Could mirrors and steam be a cheaper energy source than nuclear?

Posted: January 5, 2016 by tallbloke in Energy

Solar collector powering stirling engine – image from Wikipedia.

H/T to Nigel Reading of Asynsis design for a pointer to an interesting paper from 2010 by Derek Abbott: “Keeping the energy debate clean: How do we supply the world’s energy needs?” The paper discusses  the scenario where fossil fuels are eventually becoming harder to extract and/or we need to conserve them for non-fuel use such as plastics production. Looking at the alternatives, Abbott concludes that solar plus liquid hydrogen is the way to go. Rather than solar PV, which uses lots of arsenic, he recommends dish collectors heating Stirling or Rankine engines, which have a longer life despite higher initial costs. Energy storage for night-time power would be via electrolysis of hydrogen from water. The spin-off benefit is liquid hydrogen as an automotive fuel.

On his calculation, it can be done at less expense than nuclear, when factoring in decommissioning costs and the costs of running vehicles on batteries charged by nuclear generated electricity. The paper takes under consideration long term energy strategy, calculating water usage and considering economies of scale.  A worthwhile read.

Full paper


  1. Adam Gallon says:

    Certainly we’re not short of water currently (At least here in the UK).
    However, I’d suggest that sunshine is something we tend to lack.

  2. oldbrew says:

    The world is using over 95,000,000 barrels of oil a day.

    Tell us where all the mirror installations would be placed to match that 😉

    It’s not scaleable IMO – you’d have to be out of options to want to try it.
    Can’t see the Russians being impressed.

  3. tallbloke says:

    Yeah, it’s a solution for low latitude desert areas, exporting the generated energy to water sources for the production of liquefied hydrogen, which can then be transported to point of need. Not a cheap fix, but a longer term vision for the time when oil and coal are being preserved for other uses. The thing I found more compelling was the argument about long term availability, and the sheer amount of energy available from the Sun compared to other sources.

    The calc is ~10,000 4 x 4 km arrays worldwide, requiring the production of a solar dish and Stirling engine at about the same rate as cars are being made for the next 20 years.

  4. graphicconception says:

    I once did a back of an envelope calculation for the USA energy supply. They would need about 40,000 of their facilities at Ivanpah to supply their current energy needs. Each one covers about 5 square miles.

    If I divide that by 5 to get an approximate figure for the UK we would need 40,000 square miles of mirrors installing or 8,000 installations. Where would we put them? In fact, it is worse than that because we would need even more because of the lack of sunlight in the UK.

    It took about 5 years to build one so we have a building project that will require 40,000 years of construction work.

    It would be interesting to calculate how much hydrogen needed to be stored for night time use as well. Another question is: Could we make such large tanks that could entrap the small H2 molecule. It has a habit of seeping out of “closed” containers.

    They say that sunlight is free but so is coal. It is the method of converting it from where it is into where it needs to be that creates the cost.

    Then you need to factor in the replacement costs. With 40,000 square miles of mirrors to service it would be like the painting the Forth Bridge on steroids. With a lifespan of 40 years you would need to replace 1,000 square miles of mirrors each year.

  5. Fanakapan says:

    Production aint the problem, its Storage.

    Until such time as there is a breakthrough in the storage of electricity, most of these suns energy capture ideas are nothing more than Boondoggles 🙂

    As for ‘Fossil’ fuels running out, I suppose its logical they’d have to run out at some point. But all the reasoning at this point is based upon the idea that they are the result of the decay of virtually unimaginable quantities of micro organisms and such. If one starts to admit the possibility that Abiotic Oil could exist, then the picture assumes a different angle. It certainly would be a very different picture from the one of depletion in 20 years time that seems to have been running for the last 60 years or more ?

    Obviously there’ll be many who will consign to the dustbin any theory that hydrocarbons could not be possibly be anything other than the result of decaying organisms. And I have to admit to some scepticism myself, but considering that Tectonic Theory was not accepted until 1964, its clear that the last word on oil and gas may not yet have been written ?

