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138 comments on Wednesday Open Thread

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Physics Grad on May 3, 2006 - 7:01pm Permalink | Subthread | Parent | Comments top
The problem with wind (solar) energy is that it only works when the wind is blowing (sun is shining).  We can't really go without good sources of generation where we hit a button and get x amount of energy out.

What we really need to start talking about and researching is a good way to use less energy on a large scale.  There just can't be a good solution if we keep burning through energy at the rate we are.
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pondlife on May 3, 2006 - 7:24pm Permalink | Subthread | Parent | Comments top
Sure, use less electricity. Ban filament bulbs.. Set up a semiconductor fab plant in the UK making LEDs and solar arrays for the UK.

incidentally we have base load power renewables
The Severn barrage proposed in 1938 [I'll check the date when I'm back home] had 2 tidal pools for continuous power
and pumped energy storage. People have been finding excuses to refuse this, and other tidal stations for 60 years minimum.

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MillMan on May 3, 2006 - 7:24pm Permalink | Subthread | Parent | Comments top
Right. Wind and solar aren't the magic elixir that fossil fuels are, so let's just forget about them! Perhaps we could do something radical and, say, funnel $ 50 billion into energy storage research? That's peanuts for our prez. And why aren't Western European governments going down that road either?

The energy crisis is going to require many different technical efforts and social changes (including large reductions in energy use like you said) because there is no magic replacement for fossil fuels. To reject wind and solar on the basis that they aren't an on-demand energy source is a poor argument.

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Physics Grad on May 3, 2006 - 10:28pm Permalink | Subthread | Parent | Comments top
I'm not rejecting wind and solar -- they're great.  But they just can't be the baseline energy source because they are intermittant.
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Elizaphanian on May 3, 2006 - 10:32pm Permalink | Subthread | Parent | Comments top
There was a study released a month or two ago, referring to the UK, showing that the wind is always blowing >somewhere< in the UK. It means that there needs to be significant spare capacity (and storage) but wind is clearly the #2 answer (after conservation).
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Biochemist on May 4, 2006 - 12:54am Permalink | Subthread | Parent | Comments top
I totally agree with Elizaphanian.  This country could build a new and highly redundant long-distance electrical system to handle the electricity generated from thousands of wind farms all across this country.  It might take 10 years to build this network but it could be done.  And there is always wind blowing somewhere in this country or on the coast.  Utilzing this new grid on top of the existing power grid, I think we could provide a fairly constant and substantial power supply for this country.  This would then lead to a substantial reduction in our dependence on fossil fuels.
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SHiFTY on May 4, 2006 - 8:52am Permalink | Subthread | Parent | Comments top
It could be done- at vast, huge, uncomprehensible cost to the public and industry, and only after vandalising most of the remaining countryside with windfarms.

I remember reading that you need 8 MW of wind to replace 1 MW of coal/nuclear baseload because of the intermittency. At this ratio, to replace a single 1GW nuclear station you would need 3 or 4 thousand monster turbines at a cost of many tens of billions of pounds, not to mention vast quantities of steel and concrete, an army of installers and maintainers, and a legal team to shut down objections from angry country dwellers.

So much for sustainable, and thats just replacing a single power station!

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AlanfromBigEasy on May 4, 2006 - 11:32am Permalink | Subthread | Parent | Comments top
The ratio is closer to 3.5 to 4 MW wind to 1 MW if pumped storage is used.

"Vandalize the countryside".  Yes, some people's aesthetics will be sacrificed, others will come to like them (particularly with time).  Some Icelanders oppose planting trees, even though Iceland was covered with trees "from the sea to the mountains" before their ancestors cut them all down for sheep.  They prefer their environmental stripmine.  OTOH, the Dutch like and try to preserve their old windmills.

All in what you are used to !

A wind turbine can replace the energy used in it's manufacture in about a year or so, with 20+ more years to add to the economic surplus.

And I STRONGLY suspect that lawyers are a renewable and sustainable resource :-P

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Siggi on May 4, 2006 - 11:48am Permalink | Subthread | Parent | Comments top
In Germany, we had all these discussions, too. In the beginning, wind power was sometimes built too close to houses, some made too much noise and some had the dreaded "disco effect". These problems are pretty much fixed now.

