[HN Gopher] Producing fuels from 1,500 degrees of solar heat
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Producing fuels from 1,500 degrees of solar heat
Author : doener
Score : 117 points
Date : 2024-06-25 10:43 UTC (4 days ago)
(HTM) web link (www.thechemicalengineer.com)
(TXT) w3m dump (www.thechemicalengineer.com)
| ttt333 wrote:
| I have no idea if technology like this will prove to be scalable,
| economically competitive, or even practical... but it does seem
| pretty dang cool as a concept
| jfengel wrote:
| It's a great way to say "Absolutely no more fossil fuels. For
| things that need hydrocarbons we'll make them. They cost more
| but it's better than cooking the planet."
|
| With a side bonus of not sending money to oil rich theocracies
| like Saudi Arabia and Texas.
| mgerdts wrote:
| With methane as an input, I worry that this will be hard to
| scale up to the point of no more fossil fuels. Can we get
| that much methane from biomass?
| jaggederest wrote:
| Considering agriculture and forestry combined produce about
| 5 billion tons of methane emissions a year, I don't think
| there's a shortage of availability.
|
| It'll be a lot more work to capture and direct all that,
| but the biosphere spins off plenty of decomposition
| byproducts.
| defrost wrote:
| Is it more or less energy dense than oil?
| The consumption of oil has steadily increased over the
| last three decades, totaling 4.53 billion metric tons in
| 2023,
|
| That's oil shipped and used, not methane drifting free
| from biowaste across the plant.
|
| How much can we _actually_ capture, how much energy is
| that, and how great is the conversion challenge to shift
| most cars to methane, etc?
|
| It appears a little larger than a handwave problem IRL.
| waldothedog wrote:
| > Can we get that much methane from biomass?
|
| I know that food waste generates a heck of a lot of methane
| in landfills, but I'd love if someone could add some rough
| napkin math on this!
| pfdietz wrote:
| Biomass availability in the US:
|
| https://www.energy.gov/eere/bioenergy/2023-billion-ton-
| repor...
|
| One would like to focus on existing streams before having
| to increase area used to grow biomass.
| tejtm wrote:
| be afraid.
|
| methane hydrates;
|
| strip mining ocean floors could keep fossil fuel
| consumption going at current rates for millennia.
|
| but before that we could get we stuff in the permafrost
|
| all terrible ideas ... so probable.
|
| https://duckduckgo.com/?q=methane+hydrates&t=lm&ia=web
| osigurdson wrote:
| Texas?
| wussboy wrote:
| Yup
| jfengel wrote:
| At the moment, Oklahoma next door is even more prominent:
| they just mandated teaching the bible in public schools.
| But it's much the same.
| selimthegrim wrote:
| Were you thinking of Louisiana?
| tomcam wrote:
| How is Texas a theocracy?
| pfdietz wrote:
| This is just using solar heat to reform methane from biogas. I
| was hoping it would be using solar heat for production of the
| reduced chemicals from water or CO2. This latter problem is much
| harder, but there have been proposals, for example using heat to
| reduce transition metal oxides with evolution of oxygen, then
| reacting the oxides with steam to make hydrogen.
|
| M2O3 --> 2 MO + 1/2 O2
|
| 2 MO + H2O --> M2O3 + H2
| jillesvangurp wrote:
| The main issue with CO2 is that the concentrations in air are
| pretty low. A couple of hundreds of parts per million. So, most
| synthetic fuel generation is bottle necked on getting enough
| CO2.
|
| If you are processing a kg of air, you'd be getting only a
| fraction of a gram of CO2. So if you want to produce say a ton
| of fuel, you are looking at processing many millions of tons of
| air.
|
| That's why a lot of synthetic fuel generation is often paired
| with carbon capture schemes or bio mass (like this one). But of
| course a lot of those carbon sources aren't actually that
| clean. Biomass sounds nice until you realize that farming is a
| big emitter of CO2. And generating fuel from carbon capture of
| course defeats the purpose. You capture it at great cost and
| then you create a fuel. Which you then burn and dump in the
| atmosphere.
|
| This particular scheme in Germany exists because of the
| influence of car manufacturers there. Companies like BMW are
| dragging their heels getting rid of their ICE car manufacturing
| operations and pretending that there are unicorn solutions like
| hydrogen, synthetic fuels, etc. are great excuses to keep their
| factories going for a few years longer. Of course EVs are
| eating their lunch at this point and they are now actually
| producing lots of those as well.
| chii wrote:
| > You capture it at great cost and then you create a fuel.
| Which you then burn and dump in the atmosphere.
|
| But if the need for carbon based fuels is not able to be
| eliminated, this is the next best thing. It is better than
| digging more of it out of the ground, and then burn and dump
| it into the air!
| jillesvangurp wrote:
| Mainly jet fuel. Cars and trucks will do just fine on
| batteries.
