have been shown to halt and reverse desertification.

It's easier to do good things (such as halting the inexorable spread of the Sahara) if the operation is revenue-positive. Even though this would be more labor and less energy than just putting up a panel farm and calling it a day, it's more of a return on investment than the big old zero you'd get from just planting to try and fix dunes.

Financialized, high output agriculture drives that, not farming in general.

Deserts are a perfect place for greenhouses as well as solar panels. Just not both of them combined. That concept might make sense in very densly populated areas, where people want to use the most out of their garden greenhouse. But on industrial scale, I am very sceptical, the efficency should be a lot higher to justify the building costs and increased complexity.

Nuclear power is a thing.

“wilderness” is defined as places generally untouched by people at all, not land that is unused. The vast majority of the unmarked areas of that map are still unused.

What's the definition of wilderness used on this map? The only wilderness area on the map that I've been to is the Okavango delta (which is amazing btw), but in terms of remoteness (lack of people/infrastructure) it's not that different from many of the surrounding areas

Except most of the "agriculture" damage occurs due to meat production: https://en.wikipedia.org/wiki/Environmental_impact_of_meat_p...

"In the contiguous United States, 127.4 million acres of crops are grown for animal consumption, compared to the 77.3 million acres of crops grown for human consumption.[23]"

Really? Please look at a map of europe and see how much wilderness you can find. Not a forest but actual real wild nature without humans or buildings. Almost anything you find is only there because it is useless for farming. I live outside cities but I have never in my life seen any wilderness outside television and pictures.

If you have a plot of land, why not make a few extra bucks?

You need logistics (electricity, roads, water). It costs a lot. It's more efficient to utilize 3D rather than utilizing only 2D.

When we're talking about humans, I'd agree that living in a crowded city is a terrible thing (though some people might like it). But when we're talking about industrial objects, efficiency is important.

If the space is available, it is nearly always cheaper and more efficient to build horizontally.

Exactly. Elon musk said something about the amount of solar required to power the entire country, and it was a very very small fraction of the land area. There is plenty of room for both plants and solar - separately.

Transportation of food is an issue, it also damages or controls food quality. Certain types of food (usually the tastiest varietals) don't transport well. Climate change may disrupt large portions of growing zones / home gardens in the next 5-50 years. Food in stores is grown & treated for how it will look on a shelf in a grocery store.. Not for nutritional value or taste.

Yep. Same problem that plagued "Solar FREAKIN' [sic] roadways" and is mentioned in the xkcd flowchart "Should I put Solar Panels on it?": https://xkcd.com/1924/

We have flat unused ground. Lets focus on getting solar there and put our whiz-bang technical chops to work solving the more difficult problem of robust distribution and storage of power.

Not just crops and power. I know a guy whose startup is using transparent solar panels in Germany on eco-friendly buildings with grass on roofs, to get power and eco-cooling, as well as Oxygen production - at least that is how he explained it. The concept is called green-roofs. Unfortunately I don't remember his startup's name.

A link with details about the concept, minus the use of transparent solar panels: https://buildingradar.com/construction-blog/green-roofs/

Are there places to read about this field ? journals, websites, discord anything ?

Do they grow enough grass to produce enough oxygen for the building?

The oxygen claim doesn't inspire confidence.

Plants don't produce any useful amount of oxygen, and real scientists know that.

A thing that they are good at however, is lowering temperatures in cities (compared to e.g. stone surfaces which store the warmth of the sun) – this alone might be a good reason to look into green roofs, given that we just passed the point of no return for Greenland's ice sheet recently.

It takes the same amount of energy to melt 1kg of 0°C ice into 0°C water as it takes to heat 1kg of 0°C water to 80°C.

You probably need to have a irrigation keep the plants alive. Probably spraying the concrete surface has the same effect.

You would have to spray the surface every day, plants need watering much less, close to never if they're native to the region.

>>> A thing that they are good at however, is lowering temperatures in cities

Plants are not magical, so if they get the same solar light influx then: (choose at least one)

a) They are actually not good keeping the temperature down?

b) The have more reflectivity, i.e. they are more white? (but I think they are darker)

c) The complex structure provides some air flow that keep the plant and soil cooler? (like the isolation of fur in animals, but in the other direction)

d) The specific heat of plants is greater than concrete? (plants have more water, and water has a big heat capacity)

e) The big heat capacity is due not to the water in the plant, but to the water in the soil?

f) The difference of temperature is caused by transpiration of the plant? (water has a huge heat of vaporization, plants try not to loos too much water in transpiration anyway)

g) Most of the evaporation is water that was in the soil?

For f) and g) two you need irrigation. Perhaps not daily because plants and soil are better storing water than concrete, but it is the same amount of water.

For d) and e), you need less irrigation, but perhaps it is better to have some kind of water tank of pipes, to avoid water lose.

For c) you can try with artificial grass. Does it work? Is it easier to maintain?

For b) it is probably better to use and aluminium foil cover (they are popular here it rooftop to avoid rain leaks)

I wonder how that compares to white painted or even reflective roofs?

The paint solutions don't require a gardener at least.

Usual white painted surfaces get hot too. And if you use some superhigh-reflectivity surface, you have to keep it clean.

So what on this earth is producing useful amounts of oxygen then?

Algae in the ocean, mostly.

But also, any growing plants - you could compute for every kg of dry plant matter, how much oxygen is released, as the dry plant matter is almost entirely carbon produced from breaking up CO2.

So unless you're collecting tens or hundreds of kilograms of dead plants from your roof every year, it isn't producing much oxygen.

This is why we won't solve climate change by simply planting trees. Planting trees is good but once the land is covered in trees like it was you can't go further. You have to start actively putting carbon underground so it doesn't end up in the air again.

Well, you can build shit with the wood that's going to last a long time and plant a new tree. Though I'm not sure the lumber processing & construction isn't producing more carbon than the tree sequesters...

And algae are plants last time I checked.

Because op said "Plants don't produce any useful amount of oxygen"

And I am aware, that room plants do not really add meaningful O2 to the room, their value is in humidifying.

Googling "are algae plants?", gives this as the first answer:

> Algae are in the plant kingdom, but technically they are not plants. ... Algae range in size from microscopic to meters long and from single-celled to complex organisms that rival large plants. These organisms may look like true plants, but unlike plants, algae do not have roots or true stems and leaves.

Either way, I wasn't thinking of algae or aware that they might be net oxygen producers for the atmosphere.

Big picture, oxygen isn't being either produced or consumed. The level is constant.

Individual oxygen atoms alternate between being in CO₂ molecules and O₂ molecules, as plants grab the carbon to build their bodies and return it after death.

But since the total mass of plant life doesn't change much, it all evens out.

Umm ... You may be confusing net production with actual production (ie plants produce pretty much all the O2 but they then reabsorb it)

I suspect it is also worth differentiating between production as has been going on for millions of years and industrial production - there is really no way to collect or harvest the oxygen made by plants - but that is kinda implied by the GP statement (that they wanted to cool the roof make electricity and Oxygen production (the implication being something useful to a business based on that roof)

So I can see your point.

https://en.m.wikipedia.org/wiki/Oxygen_cycle

>>Plants don't produce any useful amount of oxygen, and real scientists know that.

Could you please add some context to this statement. It is hard to believe that the oxygen produced by plants is so negligible as to be useless. Why?

Because plants use up oxygen when they decay, or when they’re digested by herbivores, and release CO2 in the process. Plants are carbon neutral for this reason.

Oxygen comes from algae in the ocean. The reason the ocean carbon cycle isn’t carbon neutral is because the carbon is fixed into calcium carbonate by zooplankton that feed on the algae. When these tiny animals die their calcium carbonate based exoskeletons sink and accumulate on the ocean floor, sequestering the carbon there.

Carbon sequestration used to take place on land as well (that’s where all fossil fuels originate) but now we have fungi and animals like beetles that can break down lignin and cellulose instead of allowing it to accumulate.

lmgfy

https://www.thoughtco.com/how-much-oxygen-does-one-tree-prod...

A fully mature tree produces anywhere from 2 to 10 persons-worth of oxygen.

I too am skeptical about the amount of oxygen that can be usefully produced by rooftop plants. Yet I still think it is a good idea.