Newer wind energy converters now have up to 6 MW.

It makes a lot of sense to build wind parks offshore. First of all the wind is stronger there, it blows more steadily, and the wind energy convertes obviously don't vandalize the landscpae out there.

A lot of wind power has also been built next to highways and motorways recently.

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Physics Grad on May 4, 2006 - 11:59am Permalink | Subthread | Parent | Comments top
Yeah, I used to see a bunch driving south from Mainz along the highway.  I thought they were actually pretty cool looking and not as ugly as many people say.
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AlanfromBigEasy on May 4, 2006 - 1:48pm Permalink | Subthread | Parent | Comments top
> obviously don't vandalize the landscape out there.

The "limousine liberals" of Cape Cod island Massachusetts strongly support renewable neergy, except when a proposed offshore wind farm might clutter their view of the ocean.

Computer simulations show very small images out at the horizon.

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Siggi on May 4, 2006 - 2:05pm Permalink | Subthread | Parent | Comments top
That's why in the North Sea, the wind parks are planned out of sight from the coast...

Obviously, the sea has to be quite flat for this to work.

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solar1 on May 4, 2006 - 3:51pm Permalink | Subthread | Parent | Comments top
We have already destroyed everyone's view with electric poles from coast to coast.  After that we added cell phone towers everywhere.  I don't see how we can complain about a few windmills.  Soon renewable energy will be all we have, like it or not.  It takes a lot of work and only provides a spit of energy for your trouble and it is all we will have.  
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Siggi on May 4, 2006 - 4:28pm Permalink | Subthread | Parent | Comments top
Actually, there is a problem now with the power lines. In order to connect all the wind power in the north, where not that many people live, to the urban centers, we need more power lines.

As always, there is NIMB attitude. Each small village demands underground cabling, but for a 380 kV line, that is exorbitantly expensive. As a result, it takes 10 years to build a new power line - the wind power is growing much faster.

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Joseph Palmer on May 4, 2006 - 11:40am Permalink | Subthread | Parent | Comments top

The back of the envelope cost for Megawatt class Windmills is about $1 USD per Watt. (.54 GBP)

To replace a 1GW power station with Wind would cost roughly $8 Bn USD

Now I don't know if you've priced a new Nuclear Power plant lately, but a while back I Googled about to find out how much they cost. link

Nuclear power's biggest problems are economic: it is simply no longer competitive with other, newer forms of power generation. The final 20 U.S. reactors cost $3 to $4 billion to build, or some $3,000 to $4,000 per kilowatt of capacity. By contrast, new gas-fired combined cycle plants using the latest jet engine technology cost $400-$600 per kilowatt, and wind turbines are being installed at less than $1,000 per kilowatt.

In other words, Wind costs 1/4 to 1/3 per watt of installed nameplate capacity.

Let's assume you are correct, and that the real ratio is 8:1 to handle the baseline load. That mans that you need to spend twice as much on windmills as you do on a Nuke Plant.

Of course, it takes 7 to 10 years to complete a Nuke plant, and there is NO electricity for those years, and the interest on the loans to build the thing just keeps rising. Then once you have completed it, you need to fuel it, and we have only found about 50 years of good EROEI uranium, (At present use rates) and as the purity of the remaining ore goes down, the amount of fossil fuels to mine and refine it goes up. THEN, at the plant end of life, you have to decommission it and store the waste for several times longer than recorded human civilization.

With a wind farm, you can begin electricity production as you add towers, and they economically pay for themselves in less than a year. There is no ongoing fuel cost, minimal downtime for maintenance, and when they wear out you can re-use the tower (Which is a significant portion of the cost) with a new generator and blades. If you want to decommission one, you show up with a crane and take it away to melt it down to make a new ones.

The notion of thousands of windmills somehow seems to creep people out, but compared to the scars on the planet caused by our use of fossil fuels I'd choose them in a heartbeat. Besides, maybe if we saw them every day we'd be more aware of our energy use.

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Siggi on May 4, 2006 - 12:24pm Permalink | Subthread | Parent | Comments top
Maybe this is not widely known, but in Continental Europe, we already have an integrated power grid, UCTE.