    Hydrogen is the most common element in the universe, and carbon is the 9th most common, couple that with Saturns moon Titan, seemingly producing vast quantities of hydrocarbons despite having been devoid of life since its formation, and it starts to look like a safe bet that ‘Fossil’ fuels will be playing a huge part in civilisation for many generations to come 🙂

  6. Konrad says:

    The problem with solar remains storage and distribution of energy. “Hydrogen from electrolysis” is not an answer. Today only around 2% of hydrogen used in industrial processes is from electrolysis, the rest is produced from hydrocarbons. The reason is electrolysis of pure water is difficult due to the poor conductivity of fresh water. Acids, bases or salts need to be added to improve efficiency and this leads to unwanted by products and choking of electrodes etc.

    There is however one simple solar system that works well for storable baseload power – hydro electricity. The infrastructure costs are low, as all that is needed are dams and turbines. The solar collector is free and covers 71% of the planet’s surface. Sadly environmentalists are strongly opposed to dams.

  7. tallbloke says:

    There’s a more easily digestible summary here:
    “Abbott calculates that, in order to supply the world’s energy needs, the footprint of such a system with pessimistic assumptions would be equivalent to a plot of land of about 1250 km by 1250 km – about 8% of the land area of the hot deserts of the world. With less pessimistic assumptions, the land area could be reduced to 500 km by 500 km, corresponding to 1.7 billion solar dishes that are each 10 meters wide.”

    Let’s go with 1000km x 1000km, a nice round million square km. Or 62,500 4km by 4km sites, each containing 128,000 solar collectors, linked to a cabling system for taking HVDC to a coast where enough water can be obtained for the hydrogen production.

    Compare that with the cost of building enough nukes to power the world, if there was enough fuel availability.

  8. ntesdorf says:

    ‘Environmentalists’ are strongly opposed to dams and hydro-power, nuclear power, coal, lignite, oil, gas,and all other sensible ideas and sources of power..

  9. tallbloke says:

    I think this guy is coming at it from a different angle. More engineering than environmentalist. He’s saying, “OK, what is the total power available from different sources in the long term? Shouldn’t we plan to develop economies of scale in those which can keep us going longterm? That’s an argument worthy of consideration in my view.

  10. John Silver says:

    Not exactly a new idea, John Ericsson did it 1872:

  11. tallbloke says:

    Nice device. Stirling engines have come a long way since then.

    “Tessara Solar completed the 1.5 MW Maricopa Solar power plant in Peoria, Arizona, just outside Phoenix. The power plant is comprised of 60 SES SunCatchers.” The SunCatcher is described as “a large, tracking, concentrating solar power (CSP) dish collector that generates 25 kilowatts (kW) of electricity in full sun”. Each of the 38-foot-diameter collectors contains over 300 curved mirrors.

    That’s 232W/m^2. With the 62,500 facilities mentioned earlier, that’s 2 million gigawatts in sunshine. So 1/3 of that worldwide constantly, allowing for night and cloud (in deserts) is 666 TeraWatts.

    That’s 40 times current world electricity consumption, so plenty of room for the inefficiencies of Hydrogen production and automotive use.

    As a bonus, the 38 foot suncatchers don’t get hot enough to bother birds either.

  12. tallbloke says:

    Fanakapan: Until such time as there is a breakthrough in the storage of electricity, most of these suns energy capture ideas are nothing more than Boondoggles

    I suppose it’s partly a question of what you want to run your car on if Saudi Arabia and Iran go to war, and the Ruskies can get a better price from China than we can afford. Personally, liquefied hydrogen in a nice cylinder seems a better option than a pile of pig crap in a bag on the roof.

    Fracking for natgas is fine too, but it might only last a few decades. The point of this thread, is to ask what we’ll do in the longterm. You may be right about unlimited abiotic oil. There again, you may not…

  13. You know that if I’d put in a paper like the one cited for my final year “thesis”, I’d have been failed. That was 1982.

    In 1981/1982 our “Energy” class went to visit an experimental site (then operated by SERIWA Solar Energy Research Institute of Western Australia) to see what was leading edge and to understand the necessities/problems of implementation. One of the units was solar-thermal with a Stirling engine. While the engine was in itself the most-efficient, it delivered very little usable power because the thermal cycle wasn’t hot enough; and it depended upon the sun. Those who studied thermodynamics will appreciate the limits of efficiency as described by the Carnot cycle; which is determined by the extremes of temperature ofthe hot and cold “sides” of the engine.