|
| The point with carbon capture is that the captured carbon
| still comes from fossil fuels. You burn it, you capture it,
| make fuel, and then you burn it again. So, it's slightly
| less worse than burning it only once but 100% of it still
| ends up in the atmosphere.
|
| Synthetic fuels made with biomass are more sustainable but
| only if the biomass is produced sustainably. Which it often
| isn't. Dumping a lot of CO2 in the air to produce corn and
| then turn it into ethanol would be the classic example here
| of something a lot of countries do at scale that isn't
| really all that green.
| usrusr wrote:
| > The point with carbon capture is that the captured
| carbon still comes from fossil fuels
|
| That's not a property of carbon capture, it's a property
| of the fuel coming in on the other side of the
| (stationary) process. We certainly won't be seeing carbon
| capture of jet fuel any time soon, so the fuel preceeding
| the capture will definitely not be the one produced.
| Think waste incineration, think bioplastics (don't waste
| that precious energy on some pointless biodegradation!),
| think single use paper, think moving the part of the
| natural carbon cycle that happens in bushfires and the
| like into a controlled environment.
| jillesvangurp wrote:
| Actually jet fuel is already being synthesized from a mix
| of biomass and captured carbon.
|
| A lot of the carbon capture schemes propose capturing
| carbon from coal plants or similar sources where massive
| amounts of fossil fuels are being burned.
|
| But you are right that there are clean sources as well.
| But mostly with carbon capture, the source is fossil
| fuel.
| usrusr wrote:
| Fossil burning plants that capture carbon do it for the
| greenwashing, not because there might be some use for the
| concentrated CO2. Renewable burning plants have little
| incentive to greenwash. Renewable burning does exist, and
| I suppose that group is much bigger than the tiny subset
| of fossil burning plants that actually do capture. If we
| include waste incineration plants in the renewable group
| (the true multifuel specialists) then the conclusion is
| that capacity is already abundant, and some of those
| might actually be considering capture (but their
| greenwashing pressure isn't remotely as big as in e.g.
| the coal business, where the greenwashing is nothing less
| than an existential last ditch hail mary attempt)
| pfdietz wrote:
| It turns out one place in the US where CO2 capture is
| actually already being done on a large scale is in
| bioenergy. As I understand it, 25% of the CO2 produced by
| ethanol production in the US is captured. I think it's
| mostly being used for enhanced oil production, but it
| _is_ being used.
| usrusr wrote:
| That's why for every very high value use case (see chii
| sibling post) you keep some low value use cases running that
| don't really require high energy concentration fuel. Burn
| shrubs, waste (e.g. bioplastics), whatever for heat and
| stationary power and capture that CO2. Low concentration
| fuels are well available in renewable form and will be
| forever. Bottleneck solved, at least as long as you don't
| imagine you could keep up fossil age consumption rates with
| synthfuels (you can't). Leave those many millions of tons of
| air to processes we already run on them anyways.
|
| You are right (also with that last paragraph), direct air
| capture is usually a scam. I might be willing to grant a weak
| exception to projects that put serial self-containedness
| front and center, e.g. terraform industries (not to be
| confused with terraform labs...) would certainly be
| overwhelmed if they tried to tailor a capturing biomass plant
| to the local situation with each installation. But even they
| should better spell out in their advertising "optional, could
| be substituted with:" for the DAC.
| generic92034 wrote:
| > Of course EVs are eating their lunch at this point and they
| are now actually producing lots of those as well.
|
| Are actual EV sales numbers reflecting this, in Germany?
| swiftcoder wrote:
| Despite their loud complaints about electric cars, yes. EVs
| sales are rising rapidly, and account for >30% of new car
| sales in the past year (and that's not counting PHEVs)
| generic92034 wrote:
| In the past year EV sales went very well, agreed. But
| recently I am seeing articles like this one:
|
| https://www.tagesschau.de/wirtschaft/unternehmen/vw-
| elektros...
|
| A sharp decline in EV sales for Volkswagen, so they are
| asking for subsidies.
| pfdietz wrote:
| Battery prices are falling very quickly this year, so EV
| sales globally are set to explode.
| generic92034 wrote:
| That might be the case, but currently EV prices are
| generally still significantly higher than ICE car prices
| of the same class, hitting a slow economy in some EU
| countries. Maybe Chinese EV can fill that gap.
| pfdietz wrote:
| The proposal described was using methane from biogas. But the
| microbial decomposition of carbohydrates that creates biogas
| also creates CO2, in equal molar quantity:
|
| (CH2O)2 --> CH4 + CO2
|
| So, if you want to get as much fuel as you can out of the
| carbon in biomass, you want to use extra hydrogen (and in
| this case, it would mean they wouldn't have to separate out
| the methane in the biogas; just add hydrogen and reform the
| whole mixture). That extra CO2 is available without the need
| for expensive direct air capture: the plants already captured
| it. You could even directly hydrogenate biomass (or, perhaps,
| molecules derived from aggressive depolymerization of
| biomass) instead of going through biogas. This is Virent's
| approach. It avoids the need to break all the C-C bonds
| before recreating them in the synfuel.