The "Union for the Co-ordination of Transmission of Electricity" (UCTE) is the association of transmission system operators in continental Europe, providing a reliable market base by efficient and secure electric "power highways".

50 years of joint activities laid the basis for a leading position in the world which the UCTE holds in terms of the quality of synchronous operation of interconnected power systems.

Through the networks of the UCTE, about 450 million people are supplied with electric energy; annual electricity consumption totals approx. 2300 TWh.

Only the UK, Scandinavia and the Baltic countries are not part of the grid, but there are links as well from Denmark, Germany and Poland to Sweden.

The international links are not very strong now, but the EU is working on expanding them.

In the future, offshore wind parks in the North Sea, the Atlantic, the Baltic Sea, and Solar in Spain, Italy, southern  France could provide a very reliable energy source for Europe.

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pondlife on May 5, 2006 - 5:43am Permalink | Subthread | Parent | Comments top
The UK can transfer electricity with France via a N Sea cable. Since our systems are not synchronised, they have massive convertors [a bit like the SMPS that runs your PC]
to convert 'Frog mains' to UK mains
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B612 on May 4, 2006 - 9:09pm Permalink | Subthread | Parent | Comments top
Here's an older one but plenty more news on that site.

New report confirms UK has best wind in Europe

from the news item
"the chance of low wind speeds affecting 90% of the country only occur for one hour every five years, whilst the chance of wind turbines shutting down due to very high wind speeds only occurs in around one hour every 10 years. Other findings concluded that the wind conditions in the UK are significantly stronger than those in Denmark and Germany, making wind power a very real option and opportunity for the UK, as the country has 'the right kind of wind'."

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jbecker on May 3, 2006 - 11:02pm Permalink | Subthread | Parent | Comments top
Power storage is a component of some planned solar power stations in Spain. See figure 2.5 on page 19 of this document: Concentrated Solar Thermal Power Now

Power storage in solar thermal generating systems is relatively simple: two tanks, a heat exchanger, and a pump.

"The proposed 15MWe Solar Tres plant in Spain will utilise a 16-hour molten-salt storage system to run on a 24-hour basis in the summertime."

Tanks size is limited only by economic factors. The tanks could be sized for more hours of storage.

More on molten salt here: Advantages of Using Molten Salt

In addition, solar thermal systems of this type can be used as a fuel-saving "booster" to existing steam-driven power stations by preheating the water before it enters the boiler: Stanwell Solar Thermal Power Project. Seems like this approach could be part of a transition strategy.

Similar systems could be used to supply or supplement process heat for manufacturing, reducing demand on fossil fuels.

Jeff Becker

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Wolfric on May 3, 2006 - 11:41pm Permalink | Subthread | Parent | Comments top
Hi Toders

Regarding the limits toward renewable energy, Ted Trainer has put up lots of research to analyse the current offer.

Note that personnaly I think that small scale wind turbines may be some kind of solution.  Small scale wind turbines can be fixed using garage technology and can even be made by using scrapp copper, aluminium and steel.

I say scrap metal because I dont think we will be able to bring much solution before system collapse hapen because of the enormous inertia in the whole society.  Scrap metal will be found in cars, houses, etc.  

You have to think that when you will be implementing solution, the following wont be available : current systemic stability and working economy.  

Wind and hydro turbines will be used for small scale application.  See the hydro ones for grounding wheat or powering water pumps for daily consumption.  Also some lightning may be available in some spot place but I doubt you will be able to find a led, fluorescent or event incandescent light bulb.

In fact I dont think no one really knows what is gona be available in the next decade or so.  Heck, we almost cannot think clearly of what is gona be usefull.  

Making a garden is a must but how do you preserve the food? I doa lot of home canning and one thing I can tell is that the snap lid has to be replaced each time you do a new can.  That thingny has a rubber band on it.  How are we gona be replacing those snap lid? What can be used in place of that?  What were we using before glass and metal can?  

Those are good questions.  

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john milton on May 4, 2006 - 12:12am Permalink | Subthread | Parent | Comments top
Resist the urge to panic, it's not going to do you or the ones you are with any good. You cannot plan or mange this unwinding yourself, you need to get your head around going with the flow.