    The take-home message was that solar was a niche “product”, suited more to remote area power systems where the availability/transport of other energy carriers was prohibitive. e.g. the Moon. 😉

    The updated versions still depend upon the sun. Insolation is both diffuse and variable. There is the misconception that deserts always enjoy clear skies. That’s far from true; it simply doesn’t rain a lot. Which brings us to the problem of dust. I’m unfamiliar with the dust in deserts of other continents but here in Australia, it’s impossible to keep the dust off anything for any significant time. Further; the dust sticks and does not get blows away. It builds up unless removed mechanically by e.g. brushes and water.

    The author draws conclusions based on a myriad of assumptions; such as being able to harvest 10% of the insolation of desert regions. Even for solar-thermal, that’s wishful thinking because the energy has to be transported to consumers who, by and large, live very, very far away from deserts. There aren’t just conversion and transmission losses to consider; there’s the matter of securing the rights to build transmission lines; their maintenance and assurance of their security.

    The author also hopes that hydrogen production during daylight hours will produce enough hydrogen to allow energ production when the sun’s not out or bright enough. [insert footage of roof of the fuel storage facility roof getting blown off by a hydrogen explosion at Fukushima.]

    His description of Gen IV reactors is so bad that it’s not even wrong. It’s worse than Wikipedia’s.

    His use of Hubbert Curves to under-pin the imminent exhaustion of fossil fuel resources is more appropriate to the level of (oil and gas) understanding of the 1930’s to 1970’s. We can tell that oil and gas compounds form on other planets in our solar system; without the need for “fossils”.

    In his quest for a “sustainable” energy solution, the author appears to have ventured far outside of his small areas of expertise.

  14. EternalOptimist says:

    I was down in the Kalahari last September and managed to see the spectacular Solar1.
    I also managed to get a picture at sunrise, which happened to be just as the moon was setting

    I had to try half a dozen times to get the photo, because the moon was obscured by cloud.
    You get a lot of cloud, even in the desert, at all times of day

  15. Graeme No.3 says:

    The Stirling Solar farm he features went bankrupt in 2011.

    As a comment, the high efficiency achieved of 31% conversion was over an hour early on one winter morning at minus 8℃, with “crystal clear” skies. If the sky is dusty then output drops dramatically, so all they need is a dry, non dusty desert without vegetation and with a good supply of fresh water for cleaning the mirrors.

  16. p.g.sharrow says:

    Some of this is stuff I worked out in the mid 1970s. However the size of the assumed needed reflectors as well as land amounts is much too small for future need energy supplies. The projected increase in electrical generation requirements from 1975 to 2025 would have required 800 square miles/1200sqKm of reflector surface just for the needed increase. Even if sunlight is free, construction and maintenance are not! Every array must be cleaned every week and damage from the environment will require constant attention.
    Hydrogen conversion for storage of energy storage is a very wasteful use of the energy generated. Unbelievably wasteful! Solar energy used to GROW liquid fuels is MUCH more efficient.
    My conclusion after 6 years of exploring the concept of terrestrial solar energy generation was that it was at best, a doable solution if nothing else was available. Unlike others, I had to devise solutions that would work under conditions on the ground, that real people could do, in a cost effective manner.
    To make his solution real, Derek Abbott requires that this conversion be made mandatory! After a litany of Assumptions to make this look doable. Ecoloon BS….pg

  17. michael hart says:

    A sense of responsibility prevents me from saying how I would go about improving the extraction of Uranium from seawater, but it’s not a hugely challenging technical problem. I don’t think we’ll ever run out.

  18. tchannon says:

    All these schemes are optimistic. Actual demand is much greater. Costs are much higher than assumed. Tech issues anyway.

    There is no alternative to very large scale nuclear where by scale I mean huge plants. This ends with too cheap to meter for many cases. Perhaps I need too explain why, what is blinkered.

    A current long term crazy of most humans is silently buying the protestant ethic of shortage. Hence for example the ridiculous problems with solar and wind… only a problem because of the system operation in permanent shortage. Whereas a sufficient system would merely absorb the energy into intermittent processes.

    Problems are mental.

  19. oldbrew says:

    In Abu Dhabi they have to clean all the solar mirrors every THREE days.
    Lots of water plus fuel for the trucks needed.

