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Comment by svara | Hacker News Reader

I've been diving into this literature a bit recently, and it's been mostly encouraging. Affordable clean energy is realistic.

Clean energy sources are typically the cheapest sources of energy [0]. The intermittent production issue is solvable: At ~150 $/kWh storage, a combination of storage and renewables is the cheapest energy source 95% of the time [1].

The cost of different energy storage methods is coming down exponentially [2]. A combination of Li-Ion battery (short-term), pumped hydro (medium-term) and hydrogen (long-term, i.e. seasonal) storage is probably how to smooth out the burstiness of renewable energy production eventually [3].

When green hydrogen infrastructure is commonplace, the hydrogen can also be used to make synthetic jet fuel and feedstocks for the chemical industry.

[0] https://en.wikipedia.org/wiki/Cost_of_electricity_by_source

[1] https://www.cell.com/joule/fulltext/S2542-4351(19)30300-9

[2] https://www.nature.com/articles/nenergy2017110/figures/1?pro...

[3] https://www.sciencedirect.com/science/article/pii/S254243511...

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I've read about a couple of solar projects that projected x/kWh and turned out to be much worse in production.

Pakistan's big deployment is one example, it was planned to be 100MW but only produced 18MW. Mostly because they didn't factor in the dust that would cover the panels, keeping them clean was very expensive (I'm curious how this applies to other proposed desert deployments). Nor factoring in the typical malaise of public projects adding significant delays/costs, which is hardly unique to Pakistan when it comes to major infrastructure in 2020.

https://en.wikipedia.org/wiki/Quaid-e-Azam_Solar_Park

Then there's the famous Solyandra which got half a billion in US tax payer money and flopped without ever being competitive price-wise: https://en.wikipedia.org/wiki/Solyndra

Tesla's famous Australian battery factory only has enough to power 30k homes for about 1-2hrs each day. It was on-schedule, which is rare, and also makes money but scaling it up to millions of homes to make a real dent in coal would be much more challenging, especially sourcing enough lithium.

I think it's safe to take any cheery prediction from green projects and add 1.5x time/production costs and/or minus 30% of the expected output.

Note: I'm not trying to rain on the parade, I'm otherwise all for this stuff as long as it's realistic on a large scale.

Tesla’s famous Australian battery farm (not factory) was designed from the start as a frequency maintenance source, not as large-scale storage. It’s designed to be able to source or sink large currents with nearly instantaneous response, which is ideal for responding to sudden rises or falls in production or demand. The farm has been successful in both significantly reducing the spot price for power, but also in making money for the operator. It’s a huge success story.

> It’s a huge success story.

The caveat being the South Australia has a power grid that is sometimes a contender for the worst managed (and most expensive) electricity grid globally. Or at least highly challenging to get it working smoothly.

So the battery is a huge success story and we'll see more like it - but the conditions where it succeeded are not necessarily where the gird wants to be.

> worst managed (and most expensive) electricity globally

That's a strong claim. Wholesale electricity prices in South Australia are currently around USD$45/MWh.

My understanding is that South Australia has historically always had the highest electricity prices in Australia due to dependence on gas generation within a small market controlled by two players who took advantage of their market power, but that this is starting to reverse now due to the shift to more renewables over the last decade, and South Australia may now be on track to have the cheapest electricity in Australia.

Solyndra's failure had nothing to do with technology at all. They failed because Chinese manufacturers undercut them in price, quite severely. Allegations of dumping (or fraud, on the other side) notwithstanding, what this says is that solar is actually much cheaper and more readily available than Solyndra's investors expected. And that's sort of the opposite of your point, no?

Similarly the Tesla plant is doing exactly what it said it was going to do, when it was supposed to be finished, within the budget it had, and AFAIK is making money. You're asserting that it can't scale because it... worked?!

As far as the Pakistani misdesign, yeah, I'm sure that's going to happen too. Nothing works perfectly.

Nonetheless this seems like a pretty oddly constructed list of reasons why solar is "much worse in production". It seems to my eyes like it's doing much better than expected.

I don't disagree on the point that they were undercut in price. But they were also undercut in price because commodity normal PV panels composed of 156mm polycrystalline or monocrystalline cells (60 or 72 cells) are much cheaper to manufacture than the weird proprietary system they developed. They are also much cheaper to mount on large roofs (home depot/walmart warehouse sized) or on large scale 300kW+ ground arrays.

Ordinary 60 or 72-cell panels are DEAD SIMPLE in their construction. It's a sandwich of a backing material, encapsulation for the cells and soldering, glass in front, with an aluminum frame and a junction box on the rear.

