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(Solar) Power to the Masses
D3 writes "This report on a solar power tower (pdf) looks extremely interesting. Maybe one day we can have international power lines where all the countries with lots of sunshine provide power to the rest of the world? How cool would that be?" The NY Times has a good article on solar power in Japan.
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Discover Magazine just did a story on something like this. Unfortunately the full story is only available in dead tree format. If you wait until next month the older article will be available. You can probably check it out at your Dentist's office like I did if you feel like getting a filling.
EnergyInovations is working on a small version. From the Discover article it discusses how they refined the stirling engine with the best tradeoffs of manufacturing costs to effiency. IIRC they are also making this small enough to make it fit on a roof top.
Geek fact of the day: A stirling engine is an external combustion engine that runs off the pressure created when one side of its engine gets very hot while the other side stays cool. The greater the temperature difference, the greater the pressure, the greater the energy generated.
I hope that someday we will be able to put away our fears and prejudices and just laugh at people. - Jack Handey
I don't know the percentages, but if you were to transfer power from say Mexico to Canada under this scenario, your energy losses would be huge.
global warming: increase in heat-retaining gasses reduce dissipation of energy from the plaent/atmosphere. since the input of energy from the sun remains constant, mean temperatures rise.
ozone depletion: stratospheric ozone (o3) blocks high-frequency solar radiation on its way to the earth's surface. less o3 means more high-frequency radiation.
since solar panels (photovoltaics) are more effective with high-frequency radiation, ozone depletion increases their output.
global warming just sucks
2 1337 4 u!
http://www.eere.energy.gov/csp/csp_tech.html Sandia actually did quite a bit of research on solar power towers. When Bush got into power, alot of the funding was taken away. Israel's Weizmann institute actually has a working power tower that is more advanced than the ones made at Sandia. http://wis-wander.weizmann.ac.il/site/EN/weizman.a sp?pi=420&doc_id=731
Answer:
Sure but it would suck.
The reason its so cold there is because what sunlight hits does so at an extreme angle.
Its hot at the equator because the sun is beaming straight down.
A square foot of ground in Mexico gets an order of magnitude more light energy hitting it than a square foot in antarctica.
Besides, it's pitch black 6 months of the year at either pole.
I don't need no instructions to know how to rock!!!!
After reading the article, this plan to use sun-tracking mirrors to melt salt sounds a little more complicated than this Australian plan. Not only that, but the Australian plan scores more points in the coolness department as the project intends to build the world's tallest structure -- a tower 1 kilometer high. BTW, IANAA (I am not an australian)
Yeah but in those case your talking about quebec selling power to the north east which is right next door. So you don't have to go very far.
Possibly the best do it yourselfer magazine I have ever read is dedicated to renewable energy and guerrilla solar.
Home Power Magazine
Wax on, wax off baby!
The problem is not and never has been generating the power, the problem is storing the power. The power companies barely buy power from individuals; It costs several thousand dollars for the required hardware, and even then they pay you much less than you pay them for power.
So, how do I cheaply, safely, and non-annoyingly store electrical energy (in some form) and how do I get it back to being usable electrical power later? It's trivial to build wind generators using automotive generators, and build solar panels out of broken solar cells, and for that matter to build your own gas generators using alternators. They kick out 12V which is useful on its own, and you can always use inverters to spit out 110VAC or what have you.
If you get slightly more uppity you can build your own three phase alternators and use them to drive three phase motors, which are commonly used in machine shop equipment.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
I don't know much about microwaves, but this story at ABC News seems like a pretty amazing idea (Summary: cover swaths of the moon with solar panels and beam the energy back to Earth via microwaves). What's 150 billion in the grand scheme of things?
There'll still be the idealists who scream about defacing the surface of the moon, but it would be relatively low maitenance (no elements to damage the panels, except for the occasional meteorite) and wouldn't take up precious space here on Earth, where things can grow or live. As romantic as some of us can be, the moon is still just a big chunk of lifeless mafic rock.