"Dirt grass and a goat get you a LEED point - does the dirt grass and a goat make it work better? No! But you do feel better about yourself! Dirt is not insulation it's just freaking dirt"

- https://en.wikipedia.org/wiki/Joseph_Lstiburek (https://youtu.be/iHBYvqr2_io?t=2224)

Gotta love greenwashing. A real forward thinker would also start a second startup simultaneously to undo the damage green roofs will cause down the line to a building. :)

Edit: In case somebody misses the point the video from which the quote is sourced is well worth watching if you are curios about building science.

tl;dw - What is efficient and good for the environment is counterintuitive. Green roofs often cause more harm than good because reasons.

I don't really like having to watch some youtube video, to get the counterpoint, all presented in a non friendly way.

So do you have some facts, you want to share, why green roofs, a method for example used in scandinavia for a long time, is bad, if done right?

Because you quote ... is not a smart one. Because dirt is definitley insulation. And soild is more than dirt btw.

I didn't mean anything in an unfriendly way. The quote is not dumb but it needs a lot of context I suppose that might be missing.. definitely the key point is "if done right".

I can't really condense the video for you, the guy in it does throw in a bunch of jokes from the perspective of a frustrated Canadian building science guy that might put you off but his information is great.

My best attempt at a condensed parable: I once found myself driving around with a very environmentally minded person and she refused to turn the AC on in her car but cranked open the window instead.

> the guy in it does throw in a bunch of jokes from the perspective of a frustrated Canadian building science guy that might put you off but his information is great.

As someone else who works with civil (but not structural) engineering in Canada, I agree to a certain extent with his points, but found his tone incredibly condescending and offputting. For example:

> Does the dirt, grass, and a goat make it work better? No. But you just feel better about yourself. I mean dirt is not insulation, it's just freaking dirt. If it was insulation we'd put it in our walls, and that'd be stupid. [...] 'well we can store water up there' - Why? You're an idiot. The whole idea of a roof is to get the water off of the damn roof.

- Soil is insulating, just with a very crappy K value. You wouldn't use it somewhere that was space sensitive (eg a wall). You wouldn't use it instead of other insulation. But it is absolutely an insulator (that's why we only have to put frost walls 4-8feet deep to prevent frost heave). If your only goal is to insulate the roof better, install an extra inch of rigid foam rather than a foot of soil, it'll work the same.

- Storing water where it first strikes is good for reducing site runoff (with safeties installed to cope with bigger rainfall events).

> I once found myself driving around with a very environmentally minded person and she refused to turn the AC on in her car but cranked open the window instead.

How fast were you driving? There's a breakeven point, depends on the car - I know with mine, it's about 80 km/hr (slower than that, open the window. faster than that, AC is more fuel efficient)

You got the gist of what I was saying which is physics is at play and the answer is always "it depends". But people don't like that. Hence, AC off I'm a good person. Green roof I'm a good person. 'etc.

> I agree to a certain extent with his points, but found his tone incredibly condescending and offputting

That kind of says it all, doesn't it?

Personally I found it good natured tongue-firmly-in-cheek conspiratorial humour. Considering he is an actual authority on the subject and has seen a lot of incredibly idiotic behaviour and expensive and downright dangerous mistakes I think you can forgive him if his comedy schtick is not to your taste as long as the info is good.

This talk is even better: https://youtu.be/rkfAcWpOYAA

He seems like the grumpy Linus of the building science world and if he is a jerk he is my kind of jerk.

I'm also considering making a green roof. Apparently, since the plants (sedum/stonecrops and mosses) help cool the roof, the solar panels on top of it are a bit cooler too increasing their efficiency.

It also helps retain some water so it does not go to the sewer directly after it rains of the roof and keeps the sewer from getting overloaded.

Another claimed benefit it is that a green roof helps reduce fine particulates in the air. And biodiversity etc etc.

Its kinda expensive to do right though, so maybe some time.

Depending on the style of house, it also makes better use of space if you're otherwise trying to balance space for gardening or for your children to play, etc. I would love to be able to grow my vegetables on the roof and free up the ground level of a basketball ring or more lawn for the kids.

It's a bungalow so all ground level living (not just handy when you're old but apparently also when SO just delivered a baby) so the roof is also mostly flat.

I've considered adding a vegetable garden on the roof too, or maybe just herbs. And thought about a terrace on the roof too, that would be cool but the ground-level garden is nice already as it is.

So this technique reduces the sunlight the plants receive by about 57% but only reduces biomass growth by about 30%. It's very interesting. I imagine you could enclose the sides with glass or plastic and make a greenhouse from it. That makes me wonder if the reduction in growth wouldn't be offset by the ability to extend the growing season.

> I imagine you could enclose the sides with glass or plastic and make a greenhouse from it

FTA - that's why they tested on basil and spinach. Both crops are commonly grown in greenhouses

> make a greenhouse from it

That would be literally Earth-saving in some places. I know people who heat their greenhouses with wood! Wood, from forests, which are quickly dwindling, and yet it's cheaper than natural gas, so people use this country's forests to keep warm during winter just because it's cheaper.

From my point of view, that's absolutely insane and this country deserves what it gets.

Which is decreased rainfall, increased summer temperatures, landslides, floods (ironically) and crop damage so bad it puts farmers out of business (they're protesting right now).

Then they wonder "why, God, why?" like a bunch of headless chickens. We deserve everything we get. Sorry, I had to get this off my chest.

There's no shortage of open area to put solar panels. If we put a (nearly) continuous strip in every highway median, that would be a huge step forward, and still take up practically zero useable space. Even 1% of the federally owned land in the sun belt would generate an enormous amount of power.

This approach would benefit community solar and remote microgrid projects, as well as geographically constrained places like the UK where the study was done.

Just waiting for it to be economical in the nearer term and all of this stuff will magically start appearing. Everyone goes through the motions of thinking about solar solutions to energy, and then they realize how little power they provide and how many they need en masse and then scrap the idea.

Once the math adds up for a quicker ROI, the plans will stop getting shelved and will be presented as novel by different people.

I think we're already there for regular PV. It's getting to the point where a home system will almost pay for itself in less than 10 years.

I'm thinking 3 months would be ideal

Very few things have a return that quickly. In an era of 25 year mortgages, a 10 year payback is very reasonable.

Let's make these one of the few things that have a return that quickly.

That’s unlikely to ever happen; if it’s that cheap to produce electricity the utilities will have long since switched over and cut rates.

Ideal, I guess. Though I don't see how that could ever be possible.

"if the government were to take over the Sahara Desert, there would be a shortage of sand in five year" -- Milton Friedman (exaggerating, somewhat)

Better to put them on home roofs, and arrange for them to be owned by the homeowners, designed so that the occupants are (literally) empowered when the grid is mismanaged, as in California.

On highway medians control is more centralized, and they would require more maintenance and cleaning, which would be more disruptive in that location.

Solar panels on home roofs aren't necessarily configured to power the house without the grid. Also you would additionally need batteries and related hardware to have a usable source of power at any time, so unless your house is set up for off-grid solar, you still need the grid to be managed well.

Found this out in the house we are renting with solar panels installed by landlord. Bright sunny day, someone hits a pole nearby, power goes out.

There are two kinds of solar: one that adds to the existing signal from the mains, or one that is self-contained. The second kind is more complicated and therefore expensive. I wasn't aware of the distinction before, but I definitely am now.

Aren't there setups that can do both as well? i.e charge battery first and send excess to the grid?

Sure but they are more expensive. You need a rock solid controller with beefy and redundant electronics to make sure you're never going to be connected to the grid when you shouldn't be.

Yes, but any setup that's capable of feeding power back to the grid requires costly safety interlocks to allow linemen to make repairs at the street without your house unexpectedly energizing the line. Some jurisdictions just outright disallow it.

The setups have to be separate (e.g. different outlets for mains and solar) to protect the grid.

Even a small home solar installation puts out enough power to easily kill unsuspecting maintenance personell working on the grid, for example.

So the utility company has to have 100% control over he mains at all time for safety reasons (i.e. your meter must never run backwards). If they cut the power (e.g. for maintenance or repairs), no one must be able to feed power into the grid.

That's why even if you have a battery, said battery can either feed into the grid, or be connected to separate outlets in your house, but never both at the same time.

Meters run backward intentionally when selling solar back to the utility. You need a switching system that will isolate immediately if the grid fails, and resync with the grid AC before reconnecting, if you want to be able to operate on and off the grid.

That depends on the country then - in my country, you need to install a secondary meter instead.

> So the utility company has to have 100% control over he mains at all time for safety reasons

This is controlled independently by the solar inverters's software, not the utility via any sort of signal. That software is mandated by regulation as you say for the safety of line workers. Recent batteries allow for an "islanding" mode, which allows continued backup power delivery to the house during a grid outage but cuts off the grid connection.

