See-Through Solar Is Tomorrow’s Threat to Oil | Hacker News Reader

See-Through Solar Is Tomorrow’s Threat to Oil

bloomberg.com

89 pointsantr68 comments

We are already struggling to make low cost solar panels that have a high efficiency using light absorbed from the visible spectrum (which accounts for most of the sun's spectral irradiation [1]).

Furthermore, you can't just have solar cells that absorb a wide range of the solar spectrum, there is an optimum band gap for these materials of around 1.34 eV [2].

This means that the most popular solar cells in development, namely CIGS and CdTe are already occupying the niche for maximum efficiency. The challenge now is finding new materials that are cheaper to make and show greater efficiencies whilst not relying on the use of rare earth/toxic elements.

(Hint: the real development in this area at the moment is hybrid perovskites [3])

Basically, this is irrelevant cruft.

[1] http://zebu.uoregon.edu/~imamura/122/images/solar_spectrum.p...

[2] http://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit

[3] http://www.nrel.gov/ncpv/images/efficiency_chart.jpg

(source: currently doing a PhD in a new photovoltaic materials)

As they say in the video, even if these are half as efficient as regular solar panels, you could still see them on other types of surfaces where current solar panels can't be used right now: think windows or smartphone screens.

We could also see them on large buildings or rich people's villas whose owners perhaps want to use energy from solar panels, but don't like the "look" of solar panels on those buildings. So then the choice becomes using this or using no other solar panels.

i get smartphone screens, but it's not that every other surface has been covered already or that you can't transport electricity from A to B.

We really don't have a shortage of space to put solar panels. The challenge is making solar panels that are cost effective (e.g. $ per Watt).

In response to your edit: That is a possibility, that yes they may find a niche in the fancy of the rich.

But the point I'm making is that the article is hyperbolic and misleading.

Transparent solar is not the future of utility scale power generation. It is not going to solve any of the problems currently holding back solar power from becoming ubiquitous.

Volume is key. Volume to push price of silicon panels down to have electricity reach grid parity levels. An intesting project (which I think has been ditched or put on hold) is/was DESERTEC. Install thousands of PV pannels in the Sahara dessert, and connect this to energy-hungry Europe thorugh a new HVDC grid connection.

Source: http://en.wikipedia.org/wiki/Desertec

> The challenge is making solar panels that are cost effective (e.g. $ per Watt).

And the other key challenge is nighttime.

If we had relatively low-cost utility-scale electrical energy storage, we would see a much higher rate of solar energy adoption. More so in sunny places, but that would then drive down the cost for everyone.

I keep hoping something like a flow battery will turn out to be practical, where to size up the storage, you just need bigger storage tanks.

This is a great point. We shouldn't ignore other efficiencies though. When used on the building envelope, light energy that would otherwise heat the building is converted into electricity instead. Assuming a reasonable efficiency for the conductors and inverters, this reduces the overall building demand. Even small reductions in demand can have huge price benefits for wholesale electricity buyers during expensive summer months (i.e. large commercial buildings). Hence, even if these panels are less efficient than opaque panels (and really how could they not be?) there may be other ways they can make sense from both energy savings and cost perspectives.

Now your window needs wiring. And an inverter. Would be more effective to coat it or tint it or put up some blinds.

Why couldn't you collect the solar energy from the outside of the window and put up blinds to block the light from the inside of the window? Putting up blinds won't generate any electricity.

What if we could design a solar cell that could shift from transparent to opaque on demand? Instead of putting up blinds, simply move a slider or tap a button or what have you, and suddenly the amount of light coming in is dimmed, and the energy being captured is increased. Seems like a win-win to me, if it were possible.

Solar-panel covered shuttering could do that.

Well blinds would presumably block the light you want in (visual spectrum). Furthermore, anything that isn't reflected back out serves to heat the building. Absorbing the energy in a PV material takes some fraction of energy that would otherwise become heat and turns it into something valuable.

Efficiency is very important but just one-big factor to consider in your application. Less efficient panels can have other benefits that justify their use. Crystalline silicon panels are more efficient than thin film but thin films are lighter and so can be used on roofs that don't support the heavier panels.

