OT: "Science" on the other side of the pond

Great.

Sometimes the sun doesn't shine on consecutive days here. Perhaps your situation is different.

Sylvia.

Certainly there is investment involved - but a viable long-term energy storage is the only way to make unstable energy sources (such as solar, wind or wave power) practical.

At the moment, these energy sources are worse than useless - they don't provide the power when power is needed, and they don't have the long-term supply stability to provide alternatives to traditional power sources. They actually cost twice - the grid and other power sources need to burn off the excess generated power when the sun is shining or the wind is blowing, and these other power sources need to cover the drop when the renewable sources are not available. And apart from hydroelectric, most traditional power sources cannot easily and efficiently ramp up or down in production capacity.

The use of molten salt or other storage mechanisms helps a bit, but not enough - they can supply power overnight from a solar station, but can't help with a couple of cloudy days.

But if the renewable power were turned into ethanol, you have a safe, stable, portable and flexible energy storage that can be stored indefinitely, or transported to the end user using existing infrastructure. It can also be used directly in cars without any change (and since the CO2 is recycled, the old polluting car suddenly becomes clean and environmentally friendly).

So yes, this would cost money - but the alternatives are to spend money on useless renewable sources to appease ignorant environmentalists, to continue with fossil fuels to appease climate denialists (who are /all/ ignorant), or to invest in a world-wide grid in order to balance renewable sources properly.

(Personally, I think that for the medium and long-term, thorium reactors are the way forward - but that too costs money.)

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They don't. It's trivial to draw less current from a solar cell at a higher voltage than the one that delivers optimal power output. I recently sat th rough a lecture from a solar cell system supplier which was mainly boasting about how his gear could do that automatically and without human intervent ion.

Gas turbine systems are pretty quick, and have been added to networks to do precisely this job. Pumped storage systems are better, but harder to set u p.

Geographical diversity helps there. But any solar power system has to be so mewhat over-sized - like any other generating system - to cope with improba ble peaks in loading, and failures at other generating plants.

There are plenty of perfectly useful renewable power sources around. IIRR w indpower is now competitive with power generated by burning fossil carbon, and another push on production volume for solar cells would get them into t he same happy state.

Denmark already gets 39% of it's electricity from wind turbines.

I don't think that anybody has run the numbers for a world-wide grid. Germa ny is talking about building itself solar power plants in the Sahara and sh ipping the power north across the Mediterranean.

Nobody seems to be talking about high-temperature super-conductor transmiss ion links. Presumably this is eventually going to be practical.

If you can work out what to do with the nuclear waste. There are all sorts of schemes that ought to work, but no places that seem willing to accommoda te a nuclear waste repository. It's thus a political rather than a technica l problem, but one that remains unsolved. And what look like technically ad equate solutions don't always turn out to be adequate when reduced to pract ice.

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Bill Sloman, Sydney

like, say, a sack barrow? you still have to walk, but the wheels carry the battery.

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it takes lots of water to make ethanol. where doe that come from?

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Australia is not much less extensive as the US in this respect. It's 4030km form one side to the other, where the US is 4500km.

That doesn't make any difference to the technical questions. More concentra ted populations are easier to serve, but you haven't addressed that.

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Why would that be a problem? Existing power generating stations tend to be pretty big too.

It doesn't stop a lot of home-owners from putting them up.

It's not difficult - or expensive - to insulate hot water tanks to get a th ermal time constant of several days. Shower and dishwasher timing then beco mes less important. If you build the super-insulated hot water tanks into t he body of the house, it gets even easier.

Skype seems to offer practical video conferencing. People do need some real face-to-face contact, but probably not every day.

Wouldn't suit me. I like to look at the stuff I'm buying - and sometimes ne ed to touch it. Avocados tend to need careful inspection.

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You miss the point. Pump-generator sets are big and expensive. Molten tanks are aren't all that big (though big enough that insulating them to a time constant of couple of days isn't exactly difficult). The point is that the energy is stored before it gets converted to electricity, and you don't hav e to pay for the extra pump-generator sets to store and recover the energy.

The data is out there. Building a test rig might be fun, but it would be a waste of time. No moving parts solar cell set-ups have dominated the low en d of the remote energy market for a long time now.