> your meter must never run backwards

... during a grid outage. During normal operation it's fine for it to run backwards. That's what net metering quantifies.

> said battery can either feed into the grid, or be connected to separate outlets in your house, but never both at the same time.

I think this is a technical limitation, since it would require a current divider and 2 inverters, which is a level of complexity not worth it for the application.

> During normal operation it's fine for it to run backwards. That's what net metering quantifies.

Hm. Different countries, different regulations I guess. In my country you have to install a second meter instead.

That's not true, you can have an inverter setup which fails over to a battery backup when the grid goes down. It's also done all the time with natural gas generators.

The setup is more expensive, and it does have to meet certain requirements, but it is definitely an option.

True but, this has been made illegal in many places, California among them.

I don't actually know whether that's legislatively illegal, or simply banned by PG&E; but the effect is much the same.

Rooftop photovoltaic is currently more expensive, less efficient, and surprisingly dangerous to install. Solar thermal designs actually benefit from being on rooftops.

As to dust, economies of scale make a huge difference. It’s rarely worth it, but using a farm truck to spray water across miles of panels is much more efficient than tens of thousands of homeowners doing the same.

First I’ve heard of solar thermal. Any good links?

Goes back years. Simplest form is a squiggly pipe behind a pane of glass. Water runs slowly through the pipe and heats up.

Think rooftop solar water heaters.

What dangers are we talking about? Do solar panels add extra danger compared to just normal roof maintenance work?

To be clear their not that dangerous, but we are still talking extra deaths and accidents. Mostly from increased amount of time people spend on residential roofs. Roofing is about 30 deaths per 100,000 full time workers which is about double the average rate for construction.

Currently instillation is the primary, but not only risk. You also get electrical accidents and in rare cases fires. Plus an increased tendency for people to go onto a roof to check them out and or clean them etc. And some extra roof maintenance due to leaks from improper installation etc.

Personally, I don’t think it’s a major deal at the individual level. However, I thik it should be considered in terms of public policy.

It's also unattractive, which should matter to us.

Much of the distinctive beauty of traditional building in sunny areas comes from the roofs.

Solar tiling, which is still not a mature technology, doesn't add danger: we have to put something on a roof, and if installing solar tile takes extra time, it isn't by much. And it looks good.

Less efficient and more expensive? Sure. But as the meme would have it, it's free real estate. And since we're living through a grotesque failure of robustness on a civilizational scale, let me point out that it's more robust as well, particularly combined with on-site batteries.

Why do they count as unattractive? It seems that the "definition" of eyesore is wholey independent of aesthetics and entirely based upon if it is functional and new. Old windmills, steam engine trains, and canals are considered quaint, wind turbines, shipping canals and modern trains are considered "visual pollution". Modern art fixtures often deliberately defy all rules of structure and aesthetics and don't get tarred with this. I only have weird hypothesises as for why.

> unattractive

people used to say wind turbines are unattractive. Culture determines what's attractive, and it can be made to look nice.

I'm dubious about rooftop solar in suburban/urban areas. I think the gain is mostly from tax write offs and arbitrage. Compare hand installing solar panels on a roof with mechanized installation of a large scale solar array.

Just isn't going to compete with stuff like this.

https://www.youtube.com/watch?v=Xk21aAaJL_s

Generation of power at the point of consumption is nothing to sneeze at. It’s also efficient use of space. Taxes can work as incentivizing tool instead of or in addition to generating revenue for the government which is precisely what’s going on here.

> Better to put them on home roofs, and arrange for them to be owned by the homeowners, designed so that the occupants are (literally) empowered when the grid is mismanaged, as in California.

It turns out that the same California that you criticize now requires solar on newly built homes, just as you recommend, and much to the chagrin of people who feel like the state government is impinging on individuals' rights to build however they please.

> if the government were to take over the Sahara Desert, there would be a shortage of sand in five year" -- Milton Friedman (exaggerating, somewhat)

I know that this is meant to be a humorous comment, however, desert sand is not really usable for most things that we want sand for, for example, it is not suitable for concrete, since it is too fine. (https://petroleumservicecompany.com/blog/could-desert-sand-b...)

This is why, desire being in a desert, Dubai imports its sand! (https://www.bbc.com/worklife/article/20160502-even-desert-ci...)

It's most efficient to put the panels in a centralized location with high amounts of sunlight on mounts that track the sun. You get significantly higher yield because of the tracking and the location, and maintenance is cheaper because it's centralized.

The fact that you see far more home installations than farms means farms aren't economically viable, neither is home PV without subsidies, but people buy into the "empowerment" fantasy.

The balance of tracking mounts is not trivial.

They increase efficiency a lot (up to 40% for dual-axis trackers) but they also decrease ground a lot coverage, they increase cost of installation and cost of ownership, and they decrease availability.

It balances out to the positive.

See https://heliogen.com/

That's a heliostat system, not a solar panel system. Both involve the sun but they do so very differently.

It's also a company which wants to sell heliostats, they're not going to tell you it sucks.

Empowerment isn’t really a fantasy if there are rolling blackouts but your own power is still on. Sadly, not a hypothetical in California.

Im thinking just from a national security/redundancy/risk reduction standpoint it makes sense to move more generation closer to demand. There are lots of single points of failure in our power grid currently.

Edit: this is assuming the solar setup is designed to enable use when power is out; I assume homeowners who care about empowerment would make that investment, but you know what they say about assuming.

> Empowerment isn’t really a fantasy if there are rolling blackouts but your own power is still on. Sadly, not a hypothetical in California.

Seems easier to get a generator or a Power Wall, but either ends up being pretty expensive for handling the 2 hours of rolling blackouts for the first time in 20 years. There are also longer-term outages, maybe several hours every few years? And this is for people in population centers. Living in the mountains is a different story.

> Im thinking just from a national security/redundancy/risk reduction standpoint it makes sense to move more generation closer to demand

I'd rather put the money towards removing those single points of failure.

> Seems easier to get a generator or a Power Wall, but either ends up being pretty expensive for handling the 2 hours of rolling blackouts for the first time in 20 years.

The price of electricity changes over the day along with demand. I don't know by how much, but maybe if the Power Wall could be used in the high-cost hours and charged in the low-cost hours, it would make a difference?

Solar farms are in centralized locations. It is entirely possible that no farm has been constructed in that specific area.

> the occupants are (literally) empowered when the grid is mismanaged, as in California.

The California blackouts started around sunset, when solar dropped off the grid. Building more solar without an appropriate amount of storage just makes the problem worse.

Vehicles often crash into things beside a highway.

Planes sometimes fall on people's roofs. Let's not optimize for edge cases here?

This has to be the most ignorant comment ever posted on HN. In a typical year how many aircraft crash into structures? Zero. There are more than fifteen thousand car crashes in the USA every day.

The entire reason medians exist is because they are a crash safety device. Consideration for crashes is not an edge case, it’s the entire point of a median.

That will surely be taken into consideration from the start, and they will be designed in easily replaceable sections. If a car hits a section maybe it will be disabled but the rest of the cells will be fine and a crew will be dispatched to repair or replace the damaged cells.

Surely it is cheaper to simply place the panel somewhere else than it is to:

1. Pay for thousands of additional broken panels on a recurring basis

2. Pay people to replace thousands of broken panels

3. Shut down highways for utility work to replace thousands of broken panels

4. Design the panels to meet crash safety design considerations that the structures currently in the median were designed to

5. Add additional electrical safety standards unique to a panel array that designed to withstand car crashes.

Really, this is complete silliness.

They would also get dirty at a much faster rate because of all the dirt and soot generated by the vehicles going by.

The solar panels on roads idea has been tried. Rotting leaves were a big source of its failure.

https://www.businessinsider.com/first-solar-road-france-fail...

Doesn’t matter. Much of the US roads aren’t anywhere near trees - ie the southwest. Huge amount of roads and solar power potential there too. Also, cleaning crews are a thing that have existed in the past and should again.

Replace leaves with tumbleweeds. Or whatever natural debris we have in the west.

The leaves were causing damage to the solar panels. I imagine other types of debris would do the same.

But I'd be happy to be wrong. Have you asked why this hasn't already been done yet? Or if it has (besides the example I provided), what was the outcome?

Have you spent much time driving in the empty areas of the west? You can go 100 miles without even seeing a tumbleweed.

I've been living in the west my whole life and have traveled between Colorado to California through Nevada, Utah, Arizona, etc 7 or 8 times, so yes I've seen an empty western road before. Tumbleweeds was tongue in cheek but there's plenty of dirt, trash and other flying debris that will get baked onto a glassy surface out southwest.