Solyndra "panels" are fragile, hard to transport, hard to mount, everything about them was a pain in the ass.

You can't fund potentially breakthrough innovation and research and only get one tail of the distribution. It's a good thing, not a bad one, the the US government providers funding, and in this case, interest free loans for projects that sometimes fail.

As I always say in software projects, if some of your tasks aren't failing, you're not being ambitious enough in your goals, or are not ditching ineffective work soon enough.

Solar power is alive and kicking in Spain and increasingly more cost effective (removing the need of subsidies since 2018).

Spain just shuttered half of their coal capacity at the end of June 2020 partially due to this (also because of emissions requirements owners didn’t want to meet), and intend to shutter the rest by 2025 (additional wind power and pumped hydro for storage is coming online in that time).

https://english.elpais.com/economy_and_business/2020-06-29/s...

he is arguing that your brita pitcher working does not mean it's suitable to scale for your city's water purification system. the success of the tesla deployment for its intended purpose hence means zero for large scale systems.

apparently you also think the chinese government using its people's money to sell panels at a loss makes the panel cost less to produce, proving the opposite of his point?

do you actually have a point, beyond 'your point is false because of this fake argument i made up?'

I'm honestly curious what is the big challenge with keeping large arrays of ground mounted panels clean in Pakistan. The prevailing wage for unskilled labor for a 6 day a week, 45-hour work week for one laborer to clean panels is probably about $250-300 a month (USD equivalent, in rupees) in that area. That would be a good wage compared to construction work or farm work in that region.

With some basic equipment like rolling carts with sprayers and squeegees on extension sticks, how many individual 72-cell sized panels (1.99 x 0.99 meter size) can one person clean in one day? Multiply by probably 4 to 6 full time staff positions.

Quoting the Wikipedia page cited above:

> It required one litre of water to clean, each of 400,000 installed panels. A total 15 days cleaning cycle required, 124 million litres of water enough to sustain 9000 people, while rain in Cholistan desert is rare and far between. Providing such huge amount of water in desert terrain, became a challenging and daunting task for management team. Besides, the manual cleaning methods allowed setting of dust before it was re-cleaned.

This seems kind of like a bullshit excuse where they just didn't really want to fix the issue. There are a number of waterless cleaning systems that have been available for years, for example [1]. Additionally, why the hell would you throw away the water used for cleaning? Filtering the dust particulate out of the water is pretty straightforward (hell, you can go from muddy to fairly clean water with nothing more than a cotton t-shirt), then you reuse it to clean more panels. 1L/panel with even basic reclamation is ridiculous.

[1] https://www.youtube.com/watch?v=wdidbRQaUEY

Agree. They could probably just have people walk around with blowers to blow the sand off.

I would suggest that blowing off sand with a strong airstream would scratch the solar panels, further reducing their efficiency. Or maybe there's other problems; in any case, I find it somehow ignorant to assume that nobody in the Pakistani government has ever heard of or considered a blower (or a broom).

I assume they have heard of blowers and probably knew sand would be a problem with this install. My take away is that project was a bad faith effort to serve as a strawman against renewables for oil. This is an engineering problem not a technological problem of solar panels. Having skipped over it implies questionable motivations.

Would those be a gasoline powered blowers ? ( ͜ʖ)

Perhaps a step down transformer that directly feeds a dyson blade style blower at one of the edges of each panel. More up front equipment and infrastructure cost but no employee wages. However I'm sure this is full of holes due to cost multiplied by number of solar panels and the number of transformers needed. It is also only able to clean only during the day assuming no battery or pumped hydro storage.

What about solar powered golf carts with blowers?

I wonder how much of the 1L evaporates.

During the night and very early morning, probably very little.

Evaporation often happens at night because of the temperature differences.

> Evaporation often happens at night because of the temperature differences.

I'm not sure the phrase 'temperature differences' exhibits a profound understanding of evaporation.

If a location gets 45c (as per GP's reference) during the day, this doesn't necessarily speak to night time temperatures.

I'll note that Bahawalpur's temperature profile is available at:

https://weather-and-climate.com/average-monthly-Rainfall-Tem...

For the three hottest months of the year the average lower temperature is around 25C, which suggests quite a low evaporation rate overnight.

It would be great if you could provide some more detailed insights.

What about a fleet of automated drones/machines which clean the panels by blowing air? I don't know, but it seems like physically scrubbing the panels would take more machinery (heavier), more moving parts (break down more easily), and the scrubs themselves would have to get replaced & careful not to be abrasive (not sure how much the panels "care" about it though). These "dusters" could run off the excess power too. I read somewhere else in this thread that one problem was the solar park would occasionally over-produce - maybe the fleet works whenever there is an overproduction, or after a certain amount of time has passed (we _must_ clean them now and can't wait until the next time of overproduction).

