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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
then more power to 'em!
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?
Great idea, but power simply can't be distributed over that great a distance.
To make up for losses due to resistance in wires, they up the voltage to absurd levels -- decreasing the current level, and, in the process, the voltage drop over a long distance. However, this can only be taken so far, and towers supplying electricity to the rest of the planet is way too far.
In fact, I'm pretty sure that the continental US is too wide for coast-to-coast power sharing (that is, power generated in, say, New York, can only be "shipped" as far west as Indiana, or so).
On the other hand, replace today's wires with some kind of high-current, high-temperature superconductor, and you're golden.
...the US would takeover those sunny countries.
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.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
Will the sunshine nations (OSEC) collude to create artificial shortages and drive up prices in the sunless nations. Rolling blackouts, $700 power bills. The best part will be when they say its the fault of the sunless nations for having draconian environmental laws.
I'm really not this bitter in person.
"The plural of anecdote is not data." -- Roger Brinner
If governemnts subsidized people to install these instead of new shingles, this would severely cut down energy concerns.
Of course electric companies would complain, but they will still be needed, solar power won't provide enough power.
hmm...actually then my electric company would just charge more for less so they don't lose profits...damn
Gibble: Descriptive of an emotional state in which one's mind is scrabbling for some purchase on reality
ok so these people have a 17% electricity bill drop (from what to what in Japan?) after buying an 1100 sq. ft. home that has solar panels...
How much did having the solar panels on the home add to the price of an already expesive home? How much will the 17% save over the life of the home?
Are electric rates in Japan like they are here? 17% of my last electric bill (mind you, it's the summer and I have the A/C on at least 8 hours a day and a box fan in the bedroom on at least 10 hours a day) is $4.20 (granted my apt. is 720 sq. ft. instead of 1100).
International Power Sharing/Leasing/Selling is all well and good. However, I truely doubt that the large scale implied by the poster would ever happen. All cables are lossy. Pushing power along cables has energy lost, dependent mostly on how far you're pumping the juice. (Also, voltage, current, resistance of the wire, local EMFs, and all sorts of minor things too)
While it would rock to have clean energy finally adopted... Carting it across long distances still sucks.
Gimme Wind, Gimme Solar, hell, I'll even take Geothermal, just make it clean, unobtrusive, and if you'd like, I can sell you some good land in my back yard. *me mutters about pretentions NIMBY asses*
I assert that my comment is only my opinion, not that of any employer, past, present or future.
I'm sorry, I can't help but smirk and snicker when I think about the Japanese and their
"Solah Powah Towahs!"
*smile*
---"What did I say that sounded like 'Tell me about your day?'"---
We don't really need lines carrying solar power from sunny areas to the rest of the world. There are plenty of environment-friendly ways to generate power; solar in the sunny areas, hydro-electric in areas with lots of waterfalls, etc, windmills in the plains...
Availability of methods isn't slowing down alternative fule sources; people just see no reason to invest the necessary capital to change over, when burning dead dinosaurs is working quite happily.
Thomas Galvin
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!
It requires a complete re-think of the utilities infrastructure and removal of idiots that run them.
If a normal neighborhood had 2 stationary panels on each home's roof pointed south that backfed to the utility power and they did the storage, it could be a reality right now.
but it's easier to keep that 1929 Coal plant running and those power commisioners that have no fricking clue or care outside their pocket or circle of power than to change to current technology.
Anyone here can easily reduce their power consumption to 1/10th of what they use now. Couple that with a city wide solar network with some wind plants like in Macinaw city or out west and you can easily have clean power.
it's changing government, and the wasteful companies (running 1500 horse power pumps from 1955-1957 instead of buying noew high efficency pumps) that will be nearly impossible...
Changing to non polluting power will be more difficult than getting bill gates to embrace and use linux.
Do not look at laser with remaining good eye.
Another obvious stirling use is as part of your home heating plant.
British Gas to launch individual CHP boiler for homes
British Gas has announced that it is developing a household boiler that generates both heat and electricity, which will increase energy efficiency and cut costs for customers, allowing them to sell excess electricity back to the Grid.
The new combined heat and power (CHP) boilers, developed by MicroGen Energy
Think about it. You burn gas to stay warm. (if you don't have a heating season....then you don't) Why not burn the gas to do work? You still get your heat. And the work can make electricity.
Australia is building big convection towers. They are just a big (big!) greenhouse sloping up in the center, so the hot air runs up what amounts to a chimney there, and drives a big windmill -- really, a bunch of them -- in the chimney. It has only a few moving parts, and is easy to build with mature technology.
Simple might not help employ physicists, but it's the right way to build.
You know, the author of the article would have more crediblity if he quit using phrases like "Berlin Wall of Solar Power" in the article.
Also buried in the article is the fact that this rig is so freakin' expensive to set up and so uneconomic to run, that only nations with massive subsidy programs are the ones looking at it. They are targeting Spain because they signed Kyoto and so the government (read taxpayer) is willing to underwrite the whole thing.
So, who wants to take bets on how long before environmentalists scream that we are destroying the planet by planting hundreds of thousands of square miles of mirrors across the Southwestern desert?
Have they figured in the cost of replacing sandblasted mirrors and the cost of trucking water in to clean the mirrors?
You can tell a great deal about the character of a man by observing those who hate him.
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)
Solar insolation is about 1kW/m^2.. Well, except for the earths rotation. Assuming a non-tracking system, we have to divide by a factor of pi, so thats 300 W/m^2.. Well, except that the average efficiency of solar cells is under 15%, so thats 45W/m^2. Now, the average home has what? 2 people in it, and the per-capita electrical usage, averaged over the course of a year is 1kW. So, you need 2kW for that home, and only get 45W/m^2. So, you need 50 square meters of solar cell, correctly angled south. And this is the best case.