Well, even in the Sahara there's sand and sandstorms piling it on solar panels...

There's no place that's 100% immune from all dirt/leaves/etc.

Still shouldn't be much of a problem in practice...

I think the key difference is whether the panel is placed at ground level (as in a solar road) or raised (as in most large-scale solar installations where the panels are raised on mounts that can also move and track the sun). The latter is pretty much self-cleaning when it comes to dry debris because the wind would eventually blow them away onto the ground (where the former will collect them forever).

I agree on both. It (degree fouling of the solar panels) is a fact of things, but shouldn't impact things much pragmatically.

I think that we can expect the same amount of accumulation of stuff as we currently get on these roads. Its not like we're out there street sweaping these rural highways, but they're also not covered in debris.

3/4 of Nevada is owned by the federal government and is dry to the point no one wants to be there anyway. Including planets. From your list, you probably haven’t seen the part of the Southwest which I was referring to earlier. As others have said, too, maintenance is going to be a thing for any form of energy.

In the southwest, I'd imagine dust would be the biggest hindrance.

It failed because building an efficient solar panel is already hard enough without thousands of cars running over them. Just build a solar-roof instead.

GP said the median, not the roadway itself.

One thing that I don't get about this and related stories: if the road surface is damaged as badly as they say, then why are there no pictures of the damage (the one picture showing damaged modules is described as not taken from modules instLled on the road)? Also, I googled several other stories and none of them has hard facts on why it failed, essentially speculating about different reasons.

Something about this story is not quite right, at least the way it was reported in English language media.

I can’t read the article, but previous articles I have read on the subject indicated that the road authorities who evaluated the tech never found it suitable to install on a public roadway to begin with. Besides the durability/maintenance issues, it also had lower friction than a normal road surface. I think one here in the US gave it a trial run as a sidewalk and even that use was a failure when the freeze and thaw cycle of the ground broke them.

Yeah, land is not at a shortage. The best land for solar is also worthless for other things, so it tends to be dirt cheap. There's enough unused space in the Southeast US to power the entire world off of solar. Obviously that wouldn't work for other reasons, but underscores nicely how land isn't the issue at all.

> If we put a (nearly) continuous strip in every highway median

Is there a shortage of land for solar?

I was wondering if they can be put up on poles holding train's electric tractive wires and then fed directly to the same wire. The issue i see is dc to ac conversion and lot of variability management.

Maintenance in the middle of the road sucks ...

I cannot imagine the revolution that solar power will produce if it can fall another 3-5x in the next 10 years. It is already at grid parity.

Although my personal hope is for storage, inverters, controllers and other technologies to get cheaper. Especially longer term storage beyond 4 hours.

I think it’s unlikely you see any fossil generation in the mix in 10 years except in the most remote of locations (with no solar or wind potential).

Wind and solar are already around 2 cents/kWh utility scale, and batteries are catching up. No fossil or nuclear generation can compete with that.

Source?

I don't disagree, would just like to share this information with friends :)

Commenting as a reminder to self to return with a model.

I'd bet there will be some natural gas generation in the US in non-remote areas in 2030. Maybe not new construction, but gas is cheap, responsive, and already in place. I don't think it'll be completely replaced by batteries and added renewable capacity that quickly, though I'd love to be proven wrong.

> Batteries are catching up.

Are they? The US consumes 11.5TWh of electricity daily. It's estimated that it needs 3 weeks if storage to get to 100% carbon free [1]. By comparison global battery production in 2019 was 300GWh [2]. Even if you factor in the fact that the curve of battery production is rising, it'd take decades to fullfil just the US's storage demands with batteries. There are other storage options like hydroelectricity and pumping air into mineshafts, but those are geographically limited.

1. https://pv-magazine-usa.com/2018/03/01/12-hours-energy-stora...

2. https://cleantechnica.com/2019/04/14/global-lithium-ion-batt...

They are [1]. It’s a self reinforcing cycle. For example, batteries are already cheaper than most gas peakers. That demand (along with EVs demand, primarily Tesla) ramps manufacturing capacity, realizing further cost declines along the way.

Remember, the sun and wind are free once the turbines and panels are installed (both which last at least two decades). That’s what fossil and nuclear are competing against, and it’s a losing battle. Sounds like those companies that sell batteries to utilities and consumers are in a very favorable position, considering the storage requirements you note.

[1] https://about.bnef.com/blog/battery-pack-prices-fall-as-mark...

Yes, the capacity is increasing. But there's still a massive disconnect between the amount of battery storage required to make renewables usable and the capacity that exists. The link I posted already factors in increasing demand, but the amount of battery production in these projections is still orders of magnitude lower than what is requires.

3 weeks of energy storage in the US works out to 240 TWh given its daily 11.5 TWh consumption. Even if we assume that the projections are accurate and that global battery production will reach 1 TWh in 2023 and 2 TWh per year in 2030, we're still talking about several decades worth of global battery production just to supply the United States' storage requirements. Even just reaching the 12 hours of storage required to reach 80% renewables is going to be difficult to achieve.

The reality is that storage even remotely close to what is necessary to run a country predominantly on intermittent sources has never been built. This is totally uncharted territory as far as energy infrastructure goes. And none of our current solutions are capable of delivering the required scale, save for geographically limited options like hydroelectricity. By comparison, multiple countries generate the majority of their electricity from nuclear power, and one has generated over 80% of its energy from nuclear. Between building a wholly novel solution and simply replicating an existing solution, the latter is almost always the easier task.

This thread is being rate limited, reply in edit:

> 1. Instantaneous excess can electrolyse water, producing hydrogen which can be converted into methane and stored/used in existing natural gas systems.

This is much more difficult to do than it sounds. In order to convert hydrogen into methane you need a source of carbon. The fraction of a percent of carbon that exists in the atmosphere cannot feasibly be used. The plans to use synthetic methane as energy storage are contingent on somehow capturing the carbon from burning a gas turbine. California tried to do this by pumping the exhaust into mine shaft, but a leak was sprung and the gas escaped. Not to mention, places without mineshafts nearby have to construct structures to store the exhaust.

> 2. Overcapacity in good times implies proportionally higher production in bad times, lowering the storage requirements.

No it does not. Overcapacity of solar doesn't make the sun shine at night. Overcapacity of wind somewhat increases production in less windy days, but a totally windless day still generates zero energy regardless of overcapacity.

What feels like an obvious solution (and is therefore probably wrong), is that excess renewable production can mitigate that in two ways:

1. Instantaneous excess can electrolyse water, producing hydrogen which can be converted into methane and stored/used in existing natural gas systems.

2. Overcapacity in good times implies proportionally higher production in bad times, lowering the storage requirements.

Or stacking blocks

https://qz.com/1355672/stacking-concrete-blocks-is-a-surpris...

Apparently each of these structures stores 20 MWh of energy. By comparison, the US consumes 11.5 TWh of electricity daily. To reach the 12 hours of storage estimated to be necessary to reach 80% renewable generation we'd need 287,500 of these towers. To reach the 3 weeks of storage necessary for 100% renewable generation we'd need 12,075,000 of these towers.

The former is easily achievable, if the towers are profitable to install. We only have to build them one at a time, and if a collection of 10-50 is cheaper than a peaker gas plant, then the utility decommissions the latter and builds the former.

The latter is simply not necessary. There are a number of ways to solve the last few percent, including leaving a few peaker plants running; presumably, we'll do all of them.

Those peakers can be carbon-neutral, because it's possible to run CO2 extractors. One implication of our renewables is that there are times when they generate power considerably in excess of requirements: using that energy to sequester carbon is plausible.

Of course, if we got over our civilizational horror of nuclear energy, we could solve this problem in a thorough and boring way. I'm not holding my breath.

Thorium reactors or pebble bed reactors might be options. The only reason we have the current designs is due to the us navies need to build a reactor that would fit on submarines and ships. That technology became the basis for our deployed reactors. Since then nothing else has been tried outside of small experimental plants from what I understand.

This is getting tiring... No, nobody is insane enough to only use batteries. They are primarily used to load-shift by a few hours within a 24 hour window. This is mostly useful for PV because it has a very low window during which it generates energy. Longer term storage would simply involve power to gas infrastructure. Alternatively you can use natural gas as your storage mechanism until power to gas has been implemented.