    ‘How Do You Clean 250 Thousand Solar Thermal Mirrors? Trucks With Robot Arms!’

    Quote: ‘there isn’t much of a difference in output between clean and somewhat dirty mirrors, but when they get extremely dusty (which happens quickly in the windy desert of the UAE) and the reflectivity drops very low the efficiency comes down dramatically.’

    And nuclear could be about to get cheaper.

    ‘Geim and his colleagues at the University of Manchester have found that graphene filters are effective at cleaning up the nuclear waste produced at nuclear power plants. This application could make one of the most costly and complicated aspects of nuclear power generation ten times less energy intensive and therefore much more cost effective.’

  20. tom0mason says:

    “Energy storage for night-time power would be via electrolysis of hydrogen from water. The spin-off benefit is liquid hydrogen as an automotive fuel.”
    Hydrogen embrittlement of all components being allowed for, I assume.

  21. ivan says:

    There are just too many problems with this idea to use it for mass base load power. Efficiency is very low, the mirrors have to be absolutely clean even to get that low efficiency. There must be clear sky or again the efficiency drops. If you put these things in desert areas the cost of running them becomes prohibitive, it is rather expensive to pump water over very long distances and the conversion of water to hydrogen is not very efficient either.

    The moment that someone mentions transporting hydrogen over long distances and its usage by the general public everyone should run a mile.

    Hydrogen has this very nasty habit of finding the weak spot in any container and using it to escape to the atmosphere. Fine if you are NASA and understand the risks, no go if you are Joe sixpak filling his car.

    Nuclear power could be very competitive IF, and only if, the authorities dumped the about 75% of regulations that are completely unnecessary but were generated as a knee-jerk response to the very vocal anti nuclear faction of the greens.

  22. Graeme No.3 says:

    Agreed. The conversion to hydrogen via the continuous process is below 82%. That translates into a 22% increase in cost ignoring transmission losses etc. But this process will be more intermittent and MIGHT make 60% efficient, although I would expect less than 48%, so the cost doubles.
    Visions of liquid hydrogen fueled vehicles look less attractive when you realise that hydrogen in a internal combustion engine has a knock value of 60 (less efficient) and that the more efficient hydrogen fuel cells require a separate feed of oxygen and mostly weigh multiple tons for the required output.
    By chaining these inefficiencies the cost sky-rockets (no pun intended).
    There is also the little matter of dispensing liquid hydrogen at retail outlets. Did someone mention it burns? That is almost as much damage as the un-ignited liquid does on skin.

  23. Nothing new about solar thermal stations see here I visited the station just before it was shut the first time and connected to Broken Hill. Wiki does not give the full story. The original steam arrangement did not work (corrosion, cracking to due uneven heating, poor design etc) so they converted the solar heating with a thermal fluid which then created steam in an heat exchanger- this had it problems with seal breakdowns and leak of thermal fluid (even a fire) Battery charging never worked satisfactorily so the diesel was run frequently leading to breakdown of the diesel. The local motel installed their own diesel (slightly larger than the power station diesel) because the blackouts were so frequent and sold power to the station. At my visit there were 4 employees (there were more previously) -a mechanic, an electrician -both on contract, the supervisor and an offsider. At the time of the visit the supervisor was cleaning the dishes which had to be done once per week and took about one day for all the dishes -most of that time the diesel was running as for safety sections of the dishes had to be taken off line. A power line was built connecting it to the large diesel power station at Broken Hill and the station shut in 1996
    The Photovoltaic station only lasted about 3 years to 2004. It was put in as a trial to augment the Broken Hill power. But it gave no savings, was a maintenance headache, and a problem for control. When Broken Hill and White Cliffs were both connected to the NSW electricity grid the Photovoltaic station was shut down -an experiment but operational failure. Solar power makes no sense and is not free.

  24. A C Osborn says:

    Replacement for Fossil Fuels, when they get scarce and expensive, 2 words
    Methane Hydrates.

    Ask the Japanese.

  25. oldbrew says:

    ACO: methane hydrates are at the bottom of the sea – what are the recovery costs?