Blinds would block the light after the light has already passed through the solar panels. You get the shade plus the electricity.

You can't make single cells that absorb a wide range, but you can layer cells that absorb different spectras to achieve a much higher absorbtion in aggregate.

> See-Through Solar Is Tomorrow’s Threat to Oil

> ...screens and windows that soak up light could power your home or your phone

These two things don't compute. Oil is mostly used for mobile energy, and solar is mostly used for stationary energy. However...

I work in solar, and solar is a threat to oil. Why? Not because of transparent photovoltaics, but because it and batteries are getting so goddamn cheap. The Department of Energy has a goal of $0.06/kWh for solar by 2020[1], and Tesla aims to reduce the cost of lithium ion batteries by 50% by 2020[2]. That's only 4.7 years away.

When things get that cheap, we can just slap solar everywhere and have "gas stations" with excess inventory of swappable batteries for cars. It baffles me why more entrepreneurs haven't realized that 87% of the energy sources we use are going to be switching to other sources in our lifetimes[3].

[1]: http://energy.gov/eere/sunshot/mission

[2]: http://www.greentechmedia.com/articles/read/Teslas-Giga-Batt...

[3]: http://www.pvsolarreport.com/the-next-internet/

"It baffles me why more entrepreneurs haven't realized that 87% of the energy sources we use are going to be switching to other sources in our lifetimes"

What leads you to think entrepreneurs haven't realized this? What should they be doing once they do realize it?

My startup is in the SfunCube solar startup accelerator program[1]. So far, all of the entrepreneurs who have applied to the program are from within the solar industry (i.e. they previously worked at a solar company). Additionally, I organize the SF Cleanweb meetups[2], and we rarely see people from the normal tech companies/startups come to events to learn more about the space.

I don't really blame anyone for not realizing the huge opportunity in solar. It's not a very visible industry and used to be primarily a hardware space. Software has only come to the forefront in the last few years due to soft costs being such a huge problem[3]. If you're looking for an industry that desperately needs software and entrepreneurial talent, I'd highly recommend solar.

[1]: http://www.sfuncube.com/

[2]: http://www.meetup.com/cleanwebsf/

[3]: http://www.nrel.gov/news/press/2013/5306.html

I'm not at all knowledgeable about the solar industry, but I'm curious: how would software reduce the "soft" costs described in that third link (NREL)? It seems to me to be a bunch of costs related to the actors involved, and I don't see how software would help with that. Also, do you have examples of such software?

Sure! My startup, UtilityAPI.com, is an example of one that is targeting customer acquisition soft costs (10% of total installed cost). When you want to write a proposal for someone thinking about going solar, you need their utility usage and billing history. Collecting that data is currently a very time consuming and painful process, so not only do you spend a lot of man-hours on it, you also lose a huge portion of your funnel at this step.

We are building software that automates that utility data collection process, so solar companies can just bake it into their online forms/apps/internal tools. We estimate we can shave 5-10% off the installed price of solar due to time savings and increased conversion. The Department of Energy agreed and recently awarded us with $25k to build SDKs for our API (with the opportunity for $100k more in May)[1].

[1]: http://catalyst.energy.gov/

Ok I see, you're saying that hidden away in the various strata in that graph are, e.g., process inefficiencies which software can eat away. I was naively looking for something that would solve many categories at once, and being an outsider I think of solar as mostly hardware (like you said). Thanks for the answer.

> solar

> not a very visible industry

Hah.

Entrepreneurs have realized this, but energy is far more difficult than people will admit. Even if this works and is cheap, the real issue is batteries. Batteries are expensive and their manufacture entails environmental costs. There is no free ride. Yes, Tesla wants to reduce the price of batteries, but that doesn't make it so.

If this works you need many multiples of battery capacity as production. That is a staggering amount of batteries. And batteries don't have a long life. How is the battery life on a 10 year old computer?