If you're going to clean things via physical automation, you could probably work out the energy cost involved ~reasonably well over time.

You can a have a quadcopter drone clean every panel with a soft brush/microfiber cloth and return to base at recharging station and repeat.

Have a swarm of these and cleaning will not be an issue.

but maybe they can use seawater for cleaning?

Would the salt be abrasive & damage the panels/coating decreasing efficiency?

I would imagine another challenge is the transporation costs. The nearest fresh water source appears to be Sutlej River ~18 KM straightline. The nearest seawater source appears to be the Arabian Sea, ~800 KM straightline.

The cost to a problem like this would never be labor as that can be trivially automated if it ever gets costly enough. Water is expensive at these scales.

That being said, it's probable that there could be solutions here. Automated scrubber/blower might be able to get most of the efficiency back without the cost (whether integrated into the panel or a robot on a track). Could potentially use any water more judiciously too when needed (moisten a scrub rather than blasting it with water). Don't know enough about the project but I would hope the domain experts responsible for the project would have considered something I only thought about for 30 seconds & there are reasons that they don't do that.

> Would the salt be abrasive & damage the panels/coating decreasing efficiency?

I imagine some glass coating should be cheap enough and efficient solution to implement.

> The nearest seawater source appears to be the Arabian Sea, ~800 KM straightline.

Sure, such plant has to be constructed near seawater source.

According to the Wikipedia article cited it takes 30 people 10-15 days to clean all 392,158 panels fully. That sounds like $100,000/y in raw wages but it seems to be limited by water supply more than raw labor cost. The dust being cited as 40% of the panel efficiency loss and not always being an issue depending on the season also drives some of that RoI down, looks like a good portion of the loss is due to the heat as well. By far the biggest costs seem to have been with corruption from choice of renewable source to choice of contractor vs operation of the actual installation.

You're off by a factor of 10 based on wages for cleaners in Pakistan which is about $1/hr.

http://www.salaryexplorer.com/salary-survey.php?loc=164&loct...

Using the average number from that source you get 356,000 PKR yearly * 30 people = ~$64,000, even using the low end from that site is only a factor of 2 off not 10. The numbers were actually based of the high end from above in the chain "for one laborer to clean panels is probably about $250-300 a month (USD equivalent, in rupees) in that area. That would be a good wage compared to construction work or farm work in that region." which corresponds very well to the high end from your source of 540,000 pkr.

This comes out to ~$97,000 which is how I came up with about $100,000/y.

Just to note this isn't something you do for just one month per year if that's how you came to a factor of ~10.

My apologies, I read your original statement of raw wages as being for the 10-15 days you were talking about, rather than yearly wages.

And there are also many PV cleaning robots available. This is not self-driving car stuff, it's off the shelf technology.

Windshield wipers are a mature and cheap technology that seems applicable.

They are designed to clean water off glass. I've never lived in a dessert area so I may be wrong, but I expect they're not great for cleaning large amounts of dry dust and dirt off at least without using huge amounts of water.

I'd adapt it, of course. Not literal store bought wipers.

Some kind of brush is probably what you need for dust.

Solyndra didn't lose tax payers money, it was part of a portfolio of companies that made the US government money. It was literally the US government being innovative, effective, and responsible with tax payer money. By singling out Solyndra like that and calling it a waste of tax payer money, you fundamentally make it harder for the government to continue to operate in the manner described. Breakthrough technology does not happen without failure, and focusing on the failures, instead of the successes only serves to limit our future capacity for breakthroughs.

> Pakistan's big deployment is one example ..

A valid example of what can go wrong when you pick the wrong technology, don't do small scale trials first, and rely on government oversight. (Refer the Background & Operation section of the wikipedia article -- toe-curlingly alarming, yet ultimately unsurprising.)

They almost definitely should have pursued concentrated solar thermal. It partly solves the 'storage problem', provides power well into the evening, doesn't need more water than they have to clean it, and improves magnificently with high temperatures (the wikipedia article cites the problem of regular 45C days, which are above the 25C optimum temperature for PV panels).

Given all this was known and understood before they broke ground, this sounds like a traditional government project problem -- susceptibility to corruption, vanity, hubris etc.

> what can go wrong when you [..] rely on government oversight > this sounds like a traditional government project problem

I don't know why you're trying to turn this into an "obviously govt can't do anything" point. There are plenty of very well-run governments who would have ably foreseen and solved these problems. And no doubt there's any number of private companies who would have screwed up just as badly.