Anybody actually have an idea how well this would work?
Small is Profitable by Amory Lovins of the Rocky Mountain Institute is about the benefits of generating your electricity using small, modular power systems where you need them. It turns out that grid infrastructure is often well over 50% of the cost of providing power, and that if you simply install systems like microturbines or small-scale combined wind/solar installations (explained below), you can significantly outperform the grid in terms of end-user price and capital requirement.
That's not a big deal here, where we already have a grid, but it's a huge, huge deal in the third world.
The combined solar/wind thing works like this. Electricity demands have a thing called a "load shape" - basically demand graphed against time. It turns out that solar energy supplies match the load shape of things like air conditioners pretty well, but when the clouds come out, your solar supply goes to hell.
However, wind systems work best when there's a sudden change in temperature, causing new low or high pressure areas, so usually cloudy days have ample wind. If you combine local solar and wind systems in a single "local area grid" you get a hybrid system which produces power in almost exactly the same loadshape as your actual demand, reducing expensive overcapacity, and with excellent availability in all weather conditions.
Renewable energy requires a lot more smarts than "this is a huge factory which produces megawatts a day" - you don't see nearly the full benefit unless you actually take advantages of the full range of renewable solutions, using factors like their modularity, size, loadshape matching, low capital requirements, grid independence and many other subtle factors.
Small is Profitable is a hard read: about 400 pages of really densely argued financial and technical analysis, but it's pretty much the definitive work in the area. If you want to know more, it's the book to get.
Hexayurt - open source refugee shelter,
www.homepower.com is a great site That always offer their current magazine as a free PDF download. Most issues will show several complete setups including diagrams, results, and pictures of several different types of setups. Just in the past I've seen solar, hydroelectric, thermal water heating, and recipies for making bio-diesal from waste cooking oil.
Chika Chik-ah... do-e ow ow.
Intro blah blah blah...corporations and patents...blah
9. PRODUCT'S PRIMARY FUNCTION The primary function of a solar power tower is to produce clean electricity for the world's electricity grids. Solar power towers:
Dispatch electricity to the grid when needed--even at night or around-the-clock,
Are unique among solar electric technologies in their ability to efficiently store solar energy,
Are non-polluting and do not release greenhouse gases, and
Will be the lowest-cost solar electricity. The concept is simple: A few thousand heliostats (mirrors that continuously track the sun) concentrate sunlight onto a central receiver (a high-tech heat exchanger) that sits atop a tower. The central receiver heats molten salt at 290C, pumped from a "cold" storage tank, to 565C, where it flows to a "hot" tank for storage. When the grid load dispatcher decides electricity is needed from the plant, hot salt is pumped to a steam generating system that produces superheated steam for a turbine/generator. The salt then is returned to the cold tank, where it is stored and eventually reheated in the receiver to complete the cycle.
The salt storage medium is a common fertilizer, a mixture of 60% sodium nitrate and 40% potassium nitrate. It melts at 220C and is always molten in the "cold" storage tank. Molten salt is used because it is inexpensive and provides for efficient storage (99%); it is liquid at atmospheric pressure and its "hot" operating temperature perfectly matches the needs of today's high-pressure and high-temperature steam turbines. The molten salt is safe since it is nonflammable and nontoxic.
The collector field, salt storage capacity, and the receiver are optimally sized for the needs of the utility. In a typical installation, solar energy collection occurs at a rate that exceeds the maximum rate of energy consumption by the turbine. Storage tanks can be designed with enough capacity to power a turbine at nearly full output for 24 hours per day and up to 70% of the total hours in a year--as compared to 24% if electricity were only generated when the sun shines.
The readiness of power tower technology is illustrated by the successful completion of the Solar Two project in 1999 (see Appendix for Aug. 30, 1999 press release). Solar Two was a partnership between government and private parties to complete the development of solar power towers. Solar Two was the world's largest power tower, producing 10 MW of electricity with enough thermal storage to operate the turbine for three hours at full capacity.