|
| There have been efforts to use solar energy to directly
| gasify biomass. A company called Sundrop, out of Colorado,
| was trying to commercialize this 15 years ago. But then
| fracking dropped the price of natural gas and it all
| collapsed; the remnants of the company were bought by
| Chesapeake Energy (a natural gas producer) not long after.
| bradfitz wrote:
| > It uses an AI-based method involving drones to calibrate the
| mirrors 200 times faster compared to traditional techniques using
| cameras, Synhelion says. Precision is key to ensure the mirrors
| track the sun and efficiently reflect its light into a solar
| receiver at the top of a 20 m tall tower.
|
| Naively I would assume we know where the sun is and how to
| calculate the angles. What are drones and AI doing?
| ulfw wrote:
| Creating investor hype. What else?
| XorNot wrote:
| Calibrating out mechanical backlash and mis-alignment in the
| mountings I assume.
| usrusr wrote:
| As in fly a scanning pattern around the focus point and look
| for mirrors that blind the drone instead of frying the tower.
|
| Should be crazy efficient compared to the terrible
| alternative which would require something like deliberately
| de-focusing all other mirrors only to be able to verify that
| the mirror under test actually does project the sun where
| expected.
|
| Tempted to keep my initial upvote on the "investor hype"
| sibling, out of spite for all projects that do, but the
| ability to check arbitrary points in the nonilluminated
| volume for accidental illumination must really make do much
| of a difference I can't. Thanks for pointing me in the right
| direction!
| fl7305 wrote:
| > fly a scanning pattern around the focus point and look
| for mirrors that blind the drone instead of frying the
| tower.
|
| Or just put up a big black board with reference points on
| it, and point a camera at that?
| usrusr wrote:
| So then you have a live image of a big black board?
|
| The beauty of the misalignment patrol drone is that it
| does not leave you guessing wich one exactly of your
| large number of inexpensive mirrors is out of line. The
| culprit clearly lights up in the video feed.
| fl7305 wrote:
| You normally keep all mirrors pointed at the real target.
| Then take one at a time and point it at the black board
| off to the side.
|
| You can then use the camera image of the position of the
| sun spot on the black board to figure out your new
| calibration settings for this particular mirror.
| usrusr wrote:
| Ah, separate target for testing assumptions in isolation.
| ekianjo wrote:
| AI can be just a linear regression these days
| fl7305 wrote:
| > Naively I would assume we know where the sun is and how to
| calculate the angles. What are drones and AI doing?
|
| Yes, you know exactly where the sun is in a global coordinate
| system.
|
| The problem is that your mirrors are not fixed in that global
| coordinate system.
|
| You need to continuously re-calibrate the local coordinate
| system of the mirrors against the global system.
| sgc wrote:
| That is a simple math + sensor problem, not an AI and drone
| problem.
|
| https://www.topconpositioning.com/us/en/solutions/technology.
| ..
| vlovich123 wrote:
| I think it's more that it's been shown that a motor at each
| panel is more expensive than manually rotatable mirrors
| that are maintained by a smaller set of mirrors. For
| example, there was a startup a few years back that had
| robots on a rail system go to each panel and adjust it.
|
| The reason should be obvious in that the motors are higher
| maintenance systems so you don't want to scale with the
| size of your plant. I imagine drones are being used for a
| similar purpose: the drones further reduce how many
| adjusters you need vs rails and the AI is so that the
| drones can actually adjust the panels.
| fl7305 wrote:
| For concentrated solar polar, you need almost constant
| movement of the mirrors to keep tracking the sun well
| enough.
|
| So you need independent azimuth+elevation for each
| mirror.
| vlovich123 wrote:
| https://www.technologyreview.com/2012/09/04/184005/a-robo
| t-t...
|
| There's always a performance/cost target you're trying to
| hit. Sometimes it's not about performance at all costs
| and it's ok to sacrifice some optimality to get a much
| cheaper solution.
|
| So while the mirrors are independently adjusted, the
| there's a single motor robot on a rail that comes by and
| custom adjusts each mirror instead of having the mirrors
| self adjust locally at all times.
| remipch wrote:
| Interesting, do you have any links about this startup ?
|
| You say it's more expensive, do you have a rough estimate
| of the cost of such a panel (with or without motors) ?
|
| I'm asking because I'm currently working on a small scale
| automated solar concentrator and I haven't managed to get
| an idea of how much such a panel costs.
|
| I have only found some sun trackers for photovoltaic
| panels but they have different angular accuracy
| requirements than CSP.