Trying to tar the entire idea of government with Pakistan's performance is pretty bad faith IMO.

> > what can go wrong when you

You're mis-quoting me. Is this intentional?

I understand paraphrasing, but there's better (and more accurate) ways of doing that.

> I don't know why you're trying to turn this into an "obviously govt can't do anything" point. There are plenty of very well-run governments who would have ..

FWIW it wasn't a 'no government can do anything' claim.

I have no doubt that there are a number of government agencies that can do things.

The fact that this particular project delivered a measurable 20% of projected outcomes is the point.

If you have some alternative interpretations of this outcome, they'd be very welcome.

> And no doubt there's any number of private companies who would have screwed up just as badly.

Are you suggesting I can't claim something is bad -- because something else would be just as bad?

> Trying to tar the entire idea of government with Pakistan's performance is pretty bad faith IMO.

This is a bold leap, and no faith is involved.

Amen. Not just bad faith; ignorant, myopic and ahistorical.

> this sounds like a traditional government project problem -- susceptibility to corruption, vanity, hubris etc.

said the person on a web forum (the web comes from CERN, a gov project) over the internet (the internet comes from DARPA, a gov project) on a computer (ever heard of the ENIAC? a gov project)

Tech bros mouthing off off-topicly about the government is the most tedious and boring thing ever.

https://techpinions.com/its-not-just-the-internet-how-govern...

> Amen. Not just bad faith; ignorant, myopic and ahistorical.

Referring to GP's wikipedia reference, can you explain the two 'for unknown reasons' on a) why the original (Canadian) contract was not engaged, and b) the Turkish project was not engaged.

What precisely was ashistorical about any of my post?

> > this sounds like a traditional government project problem -- susceptibility to corruption, vanity, hubris etc.

> said the person on a web forum (the web comes from CERN, a gov project) over the internet (the internet comes from DARPA, a gov project) on a computer (ever heard of the ENIAC? a gov project)

I really am bewildered.

Are you claiming that because I'm using the Internet I am not authorised to claim that any government project in any country at any time is beyond questioning?

> Tech bros mouthing off off-topicly about the government is the most tedious and boring thing ever.

Goodness.

I'm sorry you're bored, I'm not a tech bro, claims of poorly run projects within the land of the pure isn't off-topic to the claims made.

Please go grind your axe somewhere else.

I'm assuming that since axes weren't government inventions that we're allowed to talk about them?

Is solar thermal still a going concern? Are new plants still being built?

It seems to be in a lull, but the technology is still maturing. I suspect as the generation + storage costs continue to shift, it'll be adopted more eagerly. PVCs cost reduction has been a boon for that industry, but that tech, of course, ignores the storage problem.

Reading about some of the missteps of CSP, much like the above, they seem to be share similar traits of government mishandling, bureaucracy, dodgy dealings, etc.

EDIT: In any case, a naive interpretation of the Pakistan project cited -- if it truly is getting ~20% of anticipated power, cost per unit is 5x forecast, at which point a CSP would have been better value for money.

Why wouldn't solar thermal have the exact same issue with mirrors getting dusty though?

I suspect that solar thermal is in more than a lull; I suspect that it's been obsoleted by PV and we aren't going to be seeing many new installations at all.

I suspect there's several answers to your first question. For example, the mechanical factor of parabolic mirrors that are typically used for CSP's - they can provide more shelter in terms of wind-deposited dust than flat panels all angled in the same direction (a la PV panels).

I also suspect that mirrors are less sensitive to dust than PV cells. And that it's cheaper to just install more mirrors (flat reflective surfaces) to compensate for anticipated dust build-up, than photovoltaic panels (per unit of area or per unit of power generated).

But, really, I expect there's a fair bit of research on this subject already out there.

As I intimated, it's probably not so much an obsolescence issue, as one of pushing the storage question aside. CSPs address generation, with some ephemeral (cloud, evening, etc) storage capabilities. As per the standard observation - it's going to be a blend of power generation and storage technologies that sees us through.

Good points. I still think that, overall, money talks, and the vast majority of solar installations are not managed nearly as incompetently as this one was (i.e. not forgetting to take into account sand in a desert). So the fact that close to 100% if not 100% of new solar installations are PV over solar thermal really does mean that once you take all these factors into account, PV is still more cost-effective.

The storage issue is interesting, but doesn't matter so much to most plants since they tie into a larger balanced grid, and battery storage is coming down in cost at the same exponential rate as PV. These same advantages are not accruing to solar thermal. So I do think we are seeing the death knell for solar thermal, even when energy storage is desired alongside peak production.

Agree up to a point.