Gaskets will be important for the forseeable future, the need to seal pipe joints, steam engine valve chests, water pumps, and canning jars will no doubt persist :-). They can be made from Latex rubber which is renewable, imported from the east on the sailing ships which may one day fill the seeways again. They can also be made here from bio-source plastic (maybe we will start with milkweed sap, or canola oil and start building up the hydrocarbon chains I have no idea, but it can be sorted out), bio-resin impregnated natural fibre, or even oil / NG based plastic, who cares if the eroei is <1 we are making a reuasable artifact of great value from it, not burning it.  

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jokuhl on May 4, 2006 - 3:35pm Permalink | Subthread | Parent | Comments top
Fun Polymer-making in your kitchen..

"Green Plastics: An Intro. to the new science of Biodegradable Plastics"  E.S. Stevens - Princeton U. Press, 2002

About half is on the chemistry of conventional polymers, thermosets and thermoplastics, and then segues into non-petrol based formulas and experiments (celophane, etc)..  Great info.. gotta read it a couple more times to really get it..

Bob

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Autodidact on May 4, 2006 - 10:26am Permalink | Subthread | Parent | Comments top
Before they made those snap lids, canning jars had removable rubber gaskets and the jars had metal closures--I don't know how to describe them except that you can still find them on some cannister type jars.  Before canning technology was available, people dried food for long term storage.  All you need is sun, a breeze, and something to keep the bugs off; also food (meat) was stored in brine, and apples, potatoes, etc. were stored for several months in root cellars.  There are lots of alternatives to canning as we know it.  Drying racks are easy to make out of scrap wood and old screens.  The Foxfire books have lots of good info on pre-oil age living.  There's also tons of other books about these subjects out there--everything from survival manuals to ethnological studies of tribal people.      
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Leanan on May 4, 2006 - 10:55am Permalink | Subthread | Parent | Comments top
A picture is worth a thousand words. ;-)

Of course, now they tell you not to use those, because they aren't safe.

I wonder how practical canning will be in the long run.  It takes a lot of energy, since everything has to be cooked and sterilized.  Not to mention the cans, glass jars, seals, gaskets, and what have you.

Canning is a pretty recent invention; canned food was too expensive for ordinary folk to afford until mechanization made it cheaper and faster.

The pickling practiced by Asian cultures might be more practical, as long as salt is available.  

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geoff on May 4, 2006 - 11:38am Permalink | Subthread | Parent | Comments top
"Carla Emery's Encyclopedia of Country Living" is a book worth having in addition to the Foxfire series. From plants and gardening to food preservation and animal husbandry, bee keeping alot of info collected over the years put in an easy to find and read layout. A freind of mine showed me a original copy he got back in the 70's, hand typed and with cereal box covers and twist tie for bindings. I bought a dozen copies to keep on hand for family and freinds if and when the time comes. A well stocked pantry is money in the bank for me and knowledge in hand is treasure.
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Todd on May 4, 2006 - 10:18pm Permalink | Subthread | Parent | Comments top
I would also suggest "Country Wisdom & Know-How" from Storey Books, ISBN 1-57912-368-6, as a complement.  It is a Whole Earth Catalog-sized publication.  In fact, even though TWEC is obviously out of date, it (they) still have valuable information.  My oldest one is from 1969 and my newest is from 1974.

For those who don't know, Carla died last year in her early 50's.  She will be missed by many.  She was truly one of the good people in the world.

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geoff on May 5, 2006 - 8:12am Permalink | Subthread | Parent | Comments top
Todd
   Thanks and I will look for that book. Carla has a web site http://www.carlaemery.com/ with alot of stuff there. Her husband Don is carrying on with what she started and sent a hand written note thanking me for the order I placed. Don't see that much these days. And I think her 5 key lifestyle principles of Homesteading apply in the city or country.
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AlanfromBigEasy on May 3, 2006 - 11:15pm Permalink | Subthread | Parent | Comments top
Wind and hydro (storage more than run-of-river) are an ideal match from an electrical quality POV as well as storage.  Slow hydro to almost nothing when winds are high late at night; run hydro all out when winds are low at 6 PM peak.