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Bill Sloman, Sydney

Pick your desert environment more carefully, and have a couple of solar tower set-ups far enough apart that only one of them is going to be shaded. And you can scale up the tank of molten salt so that it stays hot for a couple of days.

It's a soluble problem.

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Bill Sloman, Sydney

ning fossil carbon, but that's because the generating stations don't have t o pay the price they ought to for the privilege of dumping CO2 into the atm osphere.

So wake me up when solar power is less expensive than burning fossil fuels. We have made a lot of progress in the last 200 years. We have enough kn own fossil fuels to last another 200 years. I have faith that we will make more progress in the next 200 years. But until solar power is cheaper tha n fossil fuels , nothing significant is going to happen.

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eople are playing around with photosynthesis, and one of the scheme produce s hydrogen gas from water and sunlight - inefficiently, of course. It's yea rs since I saw the abstract and I've got no idea where I saw it.

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quite a lot of oil from coal during WW2, and it sounds as if somebody has r evived the process to work with biomass rather than coal. The "70%" refers to the process as a whole, which leaves room for a lot of fudging.

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adds any new CO2 capture,

They did, and also thought 70% energy conversion efficiency in producing the fuel meant the syn-diesel would triple their cars' gas mileage.

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. The 70% claimed is remarkably good, and most likely based on a misconcept ion.

That's 70% claimed for the whole process, so the electrolysis component would have to be better still. Super-efficient electrolysis would have all sorts of power storage / renewable fuel applications, hence my query.

Cheers, James Arthur

If each of these towers can meet all the power requirements, then by implementing two, you've already doubled the underlying cost even before power transport is considered.

Just how far from the power consumers should these towers be, and how far from each other? Transporting power over long distances is very expensive, and the losses mount up.

How do you know that these two towers won't simultaneously be clouded out either because of a large weather system, or because of two separate weather systems? Should we perhaps have three towers? Four?

Sylvia.

Ha! Have to admit I've never heard *that* term before! (I'd call it a "hand truck") Mine is too big ("refrigerator dolly") to make that a practical solution: and the roadways are too "rough" of a surface (bumps, holes, curbs, etc.) to make it very "pleasant". (I used the refrigerator dolly to move a pinball machine a few blocks to a neighbor's house. It wasn't anywhere near as easy as I had *thought* it was going to be, despite the large wheels *and* a concrete sidewalk!)

I have the business half of an electric powerchair onto which I've fastened the "bucket" of a wheel barrow (gives me a motorized wheel barrow, in effect) -- useful for hauling the ~20 ton of "aggregate" into the back yard. When it's served its purpose in that form, I may play with reconfiguring it to move a person (though I think the gearing in the drive motors is wrong -- not a high enough speed to make it practical over long distances... except, perhaps, as a "power chair"! :> )

The same transport (pipelines, trains, trucks, etc.) that transport ethanol away from the site could equally easily transport water /to/ the site. Seawater is fine - you will be converting the water to steam anyway.

There would be plenty of investment costs in making such a plant, but once it is build, the running costs would be very low and the energy supply in a desert is plentiful.

(I don't know if there are suitable processes for producing ethanol from CO2, H2O and electricity/sunlight/heat, but certainly hydrogen can be generated from H20 and electricity. Ethanol would be more convenient, however.)

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people are playing around with photosynthesis, and one of the scheme produ ces hydrogen gas from water and sunlight - inefficiently, of course. It's y ears since I saw the abstract and I've got no idea where I saw it.

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e quite a lot of oil from coal during WW2, and it sounds as if somebody has revived the process to work with biomass rather than coal. The "70%" refer s to the process as a whole, which leaves room for a lot of fudging.

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s adds any new CO2 capture,

If there's a silly-greenie of the week competition, you'd have just won.

In reality I suspect that you are reading more into what was posted than wa s intended, but who cares - none of it is worth thinking about until we get a chance to invest in it.

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0%. The 70% claimed is remarkably good, and most likely based on a misconce ption.

I didn't actually see a plausible electrolysis component in the write up - I did see the word, but phrase might have meant that the writer though that the electrical heating to 800C and the consequent (minimal) thermolysis co nstituted electrolysis. I stick to my original position that the write-up i s essentially meaningless, probably intentionally so, and reading any signi ficance into the choice of words is a waste of time.