I don't really get the constant focus of the energy conversation on transportation (< 1/3 of total energy use). If, as you say, we can get solar energy to the grid for less than coal then we're getting close to the time when no one will ever build a coal plant again. Then accelerating economies of scale will cause the price to fall to the point where we're shutting down fossil fuel plants, then to the point where we can make biofuels with solar rather than fossil fuels. Now GHG emissions are down 75-90% with a set of mostly evolutionary technical advancements.

Some environmentalists might not like that process because it's market-driven and doesn't involve any economy-shrinking monastic self-sacrifice (e.g. Kyoto protocol), but it is the reason I'm reasonably optimistic about climate change.

Only about half of oil production goes to energy and transportation. The other half goes to production of synthetic materials like plastic. Look around you, oil production is not going away any time soon.

Only more reasons to stop using oil for energy and transportation - we need it for plastics.

I thought refining of oil was mostly separating the different hydrocarbons- or can gasoline be used to make plastic?

You can "crack" or "reform" any hydrocarbon to any other at the cost of some energy. Plastic tends to be ethane -> polyethylene, and the like. The fraction called "naptha" which is between ethane and gasoline in refining tends to be used as chemical feedstock.

The sources I could find say 4% is used for plastic and another 4% for the energy to make the plastic. Nowhere near 50%.

http://www.plasticoceans.net/the-facts/energy-consumption/

this is not even remotely true

http://www.eia.gov/tools/faqs/faq.cfm?id=34&t=6

Flagged for being totally hyped and factually incorrect (even the title is nonsense).

I really wished that people reporting on Solar/Wind and other alternative energy sources would at a minimum gain a basic level of understanding of the subject matter before writing nonsense articles like these.

what part of the video is "totally hyped and factually incorrect"?

Having "Bloomberg" in the title already works as a flag for me. I don't think I've ever been pleasantly surprised by any of their articles.

Life is just too short to click on Bloomberg links.

The efficiency of this technology is ~1%. It's no threat to oil, but regular solar panels (efficiency ~30%) sure as hell are.

I haven't had a chance to watch the video, but I question the thinking in various parts of this article.

The first thing that hit me was: Cell phones? Sure, they don't need a lot of juice so a tiny patch of solar could power them. BUT there's 2 problems: These panels work on UV and infrared. Unless your phone owner spends a lot of time outdoors, he won't be exposing his phone to that kind of radiation, neither of which is found (significantly) indoors. Second, where do people carry their phones? Where the sun doesn't shine - I'm referring to their pockets, of course.

I wonder about the efficiency of window panes on buildings too: UV and infrared are in short supply when the sky is overcast, whereas visible doesn't dip nearly as much. So this is low-efficiency technology capturing light that's mostly restricted to sunshiny days? I still think it makes a heck of a lot more sense to simply slap "normal" PV on the roof, or possibly the walls around the windows. This looks gimmicky to me and I'm not sure the author understands the technology.

They don't speak about the angles (vertical windows vs horizontal roofs) and how much can this impact the energy efficiency in practice.

Presumably it's good to have some vertical panels in a mix to produce energy in the late afternoon when the sun is low but I wonder if there is any quantified study available that would highlight whether or not this is worth the investment.

Absolutely. This reads like PR article to me.

Or maybe I've read the submarine [1] too much.

[1] http://www.paulgraham.com/submarine.html

This isn't related to the clear solar panels from the article, but there's been significant research on this for traditional solar panels as well as solar concentrators.

Bottom line is, the mix of panels makes sense for northern cities (e.g. Albany) but not middle (e.g. St. Louis) or southern (e.g. San Diego).

There's a great writeup with links to the raw data at http://physics.ucsd.edu/do-the-math/2012/08/solar-data-treas... (this entire blog is amazing).

gives me a rough idea how big your world is.

Here, take this clause and make sure to put it in an important place in every solar-revolution story (but not in the title of course!):

"The technology still has a way to go because the cells must become more efficient to prove cost-effective, but their promise is big ..."

Really dumb article. Photovoltaics are breaking through as we speak. 1/3 of new electricity generation capacity in the US was solar in 2014. Building integrated PV is not doing anything, and I suspect it never will, because why??

I guess this means we're hitting peak houseplant.