An alternative is pumped storage with similar qualities, but not at a net energy gain.  And the amount (total energy) stored in projects to date is fairly low, but this could be changed.  High output for some hours is common.

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Slarkki on May 4, 2006 - 6:25am Permalink | Subthread | Parent | Comments top
Greetings. I've been following the discussions on this site for quite some time now and finally decided to register as a user. This is my first post but now that I have registered I might open my mouth on a regular basis.. unless I manage to make a total fool out of myself. grin

I personally think that Wind,Solar and Hydro power are the best we'll ever have before we can figure out how to make fusion power happen. Although I fully support nuclear power I can only see it as a temporary solution unless we can make fission happen with something a lot more commonly available than Uranium. I think our Solar tech is a bit lacking but in some areas it can still beat the Wind.

Hydro power is indeed good for baseline energy production but Wind power is too erratic in nature. Wind power could be made to work properly if there was a way to store the power somehow. Flow batteries don't quite cut it imo and hydrogen technology isn't quite there yet as far as I know, but how about hydro power? I mean technically we could pump water up to some kind of large reservoirs and run the water down through hydro plants when we need the power. The question is that how horribly inefficient would that be? Pumping operations of that scale would probably cause some kind of erosion and if the water is salt water there could be a number of environmental problems perhaps but.. you have to start the line of thinking from somewhere.

If we could secure ourselves enough reliable electricity profuction we could always produce the various substances we absolutely need for various purposes. I am quite aware that the days of cheering for consumption are numbered and I think that this is a good thing, but I still think civilization does not have to fall but I sure won't be missing the modern form of capitalism.

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Twilight on May 4, 2006 - 6:46am Permalink | Subthread | Parent | Comments top
Welcome!  Actually pumped storage is common on the electrical grid now.  It's used for leveling the demand, and probably helping with system stability.

Maintaining system stability is tricky stuff, and requires a certain amount of excess capacity.  Of course, that's if the grid IS interconnected!

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AlanfromBigEasy on May 4, 2006 - 8:02am Permalink | Subthread | Parent | Comments top
http://www.tva.gov/sites/raccoonmt.htm

One of several pumped storage projects in operation today.

Effiency varies a bit depending upon equipment, but 15 MWh out for 19 MWh in would be a good #.

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Slarkki on May 4, 2006 - 9:26am Permalink | Subthread | Parent | Comments top
Ah, so it would and indeed does work in practice. If the efficiency rating is that good there's even room left to maneuver. Economical in no means by today's standards and the project would be colossal like in the scale of nothing that has ever done before and would probably take decades or centuries but.. theoretically we could create artificial rivers and even use them to fight drought?

Sounds very much like SciFi and there are big issues ofcourse like where to get that water. I'm assuming here that running rivers of salt water would at the very least be bad for ground water. At least a project of this magnitude would give people some purpose.

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uterenonnumera on May 4, 2006 - 1:44pm Permalink | Subthread | Parent | Comments top
Alan,

Very interesting. How far could pumped storage be scaled down and make sense? Surely not to the household/neighborhood level? You engineering types might chime in... how many kwh are there in, say, 500 gallons of water....

specifically, if one used solar, wind, whatever, to fill a 500 gallon drum with water, then released the contents over a wheel, driving a generator, how much electricity could one produce?

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AlanfromBigEasy on May 4, 2006 - 1:58pm Permalink | Subthread | Parent | Comments top
MHyLab in Switzerland has designed a 100 watt (0.1 kW) hydroelectric generator for a French (?) company to sell for cabins, etc.  Smallest that I know of.

The unanswered questions are how high the drop with 500 gallons and how long do you want power ?

Two farm ponds with, say, 50' (15 m) difference in elevation could store a fair amount of energy.

For a home, an attic (2 stories up) or concrete holding pond up a hillside with a below ground cistern might work well.

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uterenonnumera on May 5, 2006 - 9:35am Permalink | Subthread | Parent | Comments top
Thanks for the response. The higher the water, the more potential energy, but what would be practical for a home-owner who doesn't own a hill? Tanks in the attic as you mentioned. But then, what about freezing conditions? And structural reinforcement would be required for all the weight. I like the cistern idea...