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Bill Sloman, Sydney

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people are playing around with photosynthesis, and one of the scheme produ ces hydrogen gas from water and sunlight - inefficiently, of course. It's y ears since I saw the abstract and I've got no idea where I saw it.

-temp

as

that, by

t.

e quite a lot of oil from coal during WW2, and it sounds as if somebody has revived the process to work with biomass rather than coal. The "70%" refer s to the process as a whole, which leaves room for a lot of fudging.

e process

the case.

s adds any new CO2 capture,

If there's a silly-greenie of the week competition, you'd have just won.

In reality I suspect that you are reading more into what was posted than wa s intended, but who cares - none of it is worth thinking about until we get a chance to invest in it.

naged to

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0%. The 70% claimed is remarkably good, and most likely based on a misconce ption.

I didn't actually see a plausible electrolysis component in the write up - I did see the word, but phrase might have meant that the writer though that the electrical heating to 800C and the consequent (minimal) thermolysis co nstituted electrolysis. I stick to my original position that the write-up i s essentially meaningless, probably intentionally so, and reading any signi ficance into the choice of words is a waste of time.

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Bill Sloman, Sydney

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ol of molten salts - big enough that it can stay hot overnight - and the st eam turbines that convert that heat into electric power can run all night.

tower set-ups far enough apart that only one of them is going to be shaded . And you can scale up the tank of molten salt so that it stays hot for a c ouple of days.

Two is better than one, and three is better than two. There are mathematici ans who can set up the problem as an exercise in optimisation. You are alwa ys going to need more installed capacity than you expect to be able to use.

Telephone systems get 99% accessibility by having four more connect paths t han the worst case requirement, which is a real imposition on a small syste m and lost in the statistical noise on a big one.

Another exercise for the tame mathematician. You want the towers far enough apart to be unlikely to be covered by the same weather system at the same time, but no further apart - because, as you say, power transmission system s cost money and have transmission losses (though 2000 km seems to be pract ical for high voltage direct current links).

We've already got a a power grid, for jobs like shifting power from the Sno wy River hydroelectric generators to the places that need it, so transporti ng power over long distances isn't exactly a serious problem.

How many big power stations have we got now?

lists five active roughly 2 GigaWatt coal fired generators, five gas-turbin e power stations, running from 50MW to 667MW, 24 hydroelectric power statio ns, most of them small, but one at 1500MW, another at 950MW and couple of a respectable size.

The biggest solar towers around at the moment are 350MW plants. NSW average electricity consumption is around 7GW so you might be asking the solar tow ers to supply maybe 2GW during the night - that's about six 350MW plants.

Again, you don't need a particularly high-powered optimisation exercise to get an answer.

It probably won't be the right answer, but close enough for this sort of di scussion.

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Bill Sloman, Sydney

US has 5 timezones, Australia 3. 2 more hours during a day in which the sun is "up", somewhere in the country (while another part of the country can benefit from the power it sources). Power can also be exported to Canada, Mexico/Latin America without a transoceanic cable.

Gee, on one hand, you claim US and Australia are "the same size"; yet, ignore the fact that population is 15 times greater. I.e., much higher (average) density in the US.

Top 10 US cities exceed total population of Australia. I.e. address their needs and you've met the needs of another "entire nation".

It also means that you have more opportunities to *consume* power before, as Sylvia stated (you *did* notice that I was replying to HER comment?) regarding "energy STORAGE"??

Because you have to convince monied interests that it is in *their* best interest to move from their current "investments" to *new* investments. Much easier to get individual homeowners/businesses to make their *own* choices and reap their own rewards -- with more efficient designs and sitings of buildings, etc.

E.g.,

Sure! We probably have 20% of this neighborhood using some form of solar power (PV's, solar hot water, solar pool heating). But, what my neighbor does isn't of any use to *me* -- and, some might consider ~2,000 sq ft of PV panels on a home to be an eyesore. A large parabolic reflector undoubtedly would!

If it was that easy, then *our* hot water heater wouldn't kick in after a shower! How big do you want that tank to be? A 10 minute shower with a "low flow" (2.5GPM) showerhead will consume more than half of the water in a nominal 40G hot water heater. Group showers??