| vlovich123 wrote:
| Not the startup I was thinking of as I can't find links
| for it but same concept:
|
| https://www.technologyreview.com/2012/09/04/184005/a-robo
| t-t...
| overcast wrote:
| Wasting investor money and using a disproportionate amount of
| the worlds energy to build chat bots.
| soist wrote:
| There used to be a company that tried to do this to directly
| generate electricity: eSolar (https://www.cbsnews.com/news/an-
| interview-with-esolars-bill-...)
| hn_throwaway_99 wrote:
| There are lots of companies that used heliostats to generate
| electricity, but that's not really a problem anymore. My
| understanding is that:
|
| 1. Photovoltaic panels absolutely cratered in price, so they
| are, generally, much more economical.
|
| 2. Not mentioned in TFA but these things have environmental
| concerns because they are basically bird killing machines. Any
| bird unfortunate enough to fly through the concentrated "death
| rays" is instantly fried to a crisp. So these things need
| solutions like drones to keep birds away.
|
| Generating gas from solar is an attractive option because it's
| then basically just another form of storage. But it would be
| great if we could generate gas from solar to power existing gas
| power plants. The primary problem is that the efficiency of
| generating gas from (solar-powered) electricity is quite low.
| theamk wrote:
| This sounds very cool, but "annually producing several thousand
| litres of fuel"?
|
| An average US car consumes ~1800 litres/year... So this 600 kW
| solar facility is just enough for one or two cars?
|
| A random search shows you need ~2kW worth of solar to charge your
| electric car daily, so this technology needs to improve a lot to
| be competitive with batteries. Hopefully they figure it out
| before they build the full-size plant.
| Animats wrote:
| > _" annually producing several thousand litres of fuel."_
|
| That's maybe 10 liters a day. Seems low for the size of the
| installation. A liter of gasoline is about 10KWh. So if this
| thing gets 5 hours a day of full sunlight, it's putting out 2KW.
| That's like 5 standard solar panels.
|
| Either I'm calculating this wrong or this is insanely
| inefficient.
| wolfi1 wrote:
| it is insanely inefficient. whereelse I read you need 3 liters
| of gasoline to produce 1 liter of synfuel
| ChuckMcM wrote:
| What is your measure of efficiency? I ask because the cost of
| sunlight is nominally zero so 10kWh/$0 is a really big number
| :-).
|
| Note that the article said that as a thermal plant it operates
| 24/7 by storing heat in a high thermal mass fluid. Another shot
| at this is Terraform Industries
| (https://terraformindustries.com/) which is doing something
| similar with direct PV -> Fuel (rather than using CSP)
|
| The "magic bean", the "trick", the "secret sauce" here is that
| there are huge swathes of land that are currently both high
| sunlight receivers and not used (can't farm them, no one wants
| to live there, think deserts) That could be used to crank out
| liquid fuel that has no issue being losslessly transported over
| long distances and for applications that are unlikely to run on
| batteries any time soon. Making fuel for those by taking CO2
| out of the atmosphere is a double win.
| roenxi wrote:
| The plant is physically quite large; the sunlight might be
| free but capital and deprecation will influence that ratio.
|
| Although if they can do this economically then good. I have a
| soft-spot for any solar farm that can be made to look a bit
| like a flower.
| chii wrote:
| > sunlight is nominally zero
|
| the investment into the panels is not free though. But i do
| agree - converting electricity into fuels is great, but only
| if said electricity does not have another use and would've
| been wasted otherwise.
| h0l0cube wrote:
| The capex in something, the opex is neglible, but the
| opportunity cost doesn't make sense until energy prices go
| very low or negative is some permanent fashion, or both
| fuel costs are very high and the switching to alternatives
| costs too much, or is even infeasible (e.g., air and space
| transport, shipping, steel production). A premium might
| make sense for specialist operators who want 'carbon
| neutral fuel', and have customers willing to pay for it.
| jfengel wrote:
| A fossil fuel tax would capture the externality that's
| currently not accounted for, and shift the viability of a
| project like this.
|
| All that's needed is the desire to avert much larger
| costs in the future. Or in other words, an absolute
| impossibility.
| herewulf wrote:
| > Making fuel for those by taking CO2 out of the atmosphere
| is a double win.
|
| It's just a single win because the CO2 is going right back
| into the atmosphere as the fuel is used (carbon neutral, not
| carbon negative). Still, a win is better than the loss that
| extracted fuels amount to.
| zemvpferreira wrote:
| I agree but you could still argue that any economic
| incentive to develop better carbon capture is another win.
| If captured fuel gets lots of use, maybe it will become
| cheap enough to manufacture that we will do so purely for
| environmental reasons.
| beojan wrote:
| You don't have to use all the fuel produced.
|
| Presumably some could be used to make plastics and
| everything else we make from oil. You could also bury some.