A lot of complaints against renewables are rooted in the myth of "baseload". For renewables to be effective they have to be available 24/7 except this is completely wrong. The atmosphere doesn't care if you pollute at 3 am or at 3 pm. A kilogram of CO2 is a kilogram of CO2. All you have to look at is how much renewable energy has been produced per year and divide it by total energy produced per year to calculate the renewable share. As long as that number goes up you're reducing CO2 emissions. Of course at some point you hit a roadblock where that share ceases to go up because you need to store energy but no country on earth has reached that point.

Here is an in-depth article that explains how 100% renewables could be implemented: https://cleantechnica.com/2020/02/09/correcting-anti-renewab...

Existing energy storage options other than batteries are either geographically limited, or not feasible. I explain the issues with natural gas storage in another comment: https://news.ycombinator.com/item?id=24253317 You can't just produce natural gas out of hydrogen and air, you need a source of carbon (and the fraction of a percent of the carbon in the atmosphere cannot feasibly be used).

Yes, solar and wind can mitigate fossil fuel use in the short term. But there is no feasible way to use them for the primary source of energy without massive amounts of storage. It provides an option to produce some carbon-free energy, but does not provide an option to go from "some" to "all". If we actually want to stop climate change, we need to go for "all". The link you posted does not refute this. The solution proposed in the article is to just use fossil fuel backup plants until a storage solution is found.

Germany and California are both already approaching the saturation point for daytime generation. And once you hit that point there's no way to keep going without massive amounts of storage to transfer the excess generation during peak hours to non-producing hours. Intermittent sources cheaply reduce carbon emissions in the short term, but offer no path to fully renewable energy without a miraculous advancement in energy storage. The paper you linked to doesn't refute this. The plan laid out amounts to, "keep burning fossil fuels and hope we eventually figure out energy storage". When the fate of the world is at stake do you want to bet on an unknown and unproven solution, or a solution that has successfully delivered the lion's share of a nation's power since the 1980s?

The full paper from citation 1 is available here:

"Geophysical constraints on the reliability of solar and wind power in the United States"

https://escholarship.org/content/qt96315051/qt96315051.pdf

If you look at Figure 2, they model different combinations of overproduction, storage, and regional aggregation (interconnection). Overproduction helps significantly. At 50% (1.5x) overproduction, the United States can supply 75% of demand with no storage and little new interconnection. At 1.5x overproduction with 12 hours of storage, it can supply 95% of demand with even less interconnection.

If the AP1000 units under construction at Plant Vogtle do not go over budget any further, they will have cost $11.20 per watt to construct [1] -- $25 billion spread over 2234 MW of generating capacity. If they have a capacity factor of 93%, that's $12.04 per watt of annualized output.

Utility scale solar in the United States achieves an average capacity factor of 25% as of 2018 [2] and had a median construction cost of $1.60 per watt as of 2018 [3], with costs still falling. That's $6.40 per watt of annualized output, or $9.60 with 1.5x overproduction.

Wind costs are similar. Wind has higher up front construction costs but also higher capacity factors in favorable regions.

Once constructed, solar and wind also have lower operation and maintenance costs per MWh generated than nuclear plants do.

I was very enthusiastic about nuclear power from about 2000-2015. I still think that it's safe enough and far cleaner than fossil power. We shouldn't shut any operating reactors down prematurely. But large scale renewable projects have cut costs drastically since the turn of the millennium while new nuclear projects keep going late and over budget. The EPR and AP1000 reactors were supposed to be the standardized, affordable, predictable reactors that retired the nuclear industry's history of cost overruns and schedule blowouts. Instead they have become spectacular contemporary examples of those same old problems.

[1] "Vogtle Cost Upgrade Causes Rethinking of $25B Nuclear Plant’s Future" https://www.power-eng.com/2018/08/09/vogtle-cost-upgrade-cau...

[2] "Capacity Factors for Utility Scale Generators Primarily Using Non-Fossil Fuels" https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...

[3] "Utility Scale Solar: Empirical Trends in Project Technology, Cost, Performance, and PPA Pricing in the United States - 2019 Edition" https://emp.lbl.gov/sites/default/files/lbnl_utility_scale_s...

By comparison, a plant of the same design as the Vogtle plant was built in China at a cost of $7.3B, yielding a cost of $3.17 per watt of output [1] - under 1/3rd of the solar cost with the required overproduction. The Vogtle plant is the first of its kind in the United States. First of a kind plants typically cost about twice as much as subsequent designs.

Furthermore, you're not including the cost of storage for your estimates on solar and wind. Even 12 hours of storage represents a staggering amount of storage - that's 5.75 TWh given the US's average daily 11.5 TWh consumption. Costs per KWh are still on the order of hundreds of dollars per KWh. At $200/KWh 5.75 TWh works out to over a trillion dollars. And this is a recurring cost, as storage needs to be replaced. Hydroelectric storage is cheaper and doesn't need to be replaced, but is geographically limited. Even then, it's not that much cheaper at $100-160/KWh [2]

Yes, renewables work if energy storage becomes effectively free. But energy storage is anything but free.

1. https://en.wikipedia.org/wiki/Sanmen_Nuclear_Power_Station

2. https://www.renewableenergyworld.com/2019/08/08/report-cover....

The paper you cited shows that 1.5x overproduction can get the US to 75% of electricity from solar and wind without building any storage.

Every big construction project is cheaper in China than in the US. China can build a solar farm for $0.83/watt [1], half the cost I cited up-thread for an American solar farm. But I don't think that $0.83/watt is a credible construction cost for a solar farm in the US in 2020. Nor is $3.17/watt a credible cost for constructing a nuclear plant in the US in 2020.

I am weary of hearing about how the next reactor design is going to be affordable and take only 5 years to build. That's what I heard from Westinghouse and Areva/EDF when the AP1000 and EPR were still theoretical reactors. I believed it for a while. I don't believe it any more in 2020. I don't believe it about molten salt reactors, traveling wave reactors, or whatever theoretical reactor is currently cherished by Ted Talkers. I'm willing to start believing it again after a reactor design has entered commercial operation in the United States or European Union and lived up to its claims.

I don't want to write off nuclear power entirely. It's much safer than fossil power, both in terms of acute human health risks and climate risks. I still couldn't advise any American utility that new nuclear plants are a fiscally prudent part of decarbonization planning for the next decade.

[1] https://www.bloomberg.com/news/articles/2019-12-26/china-s-b...

> The paper you cited shows that 1.5x overproduction can get the US to 75% of electricity from solar and wind without building any storage.

Right, without storage you have to scale back the percentage of electricity you get from intermittent sources. Like I said, without storage, renewables do not present a valid option for a carbon free source of energy.

I you want a US example of a nuclear plant construction, you can take the Diablo Canyon plant [1]. This is not only built in the US recently, but also in an earthquake prone area and thus needed more robust construction. It cost 13.8 billion in 2018 dollars. Plants constructed earlier are even more cost effective, even when adjusted for inflation. The Donald Cook plant [2] produces about as much as the AP1000 plant, for only 3.35 billion 2007 dollars. That's about 4.25 billion in 2020 dollars. And this isn't an anomaly. Plenty of plants built during the 70s were similarly cost effective [3] [4] You're picking an individual plant to inflate the cost of nuclear dramatically.

You're absolutely right that the next reactor design isn't going to be affordable. First of a kind production is always the most expensive. Nuclear power gets cheaper with repeated constructions of the same design. You don't need to re-build the manufacturing pipeline to make components, staff become experienced in construction, and other benefits.

This is why France's nuclear program was one of the most successful. They standardized on 3 designs, and built serial production of those same 3 designs. The APR is expensive precisely because it's one of the first large plants that France has built in decades, and they don't have that advantage of serial production.

This is also why nuclear plants built during the 1970s in the US are much more cost effective than the ones built today. The US was building a lot of nuclear plants, and so it benefited from this economy of scale.

1. https://en.wikipedia.org/wiki/Diablo_Canyon_Power_Plant

2. https://en.wikipedia.org/wiki/Donald_C._Cook_Nuclear_Plant

3. https://en.wikipedia.org/wiki/Byron_Nuclear_Generating_Stati...

4. https://en.wikipedia.org/wiki/Braidwood_Nuclear_Generating_S...

75% of all electricity consumption is too low to be a "valid option" for decarbonizing electricity? We have different ideas of what's valid.

If you want a US example of a nuclear plant construction, you can take the Diablo Canyon plant [1]. This is not only built in the US recently, but also in an earthquake prone area and thus needed more robust construction. It cost 13.8 billion in 2018 dollars. ... You're picking an individual plant to inflate the cost of nuclear dramatically.