I'm not saying it *isn't* possible, currently. Rather, that "live feeds" for an entire workday (the equivalent of being able to see your fellow officemates "face to face" -- multiple streams) would be a piece of cake with high speed service to *every* home. (you also need that link for data *while* watching the streams -- e.g., applications served over VPN)

How often do you need to "look" at the olive oil you purchase? ("Joe, send us 3l of Colavita, EV, cold-pressed") Toilet paper? Other "sundries" (dry goods, canned goods, etc.)?

We typically visit 5 stores in a typical (weekly) "shopping day". The only items that I couldn't trust an impartial grocer to pick

*for* me are meat and produce. Yeah, he may opt to deliver the gallon of milk with the shorter expiration date (while there may be another next to it on the shelf with a LONGER date). But, it's in his best interest not to make a habit of screwing over his customers -- as those customers could just as easily "phone" (internet) their business to another vendor across the street from him!

So, if "home delivery" was a practical option, we'd visit just

*one* of those stores; two, some weeks. [I believe some stores are now opting for this sort of service, esp in cities where "shopping" without a car can be much more difficult!]

I'm not talking about "pump generators". Rather, ways to store energy.

*You* want to use it for electric loads. Why can't it also be used for heating/cooling? By far the *largest* loads!

Neighbor across the street has an "all electric" house. And, a decent size pool in his yard. Why use air-sourced heat pump to heat/cool when the "pool-sourced" would have a much better CoP? And take *less* volume for the mechanism!

At ~5KW (if you want to *begin* to address cooling loads), I think you're looking at ~$20K+ for a PV installation. Remove the grid as a storage medium and you are probably at closer to 6 or 7KW to handle a peak cooling load (assuming you can shed other loads as required).

[Of course, there are incentives to make that figure more palatable. But, no reason to think similar incentives wouldn't apply to other technologies -- bottom line is producing energy]

Hard to imagine a Stirling/dish solution costing *more* than that (if produced in the same volumes).

I suspect much of the initial appeal of PV's will turn to sour grapes once they've been deployed for a while -- repairs, general building maintenance, etc. I will be interested to see how some of our neighbors deal with routine roof repairs with all that cruft up there! (pay for removal and reinstallation every decade??)

We have (advertised) "360 days of sunshine per year". I thought it was a bit overly optimistic when I first heard it -- but now realize it is probably true. You *notice* the few days when it *isn't* sunny!

urning fossil carbon, but that's because the generating stations don't have to pay the price they ought to for the privilege of dumping CO2 into the a tmosphere.

s. We have made a lot of progress in the last 200 years. We have enough known fossil fuels to last another 200 years. I have faith that we will ma ke more progress in the next 200 years. But until solar power is cheaper t han fossil fuels , nothing significant is going to happen.

In quite a lot of applications it is already cheaper. About half the price most people pay for electricity is the cost of transporting it to their hom es.

If we got most of our power from solar cells, the economies of scale would mean that it was the cheapest source. Germany halved the price a few years ago by ramping up manufacturing capacity by a factor of ten, and China did the same thing again more recently, and there's room to halve the price yet again by the same trick.

And if anthropogenic global warming gets more obvious than it already is - and it's already obvious enough to worry anybody less complacent than John Larkin - there will be an even more significant pressure to stop boosting t he CO2 level in the atmosphere by burning fossil carbon as fuel.

When the Greenland and West Antarctic ice sheets start sliding off into the ocean, and all our coastal cities start having to cope with 10 metres of s ea level rise, even John Larkin will have to take notice, but nobody has mu ch of a clue when that's going to happen.

It will be sooner than it would take to melt the ice in place.

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At the end of the last ice age the Canadian ice sheet slid off into the sea while it was fairly thick, and dumped enough ice in the North Atlantic to kill off the Gulf Stream for 1300+/-70 years, which does suggest sooner rat her than later.

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Bill Sloman, Sydney

The fuel cell was invented 177 years ago, and remains the technology of the future.

A few years back, lots of people were promoting fuel cells to power laptop computers. It was the rage.

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John Larkin         Highland Technology, Inc 
picosecond timing   laser drivers and controllers 

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com