| Scaevolus wrote:
| Carbon-neutral combustion is a win over carbon-positive
| combustion of extracted coal/oil/gas.
| hnaccount_rng wrote:
| It's not entirely clear, that we can use e.g. deserts "for
| free". Changing the albedo of significant amounts of surface
| can have far reaching consequences. And unlike already
| populated areas (were this already happened), we don't really
| know what will happen there (probably until we try)
| spookie wrote:
| This is a good point. Urban areas are responsible in part
| for "global warming", just by their albedo. [1]
|
| [1] https://doi.org/10.1038/s41467-022-31558-z
| jfengel wrote:
| "In part" means 0.00107degC over the next century. That's
| less than a thousandth of the overall rise. So it's
| really not the top priority. Even assuming this
| technology increases it by a factor of 10 it's a massive
| net gain to displace fossil fuels.
| dmurray wrote:
| This is a cool project, but it's fair to say that 10 litres
| of petrol a day isn't sufficient scale to be described as
| "THE WORLD'S first industrial plant using solar heat to make
| fuels". It's a research prototype.
| conradev wrote:
| My measure of efficiency would at least incorporate capex
|
| It takes a non-zero amount of energy to build all of that
| energy-capturing equipment - question is, how much?
| ChuckMcM wrote:
| Sure, if you're doing a TCO analysis you figure out a
| deprecation schedule for your physical plant and your OpEx
| for the day to day operations. Of course the CapEx for
| "one" versus the CapEx per instance for "one thousand" will
| be quite different. Also how much site prep is needed, how
| much can be built offsite in a factory setting Etc. So a
| full economic analysis would incorporate all of that. Then
| price that against the price of fuel with the carbon and
| environmental externalities priced in, sure. That would
| give you a solid set of reasoning to say whether these
| systems are worse, similar to, or better than existing
| systems.
|
| If you _wait_ for all of that to be in place (versus
| risking capital today that might have been used for other
| things) then you risk dying from those aforementioned
| externalities of 'business as usual' (aka the do nothing
| hypothesis).
|
| John was, in my reading, defining "efficiency" to be
| turning the solar power available as electricity in the
| surface area of the plant into liquid fuel. And my response
| to that is always that the solar energy was going to hit
| that patch of ground anyway, and if you don't have the
| infrastructure to move it to where it is needed "right now"
| or store it, then its wasted. California is, today, having
| days where Solar and/or Wind generation is discarded
| because there are no customers demanding it. At some point
| (hopefully soon) we'll get better at dealing with this
| situation, and converting that "extra" power into syngas is
| a good use for it.
| almostnormal wrote:
| > That's maybe 10 liters a day. Seems low for the size of the
| installation. A liter of gasoline is about 10KWh. So if this
| thing gets 5 hours a day of full sunlight, it's putting out
| 2KW. That's like 5 standard solar panels.
|
| > Either I'm calculating this wrong or this is insanely
| inefficient.
|
| With your numbers: 10 l/day * 10 kWh/l / 5 h/day = 20 kW
| Animats wrote:
| Right. That's better. But there's more mirror area there than
| even 50 standard solar panels.
| herewulf wrote:
| It's a pilot plant. Its purpose is to develop, test, and
| demonstrate the technology. If successful then they can follow
| through with plans to build bigger plants that run at full
| capacity. They won't get the funding for the latter step
| without the former step first.
| swiftcoder wrote:
| It's a small-scale prototype of a much larger plant:
|
| > Synhelion already has plans to build a much larger plant in
| Spain in 2025 that will ramp production up to around 1,000 t/y.
| And beyond that, its ambition is to be manufacturing 1m t/y
| within a decade
| nashashmi wrote:
| They should come up with a way to turn leaves into oil. Send it
| down fractured wells and pump it out 10 years later.
| peter_d_sherman wrote:
| Related:
|
| Fischer-Tropsch process
|
| https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...
| carbonguy wrote:
| This concept is not _quite_ smoke and mirrors, since there 's
| nothing wrong with the science, but this article definitely reads
| more like a breathless press release than something truly ground-
| breaking. More notes below:
|
| > Synhelion was founded in 2016 as a spin-off from ETH Zurich,
| sparked by what the company founders describe as a crazy idea
| they had: what if they could reverse combustion and turn carbon
| dioxide and water back into fuel?
|
| This is not a "crazy idea", but rather a straightforward
| description of the chemistry involved. We call one implementation
| of this process "photosynthesis", but there are others.
|
| > The technology they've developed relies on four key components.
| Mirrors - known as heliostats - that track the sun to focus its
| energy on to a solar receiver. This in turn produces very high
| process heat at temperatures exceeding 1,500degC. This heat
| powers a thermochemical reactor that turns CO2, water and methane
| into syngas, which can be processed via Fischer-Tropsch into
| fuels.