Diablo Canyon unit 1 construction began in 1968 and unit 2 in 1970 according to the page you linked. That's hardly recent. I was actually trying to be charitable to American nuclear by talking about the new Vogtle units without mentioning the billions spent at V.C. Summer on two incomplete AP1000 reactors that will not enter service at all.

I agree that 1970s era nuclear plants cost less. Part of that was that there was more experience with building them, so the average was lower. Another reason is that when we look at nuclear plants running today and tabulate cost by year of construction, we're cherry picking the projects that went well.

I count 41 American reactors that were cancelled while under construction on this page:

https://en.wikipedia.org/wiki/List_of_cancelled_nuclear_reac...

37 of them started construction in the 1970s. That's a high project failure rate compared to any other generation source.

> 75% of all electricity consumption is too low to be a "valid option" for decarbonizing electricity? We have different ideas of what's valid.

The US already generates ~40% of its electricity from carbon free sources. An increase to 75% represents only about a 60% reduction in fossil fuels from the current status quo. This is absolutely not a solution. We're still advancing climate change. Halving the time it takes to reach a disaster is not even remotely close to the same thing as averting a disaster.

> 37 of them started construction in the 1970s. That's a high project failure rate compared to any other generation source

Yes, because of Three Mile Island. Most of the cancellations were for reactors that started in the 1970s, because the US mostly stopped constructing reactors in the 1970s. You don't have cancellations for projects that began in the 1960s because those projects finished before Three Mile Island. You don't have project cancellations in the 1980s and 1990s because the US largely stopped starting new nuclear projects.

This pattern of cancellations demonstrates the fact that the high failure rate is due to political pressure, not economic unsuitability of nuclear reactors. Serialized production yields costs per kilowatt hour well below your estimates for renewables even without the cost of storage.

And no, if we look at reactors that are no longer in operation we don't see a much higher cost [1] [2] [3] [4] [5].

Serialized nuclear construction is by far the cheapest and most effective way to eliminate carbon emissions from electricity generation. Intermittent sources are cheap until they reach saturation during their time of production. Then costs skyrocket when storage becomes necessary. And even more importantly, nuclear is the only proven way of accomplishing this.

1. https://en.wikipedia.org/wiki/Rancho_Seco_Nuclear_Generating...

2. https://en.wikipedia.org/wiki/Big_Rock_Point_Nuclear_Power_P...

3. https://en.wikipedia.org/wiki/Crystal_River_Nuclear_Plant

4. https://en.wikipedia.org/wiki/Kewaunee_Power_Station

5. https://en.wikipedia.org/wiki/Oyster_Creek_Nuclear_Generatin...

The 75% figure is from solar and wind alone. The balance can come from any combination of nuclear, other renewables, and fossil fuels. It doesn't mean 25% electricity supplied by fossil fuels.

You consider France's electricity sector a decarbonization success story, right? It generates "only" 72% of electricity from nuclear power: https://en.wikipedia.org/wiki/Electricity_sector_in_France

The United States also gets 7% of its electricity from hydro and geothermal:

https://www.eia.gov/tools/faqs/faq.php?id=427&t=3

Plus 19.7% from existing American reactors, though that number is going to drift downward as retirements continue to outpace construction.

I think that the residual fossil demand would be significantly less than 25%. I can't say how much exactly. That needs another study. In the absence of storage, neither nuclear nor geothermal plants are good at supplying peak demands. Hydro can serve a peaking role to some extent even without building new pumped storage but it's constrained by reservoir volumes, minimum downstream flow rates, seasonal snow melt, etc.

> In the absence of storage, neither nuclear nor geothermal plants are good at supplying peak demands.

This is false. Nuclear and geothermal power can both satisfy peak demand just fine. Nuclear plants do take time to alter the thermal output of the reactor, but they can easily reduce the electric output through overcooling. Same MWt, but lower MWe. Geothermal plants just pump less water into the borehole. Better yet, nuclear plants can direct the excess energy to things like desalination. This is much easier than trying to satisfy peak demand with solar or wind, where peak demand often occurs when the sun isn't visible or when wind speed is substantially higher or lower than demand.

Again, France at its peak generated over 85% of it's electricity from nuclear power. I'm not sure where you're getting this myth that nuclear plants can't satisfy variable demand.

Nuclear plants can throttle down. But the economics of nuclear power make it prohibitive to satisfy peak demand from nuclear reactors. Even France relies on gas plants and power imports to satisfy its electricity demand peaks, despite being a net electricity exporter over the course of a full year.

The CAISO grid had an average power demand of 25 GW in 2019 but a peak demand of 46 GW (Table 1.1):

http://www.caiso.com/Documents/2019AnnualReportonMarketIssue...

Keeping enough nuclear reactors operating to supply the most demanding hours of the most demanding season would have extraordinarily high marginal costs for the last few terawatt hours.

This is true not because of any shortcomings of nuclear, but by virtue of the fact that demand is not uniform. The same need to have excess capacity during non peak hours in order to have sufficient capacity during peak hours exists with fossil fuels. If peak demand is 130 GW and trough demand is 100GW you need 130 GW of capacity.

Nuclear has never been inexpensive enough to be the first choice for meeting peak demand in the absence of storage. Some pumped hydro plants were built in the 20th century to be charged by nuclear generation so nuclear could effectively supply peaks too. Peaking batteries could also be charged by nuclear power.

Gas turbines have a construction cost under $1/watt in the US while Vogtle's AP1000s were estimated at $6/watt even before all the cost overruns started. If you're going to leave an asset idle most of the time, much better to idle a sub-$1/watt asset than a $6/watt asset.

This is just factually wrong. France had generated the majority of it's electricity from nuclear since the 80s, and Belgium now generates the majority of it's power from nuclear. Nuclear had repeatedly been used to satisfy peak demand.

Nobody doubts that fossil fuels are cheaper. Yes, that's why fossil fuels are still in widespread use outside of France, and several countries with lots of hydroelectric power. But if we want to halt climate change we need to eliminate - not just reduce - usage of fossil fuels. Any plan to use renewables as a significant source of energy either involves the continued use of fossil fuels, or the involvement of staggering amounts of energy storage.

Per the beginning of this long thread, wind and solar can supply 75% of annual US electrical demand without storage. France supplies about that much of its annual demand from nuclear power and Belgium supplies a bit over half of annual demand with nuclear power. Both countries rely on fossil generated electricity for meeting demand peaks, both via domestic generating plants and cross-border imports from foreign fossil plants. There was never a year when France met its peak electrical demand without fossil power.

The example of France proves that electrical generation could have been largely decarbonized in the 20th century, if other leaders had made a concerted push to reduce fossil fuel dependency like France's leaders did. It's tragic that other major economies did not do the same. But even France did not eliminate all fossil generation. 10% of French electricity generation is fossil as of 2017 [1].

Getting the USA's electrical generation down to only 10% fossil would be a vast improvement. I don't think that a contemporary optimized plan for getting there involves much new nuclear power even though a 20th century plan would have. A cost optimized plan from 1985 certainly would have called for a lot more nuclear power. The costs of building American solar and wind farms have plummeted since 1985. The costs of building American nuclear plants have not.

[1] https://www.world-nuclear.org/information-library/country-pr...

France's peak energy consumption is more than 40% higher than it's trough energy demand [1]. Most years France generates ~10% of its energy from fossil fuels. Nuclear was indeed used to supply a substantial part of the peak energy demand. The substantial majority of its peak demand was fulfilled with nuclear energy. France's share of fossil fuels actually used to be lower than 10%. France's more recent uptick in fossil fuels accompanied by a drop in the share of nuclear power generation [2]. Renewable energy production increased, but its intermittency leads to an increase in fossil fuel consumption. A real world example of how the shortcomings of renewables as compared to nuclear power results in more carbon emissions.

As per your own comments, solar and wind even with substantial overproduction leave a quarter of electricity demand unfulfilled. The places that are fortunate to have hydroelectric or geothermal power available could go carbon free, but the rest are left supplying a quarter of energy with fossil fuels. The overproduction puts their price well above the cost of nuclear when you don't cherry pick one of the most infamous cost overruns as a representative example. And let's just be generous and ignore the ecological devastation caused by covering 2-4% of the Earth's land surface in solar panels.