The only threat to oil is government subsidies going to renewables instead of oil. I'm not saying that solar technologies aren't important, but the technology will fall into place when the money is there. Solar is already able to compete with oil with subsidies favoring oil, so solar technology is already good enough. Of course better tech is better, but we don't need better tech to kill oil, we need better distribution of funds.

Oil is primarily used as fuel for transportation. How can I power my kilowatt car with these? How about flying a megawatt plane?

This seems more like a milliwatt application. Probably nice and useful for phone, but not to replace oil. The title is misleading.

What is the efficiency of this technology compared to the usual solar panels?

We need terawatt-scale energy sources if we want to meet actual demand. How many square kilometers of that glass do we need to install to meet that demand?

I think the goal is to replace every window with this, producing an uncountable (Google interview question about Seattle) square kilometers of electricity-producing surface. I think the efficiency has to improve before most people would bother replacing their windows, though.

> Oil is primarily used as fuel for transportation.

The use of the word "oil" tends to include gas too (and in many cases coal) as the word the press many times doesn't use is hydrocarbons. Gas (be it natural gas, shale gas) is very much a source of electricity production, around one third of all gas is used for electricity... it's almost 100 in the case of coal.

> What is the efficiency of this technology compared to the usual solar panels?

It's mentioned in the video: traditional cells c. 30% vs 22%. A 1/3 loss in efficiency. But then, their use is more flexible.

> How many square kilometers of that glass do we need to install to meet that demand?

"Dividing the global yearly demand by 400 kW•h per square meter (198,721,800,000,000 / 400) and we arrive at 496,804,500,000 square meters or 496,805 square kilometers (191,817 square miles) as the area required to power the world with solar panels. This is roughly equal to the area of Spain. At first that sounds like a lot and it is. But we should put this in perspective." Source: http://landartgenerator.org/blagi/archives/127

> Oil is primarily used as fuel for transportation. How can I power my kilowatt car with these?

Easy. You build batteries using energy from solar panels, and then you charge them with energy from solar panels.

After you mine rare earth minerals using energy from solar panels?

Simple perhaps but certainly not easy.

The tallest building in the world, the Burj Khalifa in Dubai, has a total of 120,000 square metres of windows. It's already got some solar panels that generate 690MWh of energy a year, as well as heating most of the water used in the residential bit. Obviously that's a special case (it's huge and it's in an ideal location) but it's not entirely unbelievable that other buildings could benefit from this sort of technology.

I think it would be quite tricky to connect all windows of a building with transparent solar panels. Anytime a window is repaired you'd need an electrician. Since they are less efficient than regular panels you have more maintenance for the same power. Its cool innovation and I hope than they can solve the huge logistic problems. Mandated roof panels seems simpler.

Good solar cells are 40ish% efficient? I'm not a photonics engineer but I wonder how much of the total energy is in the visible range.

Current solar cells are only cost-effective in limited scenarios, it's nice that these could go in more places but even if they reach cost parity with what we have today, the would be less power. We're going to need to see huge reductions in production cost or energy capture before this becomes viable.

According to Wikipedia[1], "sunlight provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts is visible light, and 32 watts is ultraviolet radiation".

[1] https://en.wikipedia.org/wiki/Infrared#Natural_infrared

Good research lab solar cells are 40% when actively cooled and concentrating light at 1000x.

Good solar panels for homes and solar farms are 15 to 22% efficient.

It's interesting that efficiency is the key figure that we use. The more pertinent numbers are surely break even point - how many years in a standard installation to return the energy needed to make the panels. The next key figure is probably (in a domestic install) how much of a households energy can be produced with a standard install.

In many ways efficiency is irrelevant. If a panel were only 5% efficient but that produced 200% of a families power requirements in a normal install and broke even after 1 year that would be awesome. On the other hand if a panel were 95% efficient and returned 5% of families power requirements and broke even in several decades that would be terrible.

It seems a rating that shows how long it takes a panel under [a properly defined] "average" solar illumination to pay for it's own construction (both in money and power) would perhaps be useful and not too difficult to test and verify.