|
| Again, this is well-understood industrial process chemistry -
| absolutely a good thing, in my opinion, but not new and sexy by
| any stretch.
|
| > And finally, a thermal store to release energy when the sun
| goes down to allow the solar-powered facility to operate around
| the clock.
|
| This actually IS new and interesting in this application (or at
| least, it is to me) - a shame that this isn't fleshed out more in
| the article. I tried to see if there was more about this aspect
| of their process on the Synhelion website, but their pages were
| loading slowly and I lost patience. Sorry, team.
|
| > The company says the design of its ultra-thin hexagonal mirrors
| are key to achieving such high process heats.
|
| Any physicists out there who have a speculation about why the
| thinness of the mirrors makes a difference here? My understanding
| is that the maximum temperature that mirrors can get you is
| limited by the surface temperature of the sun, rather than the
| mirrors themselves, but I'm certainly no expert on this point.
|
| > It uses an AI-based method involving drones to calibrate the
| mirrors 200 times faster compared to traditional techniques using
| cameras, Synhelion says. Precision is key to ensure the mirrors
| track the sun and efficiently reflect its light into a solar
| receiver at the top of a 20 m tall tower.
|
| This bit smells like trying to shoehorn in an application of "AI"
| where it's not really needed - what's the actual improvement
| using "drones and AI" over just pre-calculating a tracking curve
| based on latitude + time of day/year? Or just putting down twice
| as many mirrors and not bothering to make them track?
|
| > "... The inauguration of DAWN marks the beginning of the era of
| solar fuels - a turning point for sustainable transportation. Our
| founding dream of producing renewable fuels from solar energy is
| becoming a reality."
|
| This is hyperbole, as eg. Prometheus was doing this two years
| ago. Additionally, Synhelion will be hamstrung on growth as long
| as they depend on biomass methane as a feedstock, but they can
| solve that by buying methane from Terraform :)
| leetnewb wrote:
| Couple of points, but not a physicist or scientist.
|
| 1. I believe most existing concentrating solar plants operate
| below 1,000C. 1,500C might be well understood in producing
| syngas using other energy sources, but operating a CSP at that
| temperature is not. To the extent that a company is bringing a
| CSP plant to market with 1000+ temperature operation, that is
| novel.
|
| 2. Heliostat design seems like a core focus of improving CSP
| performance. A lot of research direction is on lowering the
| cost and complexity of deploying and maintaining the mirrors.
| See: https://www.nrel.gov/csp/solar-fields.html and
| https://www.energy.gov/eere/solar/heliocon
| fl7305 wrote:
| 1,500 C sounds like it's way past what any normal metals can
| handle?
|
| But in this case, maybe it is enough to have just a small
| part of the central reaction vessel handle 1,500 C? Maybe
| using ceramics?
|
| Or can you 3D print an Inconel chamber with builtin cooling
| channels that makes it possible for the Inconel surface to
| handle the incoming heat?
| leetnewb wrote:
| I think you nailed it on the ceramics. Pretty sure they are
| looking at falling ceramic particles in the tower to
| capture and transfer the concentrating solar.
| pfdietz wrote:
| Silicon carbide would work up to 1800 C. Various refractory
| oxide ceramics could also work.
|
| This whole approach needs direct sunlight, so it's not
| great for a place, like Europe, where it's often cloudy. It
| would be better for deserts, like in Chile, Namibia, or
| maybe the Arabian Peninsula.
| fl7305 wrote:
| It's not great for a production site. But for engineering
| tests, you can do a lot of stuff with no sun, and the
| occasional clear skies are used for sun testing.
| fl7305 wrote:
| >> And finally, a thermal store to release energy when the sun
| goes down to allow the solar-powered facility to operate around
| the clock.
|
| > This actually IS new and interesting in this application
|
| Yes, it's a nice thing to have. But it is a major research and
| engineering project just in itself. It is by no means a solved
| problem where you can buy a working solution from someone.
|
| > This bit smells like trying to shoehorn in an application of
| "AI" where it's not really needed - what's the actual
| improvement using "drones and AI" over just pre-calculating a
| tracking curve based on latitude + time of day/year? Or just
| putting down twice as many mirrors and not bothering to make
| them track?
|
| Open loop (just pre-calculate) is pretty inaccurate in a system
| like this. Especially over time as the mirror positioning
| degrades with accumulating inaccuracies.
|
| So there might be a business case for their AI drone
| calibration system. But just that part in itself is also a
| major undertaking that requires a significant investmet over a
| long time to make it a production system.
|
| "Just add more mirrors" sounds like a better business
| proposition, coupled with a much simpler autocalibration.
| Perhaps an off-center bullseye target where each mirror
| periodically aims itself, and a central vision system figures
| out the azimuth/elevation offsets?
|
| > This is hyperbole
|
| I agree in that I'd be very surprised if they ever get to the
| point of mass production.