So we have a more expensive option that leaves a quarter of electricity demand to be fulfilled by other sources (mostly fossil fuels), requires massive amounts of land to be cleared and covered in solar panels, and is subject the challenges of intermittent power generation. And we have nuclear, which is cheaper, much less land intensive, and generates consistent energy. The superior choice is unambiguous. And real world examples demonstrate this. Look at the disparity between France and Germany. The former is the posterchild of nuclear, the latter the posterchild of renewables. France's carbon intensity of electricity is usually more than a factor of 4 times smaller than Germany's. We've already put nuclear and renewables to the test. And nuclear proves to be far superior.

1. https://www.services-rte.com/en/view-data-published-by-rte/d...

2. https://en.wikipedia.org/wiki/Electricity_sector_in_France#/...

I'll be interested again when France builds new reactors cheaper than new renewables. Flamanville 3 and Olkiluoto 3, even if they don't have further cost overruns, are going to produce electricity at a higher cost per MWh than German solar farms completed in the same year.

If France does build 6 more EPRs, a proposal floated last year, they will have a chance to prove that the problems to date were merely FOAK learning experiences.

France doesn't need to build new reactors largely because it's existing reactor fleet is still enough to fulfill demand. That's one of the biggest advantages of nuclear power, it lasts for the better part of a century not a decade or two. A serial run if reactor production makes more sense once the disparity between supply and demand is greater.

I'll be interested in renewables once Germany's carbon intensity per Watt is on the same order of magnitude as France. They need to drop from ~500 grams per Watt to under a hundred.

Which means we need battery storage at LCOE < 3 cents/kwh so a battery that lasts many cycles (> 4000) would really help in lowering costs.

When I spin thinking I see:

- information is mostly everywhere

- computing is mostly everywhere, can turn knowledge into instructions

- most machinery is accessible and can be replicated (not saying cpu fab)

- what's missing in that frame is an open faucet of clean energy

Instead of inverters, there should be a push for DC network.

Virtually all SMPS would be able to to work with DC (right now) and they won't even need active power factor correction either. Washing mashines with brushless DC motors, most ovens would be fine too. When I think almost everything that I have home, save for geothermal pump and three-phase appliances would be ok powered by DC(0). DC has its own issues: galvanic corrosion possibly being one, arcs too (no self-extinguish 50/60 times sec) but it has no issues with inductance, hence lower transport costs.

(0)Cheap LEDs with capacitor dropper or regulation by triacs are not compatible.

I see DC used in electric cars, general automotive and RVs.

I will say 12v is not very useful, except maybe for LED lighting. It has high losses to travel any distance. To power anything of significance requires higher voltage (or enormous cables).

I do agree that it would be really good to use DC, but I kind of wonder what the reality of efficient and useful DC would be like.

12v DC is not even useful for LEDs as it requires current limiting resistors - hence power wasted to heat. The proper (efficient) way to drive LEDs is via constant current source.

I meant DC as in 230-330V DC for home/office use. I meant generally replace AC (high voltage) lines with DC ones.

This is very interesting!

A few related questions come to mind:

1) What happens when two or more semi-transparent solar panels are stacked one behind the other? Is output power then comparable to the highest efficiency solar panel, do you get more, do you get less, and if so, how much less?

2) Polarization of light and solar panels -- what happens if light is polarized by a filter before going to a solar panel? And then, what happens (in terms of overall energy production) when that polarization filter is turned to an angle? And then the same question, applied to both regular solar panels, and these semi-transparent solar panels.

3) While I'm on the topic, has any researcher out there found a way to get even so much as a single millivolt/milliwatt (microvolt/microwatt?) from solar power coupled with a fully transparent surface, like let's say, glass, or some other crystal? I seem to recall some researcher somewhere that showed that very small charge regions occur at boundaries when sunlight hits plain transparent water -- but I do not recall the details...

Our area of Oregon recently banned new solar farms on the grounds that it detracts from the beauty of the landscape – a wine region with lots of tourism. Ironically, that very beauty is threatened by the changing climate, which clean energy could help mitigate.

eh i don’t see anything wrong with this. some areas are beautiful and should remain that way. we have a ton of space in oregon and the us. tons of space that no one is ever going to care about. i think it’s ok for people to protect places that have interest and economic benefits

I’m not saying there’s anything wrong with trying to protect the character of the region. In fact, the beauty is something that — hopefully — makes visitors appreciate the environment.

But when you look at what’s already allowed in farm-use zones, there’s plenty of eye-sore potential. So, my issue is with painting with too wide a brush (and unfairly singling out a use that’s arguably important to preserving the environment over the longer term). They should have the ability to look case-by-case.

If someone has an area on their property that’s shielded from public view, why not let them use it for a solar array? Studies have shown that, properly configured, solar arrays can actually improve prairie soils. And like the large array in Hawaii, grazers like sheep can be incorporated into the design.

Just seems bonkers to me to outright ban the solar arrays.

Let's be real for a second. Climate change isn't going to destroy Oregon's wine-growing regions within our lifetimes. A solar farm will change it within months. You can support or oppose solar farm bans according to your liking, but you should do so on the basis of facts. The two forces aren't even close to equal in magnitude and timing.

The “not within my lifetime so who cares” trope has been around for decades, and guess what? Climate change is happening faster than anyone imagined, mostly because scientists can only present findings on things they are certain about, which makes the predictions conservative. Most people are already seeing the impact of climate change, and if it’s not visible to you personally, it has never been easier to seek out information on those that are. If you really can’t see past your own lifetime and feel that you should be able to take whatever you want from the planet simply because you don’t need to deal with the repercussions, then you are not part of human society and are free to leave the planet at any time.

No matter how you try to write it politely, "I don't agree with your position, kill yourself" is a shitty comment.

It's already partially responsible [1] for negatively impacting Northern California's wine growing and this year could be worse.

1. https://www.nationalgeographic.com/science/2019/10/climate-c...

> isn't going to destroy Oregon's wine-growing regions within our lifetimes

Shameless.

I suppose I must be different than you, in that I love my children

Is that supposed a joke? Solar panels are just blue squares. Other than aesthetics they do practically nothing to hurt Oregon.

Solar is going to ruin Oregon's Wine-growing region in months? Because people don't like to look at them?

Absurd.

Could we design one to mostly get energy from green light which plants reject anyway?

This was my first thought, but PV panels that capture 25% (I'm guessing) the energy of standard panels are only viable if the cost of land is the limiting factor.

The other complicating factor is that large-scale farming requires a decent amount of horizontal and vertical clearance, so the structure for the panels would be substantial, especially if you want to track the sun.

From the abstract:

>selective utilization of different light wavelengths

Yes, it says it in the abstract, but isn't really given special attention to in the article itself.

Looking at the graphic it looks like a fairly normal absorption spectrum for a solar panel without it being specifically tailored to this use-case. It seems like there might still be something won by specifically tailoring it to be complementary to the plant absorption spectrum. On the other hand it might also not be economically viable due to lack of scale and varying requirements for wavelengths between plant species and stages of plant development, which makes some optimizations moot.

There is a LOT of low-hanging fruit when it comes to where to install plain old regular solar.

We could probably spend the next 50-100 years installing as many (regular) solar panels as possible and still have plenty of places left to put more of them.

Obviously it's not bad to develop these technologies, but I think they'll only be useful in niche applications.

I'm imagining a green-greenhouse which covers all of it's energy usage with these panels.

Edit: heck, what about auto-glass?

This is fascinating but you have to wonder how it would work with current harvesting techniques. New harvesting machines would have to be invented to work around the support infrastructure for the panels if they were to be deployed at scale.

"Maximizing the generation of electricity is a desirable goal, but might be at the expense of biomass production. For example, for lettuce, the total biomass yield under agrivoltaic installation in Montpellier (France) was 15–30% less than the control conditions (i.e., full‐sun conditions).[28, 29] When growth of tomato was tested in Japan, the yield in an agrivoltaic regime was about 10% lower than for conventional agriculture."

I always wondered why you could not just place the panels a bit higher. So that the sun can pass on certain times etc.

Yeah, people are treating this solar panel like a hammer and finding any use-case that looks like a nail.

Instead of a entire roof of panels that pass 50% of the light, it’s is more simple to make a roof of half covered in panels that pass 0% of light... like a pergola.

Alternatively, dust build up on the solar panels can prevent production of both.

automated panel cleaning is probably solved by now

Besides: nuclear power plants take up very little space. I really can't seriously people pushing solar, wind, and so on while they eschew nuclear power (and increasingly hydropower too).

Fake environmentalists: "We have an existential crisis! We must change our energy strategy to save humanity!"

Engineers: "That's quite a problem. Here's a way to solve it. It's called fission. Here are some power plant designs."