Does this tech, or even regular PVs, break-even energy-wise? I.e. do they produce more energy during their life-time than it takes to create them? Because if not, then a widespread deployment will only make our problems worse.

EDIT: thanks for replies!

4-6 years, that's why we need to make them cheaper and not fancier.

Regular PV breaks even with ease, assuming sensible use of the panels (e.g. don't mount them in the shade, mount them the right way around, don't smash them up etc).

Look up "embodied energy".

Thanks very much for the term "embodied energy" - now I know how what to google for!

PV energy payback is typically on the order of 1 or 2 years.

If panels hang vertically can't you facet them to give a better angle? You'd also make a larger area of light incidence that way.

Again, this is tomorrows revolutionary technology. Im all for solar, I am excited by the prospect of solar! I work in an area that partially depends on the oil industry for a large portion of the work I do. As has been said in this thread, Oil is never going away until its gone, there is just too much utility to be had from the stuff. However, being able to generate electricity from our sun would be a great boon to our society and emerging nations. I think its great that research is being put into this, but what we really need for solar to take off is something akin to Moore's law for solar. It needs to get cheaper every generation by half for the same kwh. When we figure that out, solar will take off. If I can get mostly off the grid for a couple grand(not 10s of thousands) I will jump on board immediately.

It's true that petroleum is used in a lot of different industries, but the primary uses of petroleum are still energy production and transportation. Everything else happens because it's cheaper to use the byproducts of petroleum refinement than to dispose of them. If we weren't using petroleum for energy and transport, we wouldn't dig up oil just to make plastics--there are plenty of renewable starter materials that provide equally malleable organic compounds (soybeans, rubber, agricultural waste).

I disagree on that plant based plastics, and you are missing my point. My point on petroleum was just to say I derive some of my lively hood from commodity markets based on trading Crude, NGLS, Ethanol, and some other things like metals, coal, etc. Even though this is the case, I still am a huge proponent for solar! However, we need to focus on a systematic cheapening of solar output per dollar for mainstream use, not clear solar panels that don't even make use of the most powerful spectrum of light.(even so I am still mostly in favor of this research)

Which brings me to my second point and why I disagree on plant based plastics. Oil is way cheaper to make plastics with than any other organic element. Further when you devote arable land to something other than food there is always going to be market pressure that will drive up food prices. I have enough experience in commodity markets to know that ethanol is a losing proposition right now. If we stop making oil based plastics we are going to run into the same issues with unnatural subsidies propping up the market. I do wish that we could just stop pulling oil out of the ground and use our plant waste to make all the plastic we currently use, but it just isn't the case. Attitudes and consumption per capita would need to go WAY down for this to work out.

> However, we need to focus on a systematic cheapening of solar output per dollar for mainstream use, not clear solar panels that don't even make use of the most powerful spectrum of light.(even so I am still mostly in favor of this research)

Solar already competes with oil despite comparatively massive subsidies for the oil industry. The problem at this point isn't the technology: the tech is good enough (although better would obviously be better--I'm not saying more research isn't warranted). The problem is government misdirecting funds into non-renewables.

> Oil is way cheaper to make plastics with than any other organic element.

Petroleum is cheaper to make plastics with, and only because oil companies have already footed the bill of locating and drilling the petroleum. If petroleum-based plastics ceased to be the byproduct of a much more lucrative industry they would cease to be as cheap.

> Further when you devote arable land to something other than food there is always going to be market pressure that will drive up food prices.

I don't think you have enough data to say that. Corn and soybeans are very different markets, and that's not even looking at other potential plant sources of plastics. Not all plant sources of plastic would be detracting from food production.

so what would happen if you put the transparent panel on top of a normal panel?

It would lower to energy input to the lower, opaque panel. The transparent panel would "soak up" the infrared and ultraviolet energy first. The lower would only have access to visible light energy.

You end up with a really expensive solar panel. We already know the transparent panel is less efficient than traditional, so I doubt it would capture any energy that wasn't already being captured.

So this means we should destroy the ozone layer to increase the amount of UV, right? /s

"There not as efficient as traditional solar panels - http://i.imgur.com/kv6dAEw.gif "

Reply on news.ycombinator.com