|
| But I agree with the point that generating synthetic fuels from
| the sun in a 100% renewable way would be very significant.
|
| Sure, in 30-50 years electrical transportation might meet 99%
| of our needs. But we're not there yet.
| vixen99 wrote:
| > What if they could reverse combustion and turn carbon dioxide
| and water back into fuel?
|
| Humbling thought that the green weed outside your window is doing
| exactly that - plus, depending on the species, tens of thousands
| of variations on a carbon theme.
| phantom_wizard wrote:
| Seems like cool concept, basically it's just solar furnace with
| extra steps - to me it is a bit nonsense that it is placed in
| Germany because there are far better locations on a globe like
| Chile with 10 times more solar energy per m2.
|
| I am glad, however, that the idea of solar furnace is still being
| explored. Yesterday I was wondering if such installation could be
| put on a large ship vessel which would solve problem of year
| season. Also with our knowledge about tornado formations the ship
| could be put in places with max solar input.
| habibur wrote:
| Reading the article I get a feeling that it's more like proof of
| concept, than a economically feasible project, as there's no
| mention of costs.
| fl7305 wrote:
| In my view, it sounds like they're trying to tackle way too much
| at the same time.
|
| Just the core system that converts input chemicals and heat to a
| fuel is a major undertaking. Focus on that.
|
| Adding their own mirror system might be doable, but only if they
| use a well known and simple solution.
|
| Trying to add an "AI drone mirror autocalibration" is a major
| undertaking, enough to keep a medium sized company busy for a
| number of years.
|
| Likewise with the "solar energy storage system". Just run when
| the sun is shining, and produce as much fuel you can from that.
|
| If you have more incoming power from the sun than what you can
| produce fuel from, concentrate on solving that instead. Or just
| build something that is economical even if the mirror system is
| way oversized in order to always keep the fuel conversion busy.
| omneity wrote:
| At this feeble level of efficiency we're probably better off
| using the energy to split water into hydrogen or producing
| ammonia.
|
| It's a trade-off ultimately, either we get to use currently
| deployed ICE systems and feed them with this solar fuel, or
| deploy new engines to leverage hydrogen or ammonia based
| vehicles.
|
| Most probably better to bet on electricity storage tech catching
| up and just switch everything to full electric.
| jfengel wrote:
| There are some things that will be tricky to convert, notably
| airplanes. And it would be convenient to have synthetic gas for
| driving peaker plants on the occasions where they're needed.
|
| But yeah, ground transport needs to be electrified yesterday,
| and the grid upgraded to support it. That can be done
| incrementally, using existing technology.
| omneity wrote:
| In this case isn't biogas a much better option efficiency-
| wise?
| cduzz wrote:
| I think all of these approaches are not "or" but are
| instead "and" ...
|
| We need both PV solar and "let's get some heat" solar; we
| need LiFePO4 and nmc batteries; we probably even need to
| keep fossil fuels and biodiesel and other biogas.
|
| Every little incremental bit helps... It's a race between
| turning into venus and turning into mad max's thunderdome.
| mdale wrote:
| I like how mad Max thunderdome is a given at this point
| and the env work is just to prevent Venus #2
| gwright wrote:
| > the env work is just to prevent Venus #2
|
| There is no science-based predictions that climate change
| as we understand it today, will lead to Venus #2. That
| idea is just fodder for climate hysteria and sci-fi
| fantasy films.
| gwright wrote:
| > It's a race between turning into venus and turning into
| mad max's thunderdome.
|
| It is hard to tell how serious you are in that comment,
| but just in case, worrying about runaway greenhouse gas
| effect turning Earth into another Venus is climate
| hysteria.
|
| Poorly thought out energy policies due to climate
| hysteria have a good chance at creating considerable
| political unrest though (not sure about "thunderdome"
| level of unrest).
|
| Turns out when you restrict access to energy (e.g., by
| increasing its cost), people get upset.
| narrator wrote:
| Ammonia will likely not be used for cars and only be used for
| large industrial applications where there aren't any good
| alternatives like container ships because it's so toxic. For
| the same reason we don't have a make semiconductors at home
| with hydrogen fluoride kit, we won't have ammonia fuel in
| consumer oriented applications.
| alchemist1e9 wrote:
| Many years ago I remember seeing this same focused sunlight
| design being used to generate electricity directly from the heat.
| narrator wrote:
| "This heat powers a thermochemical reactor that turns CO2, water
| and methane into syngas"
|
| The methane has to come from biomass, so this isn't quite closing
| the loop here on a full solar only process. Pure CO2 and water to
| synfuels is still wildly energy inefficient.
| adolph wrote:
| When you say inefficient, do you mean that the process results
| in more entropy than work-producing fuel than another method of
| recomposing molecules into methane, such as biological
| processes?