Fake environmentalists: "Nooo! Not that plan! This existential problem can be solved using only those technologies that agree with my aesthetics!"

It gets old after a while. If carbon-induced anthropogenic climate is a problem --- and I think it is --- then we shouldn't disparage good solutions on weak grounds in favor of solutions with serious problems. We don't need to devote swaths of land to solar and wind if we just build nice compact nuclear power stations.

> only those technologies that agree with my aesthetics!"

This is an exceptionally bad straw-man [1].

1. https://en.wikipedia.org/wiki/Nuclear_power_debate

So you think caring about nuclear waste along with CO2 emissions makes someone a fake environmentalist? Nuclear waste is highly toxic and difficult to store and transport safely.

Also, have you ever heard of Chernobyl or Fukushima? Nuclear reactors are great in certain ways, but can be catastrophically bad too.

Hydro also can cause a significant environmental impact, flooding natural habitat and interrupting water routes for different animals.

Solar and wind aren’t perfect either, but the idea is to try to chose a power source that is as clean as possible.

The tone of your post (being simultaneously dismissive and insulting to those who have a different view than you) is very trollish. The problem many people have with nuclear power are things like accidents making areas uninhabitable, radiation making people sick, disposal of waste rods is difficult, some materials can be used to make weapons, and the cost to make a safe plant are staggering and leading to cancellation of projects.

Renewable sources don’t have these downsides. Are they ugly? Not any uglier than a concrete dome and cooling systems of a nuclear power plant. You can bet wine country does not want a nuclear plant in their valley either. I think it’s perfectly reasonable to zone land usage appropriately.

Renewables have externalities too. Just because it's harder to mass hyterise them, they still exist. Eg the cost of mining for battery parts, parts that are needed to manufacture hundreds of thousands of wind turbines, millions of PV panels, inverters, etc.

That said, of course it's perfectly reasonable to try to preserve some areas, and to put power generation somewhere out of sight.

Agree.

Compared to renewables - nuclear is a big risk (financial and operational). Also nuclear needs a lot of water, which is getting to be a serious problem. Compared to coal/gas/biomass they look great though in our current terraforming predicament.

There is no way we could build enough of them in the near term to matter, so that makes this discussion moot anyway. There is simply not enough expertise and production capacity left. Very few nuclear plants have been completed recently and the institutional knowlege is fading. It takes a lot of time and effort to reinvigorate that, especially since the nuclear industry is so extremely conservative.

Also the conversation is not being done on technical merits - but political inertia, an unwillingness to change and special interests by established energy companies (coal, gas).

As you say, renewables are still winning (slowly) because of the low risk profile and generally being price competitive.

Not that it matters much, we are mostly over the point of no return. It's just a matter of time before this ball is getting very unpleasant, sadly. We are just playing with the dial on how quickly that happens.

New nuclear power plant designs [1] have many intrinsic safety features that largely obviate the old safety concerns that you mention. Anti-nuclear advocates conspicuously ignore these new designs, instead opposing a vision of the nuclear power system that hasn't been current since the 1960s. Argumentum ad Chernobylum just convinces me that the animus against nuclear power comes from aesthetic considerations and not a sober optimization of human welfare against ecological damage.

[1] https://en.wikipedia.org/wiki/Generation_IV_reactor

Renewables definitely have those downsides. Especially if you look at the recycling procedures of solar panels and led batteries.

cf: Other link on the front page of HN: https://www.wired.com/story/solar-panels-are-starting-to-die...

Do you know what? Private industry doesn't care about nuclear. The only way to build nuclear is through government projects which is why there is immense pressure by nuclear companies to publicly dismiss everything that can support itself. Companies set up their own coal plants, natural gas plants, solar farms, wind farms and so on but what they don't do is build their own nuclear plants. Come up with better power plant designs and maybe then private industry will be interested.

There are better power plant designs, but regulations are based on designs from 50+ years ago, and thus no one has built a new safer design since.

There aren't 6 billion permits, licenses, and regulations to comply with when setting up a solar farm. On top of this, you don't assume much liability when installing a solar panel. You do when creating a nuclear reaction. Pouring the concrete and building the core of a nuclear plant is not inherently more expensive than plenty of other projects that private industry funds.

The cost overruns in nuclear come from necessary but burdensome regulatory requirements.

Wind turbines can be offshore. You can buy a wind turbine "off the shelf" and have people without nuclear training plonk it down wherever you want it, approximately as soon as you can stump up the money and get planning approval.

The USA has been adding wind turbines at the rate of ~four a day every day for the last fourty years, for a total of some ~60,000. In that same time the USA has started 4 nuclear power plants[1], all in 2013, all unfinished/in progress. The UK has ~11,000 wind turbines. We have 1 nuclear plant started construction in the last 30 years (Hinkley C) and it is two years in, and over budget. UK has five more proposed nuclear plants, and of those two are shelved and one cancelled[3].

It's not proven that the UK or USA still has the ability to build working nuclear reactors, or the ability to organise and approve and fund them - look at this link [2] about the last few years of the UK government changing, making, and cancelling approval and funding plans. Or that the UK will be able to source and transport nuclear fuels and wastes after Brexit.

Even putting all that aside, and assuming the world can source enough nuclear fuels for a massive expansion of nuclear power, and assuming we can overcome concerns about terrorism, and about getting a large increase in skilled people to build and maintain them, we can build and install wind turbines today, but if we start building one new nuclear plant a week it will be approximately a Trillion dollars (Hinkley point C in the UK is expected to be £23Bn+, the UK would need ~50 to go entirely nuclear for several Trillion pounds, the USA would need many more) and a decade or two to get a large amount of power generation from them. In two decades, wind and solar could blanket the country if we wanted, solar price drops, lithium ion battery price drops and other storage systems could make significant progress for a fraction of that money.

I'm not against nuclear in principle, but the first UK production reactor in 1966 was £30 million which is about £0.5 Billion in today's money. In 2008 the government was estimating £2.5 billion per plant, the chairman of E.ON said it could be £5 billion per plant. By 2012 estimates were up to £7 billion. Hinkley Point C had an actual estimated construction cost of £20 billion. In 2013 Centrica withdrew citing higher than expected costs. By 2015 the UK government agreed to pay double-rate for electricity from Hinkley Point C as a subsidy of about £6 billion on top of the build costs. By 2016 the UK National Audit Office said that subsidy could end up being more like £30 billion all-in. In 2017 they revised that to £50 billion. In 2016 the construction cost exceeded the entire market cap. of EDF the French company supposed to be building it. By 2020 it's two years into construction and construction costs are up another £3 billion to ~£23bn and we're Brexiting. It's been described as the most expensive power station in the world. The UK government has banned the funding model used from being used on future power plants.

Realistically, are we going to be 5 years down the line from here, with costs increasing so much the project gets shelved unfinished, or EDF collapsing and unable to finish it? There has to be a non-zero chance of that happening.

[1] https://en.wikipedia.org/wiki/Nuclear_power_in_the_United_St...

[2] https://en.wikipedia.org/wiki/Nuclear_power_in_the_United_Ki...

[3]

There's not enough nuclear fuel in the world to power the world for more than a little bit (iirc 30 years). It can at best be used as a transition source or a supplemental source.

> There's not enough nuclear fuel in the world to power the world for more than a little bit

This claim is simply false. The argument in favor of this view involves a very narrow interpretation of proven reserves that excludes discovery. The argument you're making is the same as peak-oil-ism, and we all know how that turned out.

https://www.world-nuclear.org/information-library/nuclear-fu...

Thanks for the link. I guess I hadn't read enough about this. I still am uneasy about using nuclear power for everything because of the risks and waste. I'm aware that alternate, safer designs exist though they are not commercially proven and often have unsolved problems with either logistics, scaling, or non-proliferation.

I feel that changes to lifestyle and solar power sharing across large geographic areas might be a better and more ecological approach, though I can't quantify how everything would work yet.

The other aspect to discovery though is that mining ever more hard to recover fuels results in escalating ecological damage. Fracking isn't something we needed to do but is possibly responsible for small earth quakes and various kinds of local destruction and pollution for example. I don't know much about uranium mining, but I suspect that it is a very toxic enterprise filled with radioactive acids and tailings.

Please don't post in the flamewar style to HN.

We detached this subthread from https://news.ycombinator.com/item?id=24253613.

I was just thinking farmers had it to easy harvesting their crops.

If we take the solar panels off the 1% of roof space they are on and move them far away from the place we use the actual power, we could do this.

The attention span of the environmental movement is quite amazing at times.

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