  26. jim says:

    A lot the arguments. Seem to me its still simpler to create a local geothermal steam system. Drill down far enough, for the compressed mass of the earth, to heat the fluid used, to create a circulation, thru a pump/fan hooked to a generator, and scale up. Never had enough money to try it. But, sounds so easy. I believe I read of those systems, in the 60’s. Never heard of it after, so must have worked and been low cost. And simple to produce.

  27. A C Osborn says:

    Oldbrew, like I said ask the Japanese, they have done it and reckon to have it in production in about 5 years.

    Jim, they have tried it in various places with little success, but Iceland ( which is Volcanic) have it working very well.

  28. oldbrew says:

    The future is here: US fracking industry now exporting oil and gas to all parts.

    Japan: wait and see. Clathrate research is ongoing.

  29. p.g.sharrow says:

    Geothermal Energy:
    Geothermal energy production has to work in the real world without government backing, so it is generally small size and poorly financed. Most of the attempts that I know of are being blocked from connection by the regional distributors unless they sign contracts to sell power to the distributors at the lowest rate and under very restricted conditions. There are a few successful operations that have been running for many years, so we know it works within real world economic conditions. The costs and engineering needs are well understood. Generally the best resources are not where you need them, but the largest road block to Geothermal Energy use is politically inspired NIMBY regulations…pg

  30. Curious George says:

    PEORIA, AZ (AP) April 3, 2012 – Hoping to draw cash along with sunrays, Peoria’s SunCatcher Project built near the Agua Fria power plant is on the selling block. The Salt River Project was partnered with Scottsdale-based Stirling Energy Systems on the Peoria SunCatcher project until Stirling went bankrupt last fall.

    Large, mirrored dishes focused sunlight to an engine to produce power but it came at a premium.

    SRP spokesman Scott Harelson says there are cheaper ways to capture solar energy now. The main parts supplier for the project also filed bankruptcy.

    The SunCatcher auction is scheduled for April 17. Among the expected bidders will be scrap-metal dealers.

  31. tallbloke says:

    Anyone who picked up a 28kw stirling engine for scrap price got a good deal. Could make a nice quiet gas fired generator for a small hamlet of houses with that. 🙂

  32. Berényi Péter says:

    Could mirrors and steam be a cheaper energy source than nuclear?

    Definitely not.

    Thorium &. Uranium in one ton of ordinary granite, the default stuff continents are made of, contains as much retrievable energy as 50 tons of coal.

    The way to do it is by molten salt reactors.

    – Inherently safe design (safety by passive components and the strong negative temperature coefficient of reactivity of some designs).
    – Operating at a low pressure improves safety and simplifies the design
    – In theory a full recycle system can be much cleaner: the discharge wastes after chemical separation are predominantly fission products, most of which have relatively short half lives compared to longer-lived actinide wastes. This can result in a significant reduction in the containment period in a geologic repository (300 years vs. tens of thousands of years).
    – The fuel’s liquid phase is adequate for pyroprocessing for separation of fission products. This may have advantages over conventional reprocessing, though much development is still needed.
    – There is no need for fuel rod manufacturing
    – Some designs can “burn” problematic transuranic elements from traditional solid-fuel nuclear reactors.
    – An MSR can react to load changes in less than 60 seconds (unlike “traditional” solid-fuel nuclear power plants that suffer from xenon poisoning).
    – Molten salt reactors can run at high temperatures, yielding high efficiencies to produce electricity.
    Some MSRs can offer a high “specific power”, that is high power at a low mass. This was demonstrated by the ARE, the aircraft reactor experiment.
    – A possibly good neutron economy makes the MSR attractive for the neutron poor thorium fuel cycle.
    – LWR’s (and most other solid-fuel reactors) have no clean “off switch”, but once the initial criticality is overcome, an MSR is comparatively easy and fast to turn on and off. For example, it is said that the researchers would “turn off the Molten-Salt Reactor Experiment for the weekend”. At a minimum, the reactor needs enough energy to re-melt the salt and engage the pumps.

    Almost all the energy in fissionable &. fertile materials can be extracted, leaving a hundred times less waste behind for the same energy output, than in “conventional” nuclear plants, which are actually pretty dangerous Cold War Plutonium factories, with some energy as a by-product. Also, due to high boiling point of molten salt (~1400°C), it can be run at a high temperature (~800°C) and low pressure. At this temperature one does not need water, just a neutral gas like Nitrogen as a working fluid in gas turbines, which is good, because water can get real nasty at high temperature. One can also drive a chemical plant directly using this heat source, which makes synthetic fuels and much else a piece of cake.