Does make me think, though, of all the kinetic energy that is represented in storm water runoff.

Micro-hydro...

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Twilight on May 4, 2006 - 8:52pm Permalink | Subthread | Parent | Comments top
That's a good point, and I'm going to have to calculate that out.  Might be a viable project for home fabrication.  Perhaps a solar heat engine to pump the water up.  Somehow I'm more interested in non PV solar.
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AlanfromBigEasy on May 4, 2006 - 10:47pm Permalink | Subthread | Parent | Comments top
I have noted a Finnish small wind turbine that seems ideal for many sites (including inside cities).  Feeds low voltage DC (choice of 12 V, 24 V & 48 V I think).  Include a battery to stabilize system and low wattage/low voltage water pump and "voila".
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Engineer-Poet on May 3, 2006 - 7:33pm Permalink | Subthread | Parent | Comments top
You can do a heck of a lot with intermittent sources if you have storage handy, and the storage is also good for price arbitrage between peak and wee-hours power.  It is too expensive to store electricity for most uses, but if you need A/C you can store ice, and you can heat a tank of hot water before you need it or hotter than you want it and use the heat (dilute the hot water with cold) later.
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Twilight on May 3, 2006 - 8:31pm Permalink | Subthread | Parent | Comments top
The hot water tempering (extender) valve has been around for decades, used especially on oil fired systems.  It's just a thermoststic blending valve, so that the system can cycle up and down at a temperature above the desired output temp.  You can get them at Home Depot in season.  This plumbing stuff was worked out a long time ago.  I've really got to find time to make a solar hot water pre-heater!

Why don't we focus on vacuum thermos hot water tanks and such?

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Substrate on May 5, 2006 - 1:48am Permalink | Subthread | Parent | Comments top
I share your interest in non-PV solar(though I'm assuming you mean direct use solar-thermal).  The beauty is that it's relatively simple, and you're just moving heat around and not transfering forms of energy.  Also, storage is simply water...at 4.18 joules/gram degree C, water has one of the highest specific heats of any substance.  After conservation it's probably the next lowest hanging fruit to be plucked and it directly impacts the two of the greatest uses of energy in a home - Heating Water and Space Heating.  Space heating IIRC(but I only recall very hazily, so someone curious enough might want to hunt the figures down), either rivals or exceeds individuals consumption of transportation fuels.

I visited the house of a retired fellow in WNC who had built an active/passive solar house (off grid).  It was huge, I'd guess around 5000 sq. ft. open layout, small-ish greenhouse for passive solar, and partially built into a hill with good insulation.  3kW PV system with battery backup.  He used 4 - 4X6 ft. flat panel colletors in the thermal system and had a 5000 gal tank (a discarded stainless steel milk vessel) in a super-well insulated room of it's own.  He had a backup system (it was just a regular water heater) but said he never had to use it.  It provided the heat for the house and the shower.  He told me the tank would get up to 150 degree F.  At the time he told me the equivalent energy that it held at that temperature but I've since forgotten, so I did some (literally back of an envelope) calculations.

5000 gallon tank
Assume 150*F to 80*F useable range (delta 70*F or ~39*C)

5000gal*(3.785Liter/1gal)(1000g/1L) 39degC * (4.185Joule/gram * degC) = 3089581950 Joules

3089581950 Joule (.00094978 BTU/Joule) = 2934423 BTU

Or... ~23.66 gallons of gasoline (based on BTU's) of storage if the tank is at 150 degrees F.

A crash program aimed at solar thermal heating would take a huge burden off of fossil supplies(since a lot of homes use natural gas, propane, or heating oil, some water heaters are propane or nat gas) and also the electrical grid (water heating, and some homes).  I just tracked down some quick and dirty numbers... 43% of home energy cost is for Space Heating, and 16% for Water Heating.  So that would represent a huge reduction in a home's fossil fuel usage.

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Twilight on May 5, 2006 - 9:21pm Permalink | Subthread | Parent | Comments top
I'm going to have to retrofit systems into our old house, but I still see passive solar heat and hot water pre-heat as some of the best things I can set up.  