| narrator wrote:
| If the Hysatas electrolyzer[1] is for real and scales up,
| making hydrogen is going to get way more efficient. They can
| make then make synfuels out of hydrogen for about a 40% loss.
| Eventually, they could put these electrolyzers at major
| airports and refuel hydrogen planes without having to move
| the hydrogen much. That's the big weakness of hydrogen is
| that it can't be moved around easily in pipelines. It can be
| stored in underground caverns under low pressure for cheap
| though.
|
| [1]https://hysata.com/news/hysatas-electrolyser-breaks-
| efficien...
| adolph wrote:
| Ok, I see two semi-related assertions now:
|
| >>> Pure CO2 and water to synfuels is still wildly energy
| inefficient.
|
| > If the Hysatas electrolyzer is for real and scales up,
| making hydrogen is going to get way more efficient.
|
| From the article, Synhelion has a thermal reactor now:
| solar radiation directed by heliostats into a thermal
| reactor that feeds a Fischer-Tropsch process. It seems
| difficult to establish relative efficiency of the whole to
| the Hysatas electrolyzer which is one component of a larger
| chain to capture and transmit energy to perform work.
|
| If I were to assume a similar story for Hysatas where
| photovoltaics feed electricity to electrolyze water and a
| whole new infrastructure for fuel is stood up: What measure
| would measure and demonstrate the relative efficiency
| between the two processes?
| narrator wrote:
| The finding the biomass to make the methane from is the
| non-scalable, energy intensive part. You have to collect
| the biomass, load it on to a truck, ship it around on a
| truck, and then unload it and dispose of it after it's
| depleted.
|
| If you only need air, electricity and water to make the
| synthetic fuel, that's going to be scalable to a
| civilizational level scale.
| szundi wrote:
| I'm looking forward to times when this silly technology kills all
| plants because no CO2 remained in the air but people need fuel
| LMSolar wrote:
| Several comments... Disclaimer, I work in this space.
|
| a) Surprised that on HN no one has commented on the similarities
| with Heliogen: https://www.heliogen.com/ This US-based company
| backed by Bill Gates and Bill Gross similarly focuses on high-
| temperature heliostat applications, e.g. green hydrogen and
| concrete etc. They even have similar hexagonal-mirror heliostats.
| b) Why these CSP startups so often focus on moon-shot 'super
| hard' applications like the above baffles me. There are LOTS of
| great applications for lower temperature solar thermal systems -
| which are much easier to build and operate. Our plastic-molding
| systems are just one example: http://lm.solar c) It's a little
| odd to be doing CSP in Germany - Heliostats need collimated light
| (non-diffuse light, e.g. light that casts a shadow) and Germany
| has pretty low DNI compared to, say, Morocco. I know the article
| says they plan to deploy commercially to Spain, but even a test
| system would be super hard to operate with frequent haze, high
| cloud layers, etc. To be clear, not saying PV-solar is
| impractical in Germany - PV can harvest diffuse light just fine.
|
| Funny that the photo of the solar tower / target in the article
| shows an overcast sky! Global Solar Atlas gives annual average
| DNI of @ 1000 kWh/M2/year at Julich, which is way low.
| https://globalsolaratlas.info/detail?c=50.922093,6.361102,11...
|
| I wish them luck, but there are likely more practical, impactful
| uses for CSP.
|
| PS Re the 'sunlight is free' comments... yes but if your process
| is very inefficient and/or requires a huge heliostat array then
| CapEx goes way up (which has to be financed = cost) and then you
| get into needing automated cleaning robots to keep your array
| working well (see Ivanpah -
| https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility ),
| etc.
|
| The cascading effects of moon-shot application => huge CSP system
| => problems (high CapEx, huge physical sites, permitting
| problems, need for automated cleaning etc) are exactly why we're
| working on industrial uses for SMALL heliostat arrays. And why
| grid-scale CSP (electric generation) systems generally get
| trounced by PV+battery systems.
| generuso wrote:
| If they get some traction, it might be interesting. It reminded
| me of another project which I have almost forgotten about.
|
| David Doty is a respected name in a narrow circle of nuclear
| magnetic resonance scientists for the hardware that his company
| builds [1]. At some point about a quarter century ago, he became
| obsessed with what he saw as an impending energy crisis, and
| started to look precisely into the technical nuances and
| economics of Fischer-Tropsch process. It seemed like a potential
| solution to turn excess of renewable energy into an energy-dense
| liquid fuel, which could then be distributed using the already
| existing infrastructure.
|
| Doty was always exceptionally meticulous in anything he did, and
| so he went with a fine comb to find and eliminate inefficiencies
| in the fuel synthesis process, wherever it was physically
| possible. He funded a small team working on this, and they came
| up with some improvements [2] which they have patented, presented
| at conferences, etc. But despite all this work the economics of
| the process was still not favorable.
|
| [1] https://dotynmr.com/ [2] http://www.dotyenergy.com/
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