Solar Two has mitigated the risk associated with the first commercial power tower plants now being offered for sale in four countries by proving that the technology is practical on a large scale. Solar power towers in the 10-400 MWe range can now be built--and indeed, design of the first plant in Spain is now underway.
10A. PRODUCT'S COMPETITORS (by manufacturer, brand name, and model number) The nearest solar competitor to solar power towers is solar trough technology [e.g., Solel (Israel) and Pilkington Solar (Germany)]. However, troughs do not have cost-effective thermal storage. Other grid-connected renewable energy competitors are photovoltaics, wind, hydro-electric, and biomass. We also compete with all conventional, intermediate load, and grid-connected electricity generating technologies including coal, gas, and nuclear. However, unlike our competitors, power towers do not emit pollution.
(table explaining effectiveness)
COST EFFECTIVENESS PERFORMANCE Electricity cost of 200 MW plant Installed cost of energy storage for 200 MW plant Lifetime of storage system (years) Annual roundtrip storage efficiency Maximum capacity factor of optimized system Annual solar to electric efficiency POWER TOWER SYNTHETIC OIL PARABOLIC TROUGH PHOTOVOLTAICS WITH BATTERY STORAGE $0.06/kWhr $23/kWhre 30 99 percent 70 percent 17 percent $0.12/kWhr $200/kWhre 30 95 percent 24 percent** 13 percent $0.25/kWhr $650/kWhre * 7.5 76 percent 24 percent** 10 percent (a
> solar panels (photovoltaics) are more effective with high-frequency radiation
No, as a matter of fact, they are not. When the frequency is higher, the excess energy is wasted
as heat. Not only is it not used, but it heats the panels and makes them even less effective.
Work has been going on for some time on panels that can use the full spectrum, or at least a wider
swath of it.
You don't seem to know what you're talking about.
I live a couple miles away from a big windfarm. There's no detectable noise, and the turbines turn very slowly-- maybe once every couple of seconds. It's actually quite relaxing to just sit and watch them spin.
As for birds, I admit that I'm no ornithologist, and I haven't done a population survey. But I've never seen a bird get hit by a turbine, even when they're flying around in big flocks. They don't even go near the things, unless they're cruising around near ground level to look for food.
There have been a few turbine failures since the windfarm was built, but never a grass fire. The one failure I witnessed looked pretty spectacular, with a bright flash like a shorted transformer, but no parts fell off. I have never seen nor heard of molten metal flying out of the things. (Perhaps you're confusing the term "windmill" with "iron foundry.")
- a "typical" residential system (2.4kW AC peak output) is going to run $9000-12000 after the state rebate
- there's also a 15% state tax credit
- the utility buyback of power is called "net metering" and they actually pay the retail price for the power (i.e. they credit you for power you produce at the same rate they charge you for what you use)
As to one of the original, unaswered questions: if you don't have batteries (and you don't need them if you are grid connected), the only maintenance required is hosing off the panels a couple of times a year. The panels are warranteed for 25 years, and generally good for much longer.
"Research is what I am doing when I don't know what I am doing." -- Wernher von Braun
For utility installation, you need capitalizations of at most $2000/kW (comparable to hydro and nuclear power plant capital investment requirements) - wind is there now, but solar has some distance to go to be usable as a utility power source. Currently solar photovoltaic systems go for about $2.00/PEAK Watt at best; given night time, solar angle, weather effects etc. and costs beyond the PV cells themselves, that translates to a $8000 to $10,000/kW capitalization requirement right now. PV systems have been dropping in price by about a factor of 2 every decade lately, so we have likely 30 years more development before they will be competitive at the utility installation level.
A lot of this information is available from the Department of Energy's Energy Information Administration.
On the other hand, if the cost of putting stuff in space was low enough, you would get peak watts all the time with a solar power satellite, so in principle that could be a feasible utility option in the near future.
Energy: time to change the picture.