Storage can't be ignored - and the 'balanced grid' that we're all part of relies heavily on burning fossil fuels for both baseload coping with peaks (sun goes behind a cloud or the horizon, or the wind stops for a while). As we decom more of the fossil fuel systems, a more robust & scalable storage system, even a relatively ephemeral one, will become more compelling. (my prediction : )

> doesn't need more water

>improves magnificently with high temperatures

Thermal solar is a solar heat energy source + classic steam turbine. The efficiency of a thermal->electric converter (turbine) is largely governed by the difference between the hot and cold side.

Increasing both the hot and cold side temperatures equally would not increase efficiency, AFAIK it would actually decrease efficiency, and without lots of water, they can't use evaporative cooling either.

> Increasing both the hot and cold side temperatures equally would not increase efficiency ...

Hence the C in CSP.

Contemporary molten salt CSPs operate at ~700C, so the difference between the concentrator and ambient air temperature would be 3% (at 25C) and 6% (at 45C).

In other words, a 3% difference. Perhaps measurable at the output, but certainly not significant.

New CSP designs are coming along that are working around 1000C, which would render that delta even more negligible.

In contrast, while PV cells vary, I believe max power temperature coefficients of around 0.4% / 1C is a standard figure.

That means at 25C your panels are losing 10% of max capacity, but at 45C that number goes up to 25%.

A massive reduction in capability.

I was merely pointing out that CSP efficiency likely doesn't increase with increasing ambient temperature, it's just inherently more tolerant.

As an aside, your calculations are improper, even though results are close enough. 0℃ is merely 273.15K and the temperature at which water tends to freeze. E.g. PV efficiency is usually quoted at 25℃ (or 300K), so at -20℃ they could generate cca 120% of "max" (rated) capacity.

Tesla's Australian battery was not for storage, it's for power quality.

It's for both - 70% of capacity is for grid stability and the other 30% is for storing power when it's cheap and selling it back when it's expensive.

the point of the tesla battery in south australia wasnt to provide base load continuous power it was to provide close to instant peaking power to smooth the grid it was directly competing with natural gas peaking plants. (which it beats)

I am curious, how do Solar Parks in India work? The Quaid-e-Azam park is in the Thar desert and the desert extends to India as well in the state of Rajasthan. India seems to have built a solar park at Bhadla, ~300 km away from Quaid-e-Azam, in a different part of the same desert.

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

Apparently Bhadla is the world's largest solar park. I wonder if the two countries can co-operate on this (I know relations are mostly hostile currently)

Interesting, they seemed to be attempting to solve the cleaning problem via automation from an Israeli company:

> In December 2016, Solairedirect signed an agreement with Ecoppia, a PV panel cleaning solutions developer, to provide automated cleaning solutions to the project. Due to the park's location in a desert region, it is prone to dust storms

https://www.pv-tech.org/news/ecoppia-to-provide-cleaning-sol...

Hopefully the project eventually does reach the 2000MW scale it plans. It's not clear from the Wiki how far along it is or whether it's currently operational. It mentions opening targets for Dec 2018.

Softbank is involved for 500MW which is one red flag :p

How high does the dust go? Maybe they could cut down on cleaning by just building a wall around the power plant, or add some fans to keep the dust out?

Well, supposedly the Amazon is kept fertile by dust from the Sahara, so I'd guess pretty high.

A little Its a little disheartening that current Lithium-Ion battery storage is at ~$350/kWh and is only projected to hit ~$150/kWh in 2050 [0].

[0] https://www.nrel.gov/docs/fy19osti/73222.pdf

Either the government report you cite is overly pessimistic, or bloomberg is overly optimistic: https://about.bnef.com/blog/battery-pack-prices-fall-as-mark...

$350/kWh is still ridiculously cheap. You could build a good off-grid battery system for $7000 or so, which for many people would pay itself off in a few years.

Seasonal energy storage would be astounding. Combine an overkill of renewable energy with seasonal energy storage via hydrogen and you'd have as much energy as you could want.

Regarding [1], the article quotes production costs of USD 50/MWh for renewables, and USD 100/MWh for coal (graph 3).

You/[1] is saying that with storage costs of USD 150,000 per MWh, renewables can be competitive? It doesn't compute, unless I misunderstand something.

I think that $150000 per MWh buys you a storage system you can use more than once, rather than being the cost per usage of the storage system. After a few years, the amortized cost drops below coal generation.

Just from your numbers, it sounds like it's a good deal as long as you need to (grid) store less than 1/3 of your generated/consumed energy.

There's a factor of 1000 there.

150,000$ / 3,000 charge cycles (~8.3 years) = 50$/MWh = 0.05c/kWh.

Batteries last longer than one cycle...

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