Now account for clouds and dirty cells. Unless you clean the cells every few days and pressure wash them biweekly, better increase the square meters of solar cells another 50%. So, thats 60-80 square meters of cell/house..
Now the next question. Where do you store all the energy you'll use at night? If you don't store it, where does it come from? Fancy burying a few ton flywheel in your backyard? How about aa closet filled with lead and sulpheric acid batteries? If you're going to use hydrogen to store it, better double or triple the square meters of solar cell for those inefficiencies.
The same problem applies to 'Solar 2'. You need about 1000 of them to equal the average energy of a nuclear power plant. And another 299000 to equal the mean energy used by the US. To replace all energy used in the US requires about a million Solar 2's.
Let's assume we want to provide all of the world's energy needs by solar power. If I recall correctly, the world currently uses about 500 exajoules of primary energy per year, or about 16 terawatts. The sun provides about 1000 watts/m^2 at our distance. However, the overall system efficiency would be somewhere around 1% of that (say 20% solar cell efficiency, 75% loss from night/day/latitude geometry , 40% weather loss, 70% storage conversion and transmission loss). That gives 10W/m^2 average output, so we need 1.6 million square kilometers, about the size of Alaska.
That sounds bad, but it's actually only 0.3% of the earth's surface area. I would guess that the best way to implement that much collector would be to develop plastic based collectors in huge sheets that are floated on the oceans. Convert the energy to hydrogen on site and pipe it to the consuming countries. By eliminating fossil fuel usage, you free up huge sources of raw materials to make all of that plastic.
You could argue that that much area would screw with the earth's climate by changing reflectivity. However, at least it's not generating a layer of greenhouse insulator. Moreover, current agriculture practices alter the reflectivity of a much larger percentage of the earth's surface.
(Don't bother replying to suggest outer space collectors. Say they were 30X more efficient than earth-based systems. Nobody's going to launch satellites with a surface area 3% the size of Alaska. We've been trying to put up a space station the size of my back yard for 20 years now, and still haven't finished.)
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.
Let's see. The article talks about 200 MW plant. At 1kW/m^2 and 17% efficiency this means we need about 300 acres of mirrors. Seems real practical.
You're missing the important point here. It's not that solar power is going to save the Japanese a lot of money. They're desperate to ween themselves off nuclear power using any means necessary. After all, if you had to contend with these three smashing your reactors on a yearly basis, wouldn't you be damn anxious to do something -- anything -- to stop relying on nuclear power?
GMD
watch this
Looking at our electrical bills over the last year averaging between $100 and $150 a month, I decided to look into putting in solar panels and here is what I found out.
For 7K out of pocket (after tax credits, rebates, etc.), I can get a 2KW solar panel system with grid tie installed. This would give me, conservatively, about 496 KW hours a month in production. This would cut my usage by 2/3s. For 12K out of pocket, I can get a 3KW system which would give me about 720 KW hours a month in production and would completely clear my needs.
With a grid tie system, I run my meter backwards when my production is greater than my demand. This means that any electricity that I generate is credited against my bill at the rate in play (I believe you also get peak pricing withi this setup) at the time I generate it.
Bottom line, is that for a 12K investment, I can clear an average bill of $150 a month. This means that in a little over 6 1/2 years I have paid off the system. Or you can think of this as giving me an annual return of 12.5% on my initial investment. That is pretty damn good!
> 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.
- 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
Well, There's always a chance someone on Slashdot doesn't know this, but... Global Warming / Cooling is junk science. The proponents have blocked appropriate measures of earth's temperatures, which involve measuring the ocean's aggregate temperature, and have done so for about a decade now. The measurement would have involved a solitary underwater explosion, and the sound wave would determine the ocean's temperature (although salinity has an effect, it is far from a trivial science). This would be a tremendous mass of ocean water.
The "Save the whales" crowd resurfaced decrying the untold damage to aquatic life by doing this, which is ridiculous compared to doing nothing to find out what is happening to our planet.
Air temperature measurements are a waste of time, especially in urban areas, which have an elevated measure of heat because of the asphalt roofs, roads, etc. Measuring the ice caps is also silly, because their size changes seasonally, like with weather cycles. Everyone remembers the Halloween blizzard in Minnesota. And the 65 degree day in late December 15 years later. The only useful measurement would be of a volume of water (not a tiny pocket of air) the size of the ocean, at the equator. But that's being blocked bye environmental activists; they must have something to hide; what's a few deaf gray whales if it will save the planet?
Did you bother to mention that the various "greenhouse gasses" are mere precursors to tropospheric ozone, which is the hazardous smog that is discussed at the Weather Underground ? All of the sudden, ozone is bad and good.
I read a statistic once that in order to be entirely solar with our power, we would cover the earth 11% over with the dumb cells. Considering the nasty chemicals involved in the manufacture of solar cells, and that solar cells are not simply recycled, and fail in a decade or so (fragile materials), I can't imagine why any earth-first crowd would want yet another major source of toxic waste.
I have long thought that the only solar cells of any use on our planet (since the stuff in space is pretty handy, I'll admit) are the green ones in my lawn and garden. They produce oxygen, which every living animal needs. If you live in a newly developed neighborhood (like in suburban USA), the best thing you can do for your environment is plant plenty of trees on your lawn. Sure, it means raking, but in my neighborhood, I have 100+ year-old oak trees, and they are positively enchanting. They keep the sun off my lawn so I don't have to water, and they keep the sun off my roof (remember, these are mature oak trees) which reduces my AC costs. McDonalds passes out seedling trees on Earth Day, so it really doesn't cost you anything. Sure, it'd make more sense if they passed them out on Arbor Day, but no one remembers when that is, despite it being the more venerable day of commemoration by a good century or more.