The amoount of heat that collects in even the poorly insulated (insulated hell, it has holes in it!)sun-porch I'll be rebuilding this summer is quite impressive.  If I can seal it and insulate it half decently, it will be an impressive heater this winter.

I've been looking into water storage tanks - there are some large plastic water tanks for agricultural use that might work well.

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wimbi on May 5, 2006 - 4:46am Permalink | Subthread | Parent | Comments top
A simple number to remember is 1 liter of water lifted 1 meter in one second is ten watts of power, and ditto down.  So for example, 1 cubic meter of water is 1000 liters so 1 cubic meter of water lifted 1 meter in one second takes 10kW.  Or gives 10kW if dropped.

OK, you nitpickers, it's really 9.8 watts instead of 10, but we engineers don't need to mess with anything but pretty good estimates, right?

And, of course, you have to think about the pump/turbine/alternator efficiency, which at absolute best is maybe 90% and a lot less if very small (1kW)

I have a small pond 20 meters down from my house.  And I have a great southern exposure nearby, so I am playing with the idea of a pumped storage system using a free cylinder stirling water pump that some people here are thinking of putting into production.  As always, the concentrator is the $ problem.  So that puts me right back at the biomass burner, which does look feasible.   Around and around.  Better start making some real decisions.

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haggisbasher on May 4, 2006 - 2:49am Permalink | Subthread | Parent | Comments top
Tidal energy has the potential to be the most reliable source of electricity for the UK, it is predictable years in advance,  and minimally impacted by weather.  For any one station outputs will vary throughout the day, but as maximum flow rates occur at different times around the coast, overall there will always be a certain level of generation.  With the predictability, industrial usage can be timed to take advantage. (Something which I believe will be more and more common - the power is used when it is available).
What percentage of requirements can be met, and how quickly the infrastructure can be put in place are the big questions.
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haggisbasher on May 4, 2006 - 3:13am Permalink | Subthread | Parent | Comments top
 Oops - forgot the link. (too early - not enough caffeine) http://www.hie.co.uk/aie/tidal_power.html
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AlanfromBigEasy on May 4, 2006 - 5:24am Permalink | Subthread | Parent | Comments top
I was struck by how small the projects were.  One had potential for a maximum of 2 GW, but that was in spring apparently.  The rest were much smaller.

Remember, tidal power is availabel for a few hours out of every 25 hours  (The power peak rotates around the clock over the lunar month).  So any peak # has to be multiplied by it's load factor, which is typically ~21% for US wind turbines and probably worse for tidal power.

A single nuclear plant could produce more than all the projects listed.

Where tidal power makes sense, go for it.  But it is not even close to being a complete solution.  Wind plus hydro (old + new) seem to be the best paths.

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ericy on May 4, 2006 - 9:10am Permalink | Subthread | Parent | Comments top

Yeah, but as you move up and down the coast, the time of high tide changes.  If you install the things over a large enough area, it can average out, at least to a degree.
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haggisbasher on May 4, 2006 - 9:25am Permalink | Subthread | Parent | Comments top
Completely agree that tidal (or any other system) will never be the complete answer. The best estimate I have found for UK is 20% of requirements, and we are probably one of the best locations for this.  The advantage lies in the complete predictability of the supply, something which is difficult for wind turbines to provide.  
   The 240MW tidal barrage at La Rance in France has been operating since 1966,and is producing 640 million kwh / year.  That gives a load factor of around 30%.
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AlanfromBigEasy on May 4, 2006 - 11:23am Permalink | Subthread | Parent | Comments top
AFAIK, La Rance is also used for pumped storage when the monthly timing is right.  It is quite good in that one can pump water up, say, 80 cm and release that same water with a 1.5 m head, gaining and not losing energy.

A good use of the project, but it also distorts the load factor #s.

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tom deplume on May 4, 2006 - 4:36pm Permalink | Subthread | Parent | Comments top
Ocean currents of more than 4 kts within 100 miles of shore could be a reliable source of baseline power. The Gulf Stream from Miami to North Carolina could meet all the energy needs of the entire United States.
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