    It’s a no-brainer, really.

  33. Wayne Job says:

    We have plenty of uranium in OZ we just have a green problem.

  34. E.M.Smith says:

    We have an effectively unlimited supply of uranium at reasonable prices (just not cheaper than land sources) so solar isn’t needed for a few hundred thousand years…

    Oh, and when an article says we need to save petroleum to make plastics and chemicals, you know immediately it is GreenWash and / or ignorant. Chemicals and plastics can be made from ANY carbon source. Currently natural gas is preferred, but coal was used befor oil. Also used are plants and even garbage.

    Yes, it is nice to know we have huge amounts of sunshine. We also have lots of rocks and salt water. A nice life can but made with rock homes, fishing, and solar heating… but I’d rather have a choice including lamb chops, a fast car, and electric lights…

    There simply is no shortage of resources nor of energy, nor will there ever be. There can only be a shortage of vision and political will.

  35. steverichards1984 says:

    I think the problem with Thorium is materials science.

    Containing the hot liquid as it trundles around the plant and

    by-product separation.

    I understand that there are no industrial scale separation processes to handle Thorium.
    It all works in a test tube but not at scale.

    I suspect it will consume billions to get the science safely working, just like uranium processing did.

  36. tallbloke says:

    Thorium not ready for prime time but Chinese and Norwegians have test reactors.
    Uranium is viable but decommissioning is tough due to (over?)regulation.
    Nuclear cars are a no-no because terrorists.
    Battery cars charged with nuclear electricity are a no-no because lithium prices.
    Plenty of oil but no-one knows how difficult the Iranians and Saudis are going to make things.
    Some decades of easy access shale gas.
    Solar PV is getting cheaper but nasty ingredients, distances of transmission from sunny places and cleaning are issues.

  37. dscott says:

    IF MSR (Molten Salt Reactors) are so good then are there any examples of commercially operated ones? None to date from my searches.

    Molten Salt Nuclear Reactors: Part Of America’s Long-Term Energy Future?

    The main problem with MSR technology at this point are #1 the Regulators (government bureaucrats) and #2 a corrosion issue posed by the salts. Sadly, because of issue #1, the Chinese will be the first to develop a viable MSR given their risk tolerance is governed by the potential reward. That is why Thorium Reactors are a pipe dream in the West, you might as well be selling limitless electricity from fusion.

  38. Asynsis says:

    Thanks for starting this thread off the bat from my earlier comment on another thread.
    So how about alternative Fusion like the Stellerator in Germany, Lockheed Martin or Focus Fusion’s efforts?
    They’re also “solar” in a sense – with the most efficient of all being the focus variety that generates current directly – without recourse to steam turbines.

  39. tallbloke says:

    Welcome back Nigel, and thanks for starting a lively debate.

    It has to be said that large scale solar of the big central tower design hasn’t worked out well. Ivanpah is having to burn lots of gas. It fries birds in mid-flight, and the taxpayer is groaning. Smaller dishes and Stirlings don’t look economically viable or physically realistic in location and maintenance terms.

    So, fusion. Hmmm.

    Always seems to be “30 years away, more research money needed”. I’m not saying we shouldn’t keep trying, but no-one has ever observed two protons fuse yet so far as I know. So it’s not a bet we should rely on.

    Fortunately, there’s no shortage of oil gas or coal, so we have plenty of time to invent something really smart. And as a bonus, the co2 emissions seem to be doing more good than harm, woody biomass is up and the deserts are getting smaller. Temperature is stable for the last two decades, and if co2 does cause any more warming than Stephen Schneider was telling us back in 1971, it’ll help offset the coming century of low solar activity.

    Rasool and Schneider 1971

  40. Curious George says:

    Asynsis: I could not find how the focus variety generates current directly – without recourse to steam turbines. Could you please provide a link?

  41. ivan says:

    Since molten salt reactors have been mentioned the UK was once in the forefront of the research, see:

    Something else we no longer do in the realm of hard science and engineering (I doubt it could be done today because of the ‘universities’ emphasis on the soft sciences and no engineering)

  42. John PAK says:

    My father looked at MSR for the UKAEA in the 1980s and concluded that the molten salt and the thorium daughter products would be too expensive to reprocess. The chemists said it would be a nightmare to separate out the useful products from the molten salt.
    The preferred option was a very high temperature, liquid helium cooled, modular reactor akin to the pebble-bed design in Germany.
    Unfortunately, Chernobyl changed the minds of most politicians and the UKAEA’s brilliant design team was doomed.

  43. Asynsis says:

    New Sterling design – also more directly generating current, thermo-acousticly:
    Focus Fusion link:
    The problem isn’t just CO2, it’s increasingly becoming Methane:

  44. Asynsis says:

    A sterling Stirling Engine design, even. 🙂

  45. tallbloke says:

    Nice! I love Stirling engines.

    One of those would tick over nicely on the flue gases from my woodburner.

  46. ivan says:

    tallbloke, that vid is long on hype but very short on real details.

    I love the magic bit where electricity appears from thin air – if only it were so. If they want anyone to really evaluate what they have done they should publish technical details and the figures from their test rig. When people don’t publish details, my first reaction is ‘scam’, sorry.

  47. oldbrew says:

    Asynsis says: ‘The problem isn’t just CO2, it’s increasingly becoming Methane’


    ‘methane (CH4) has narrow absorption bands at 3.3 microns and 7.5 microns (the red lines). CH4 is 20 times more effective an absorber than CO2 – in those bands. However, CH4 is only 0.00017% (1.7 parts per million) of the atmosphere. Moreover, both of its bands occur at wavelengths where H2O is already absorbing substantially. Hence, any radiation that CH4 might absorb has already been absorbed by H2O. The ratio of the percentages of water to methane is such that the effects of CH4 are completely masked by H2O. The amount of CH4 must increase 100-fold to make it comparable to H2O.

    Because of that, methane is irrelevant as a greenhouse gas. The high per-molecule absorption cross section of CH4 makes no difference at all in our real atmosphere. [bold added]

    Unfortunately, this numerical reality is overlooked by most people.’

  48. tallbloke says:

    Ivan, the linear alternator tech is already happily generating a kw of electricity in thousands of sunpower Stirling engines inside domestic CHP boilers around the world. Commercial sensitivity prevents full disclosure of the details, but the principle and some home-brew stuff is easily found on youtube.

  49. ivan says:


    My point, which I didn’t get across clearly, is that there does not appear to be any connection between the free floating pistons shown and any electrical generator, linear or otherwise.

    I do know about linear alternators having built one myself just to see how they worked and to see if the permanent magnets could be replaced as in the brush-less rotating type and can well appreciate how they would work in a Stirling engine. Unfortunately the vid missed out on that bit of information as well as any measurements on their demonstration rig.

  50. tallbloke says:

    Yes, it’s a simple (nicely done) schematic showing their Stirling cycle rather than an in-depth look at all the tech. But the linear alternators on the Sunpower design below are also on a ‘free piston’ engine, so I don’t doubt they can make it work as advertised.

  51. Gail Combs says:

    P.G. says “… the largest road block to Geothermal Energy use is politically inspired NIMBY regulations

    You are correct. I have a backhoe and could digg the hole to and lay the pipe for geo thermal home heating/cooling but I am not ALLOWED TO. Thus the cost is tripple what conventional HAAC would be.

  52. jim says:

    On, sorry. Was down southern Missouri. Catching the evening news. There was an interesting commercial from one of the well known names i n home heating and cooling. Showing them doing some of the geothermal home temperature stabilization techniques. Straight out of the 1980’s conservation techniques handbook. That’s was interesting. But in the handbook, they also had, a vertical system, going down about 200 feet, for warming a liquid filled rockbed underfloor system. And another system doing the heating and cooling with dry air. Off a radiator.

  53. gallopingcamel says:

    No matter how you implement it solar power is not scaleable.

    While it may make sense to put solar panels on your roof where I live (in Florida) industrial scale solar whether PV or CSP simply takes up too much real estate. Do the arithmentic and you will agree:

  54. p.g.sharrow says:

    I have always thought that the Fixed Frequency reciprocating motor-generator was a natural. Wished I could buy some of them to power my farm… pg