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I think the better way of putting it would be "$0.20 / watt, amortized over 20 years." Typically, they talk these days of $3-4 / watt of PV capacity. In other words, a 1 kW PV array will cost $3,000 - 4,000 (that's just the panels; inverters, batteries, etc. are extra). Where I live, we average 6.5 hours direct sunlight / day throughout the year. Consequently, if I have a 1 kW PV array, I can average about 6.5 kWh of electricity / day. 6.5 kWh / day x 365.25 days / year = 2,374 kWh / year.

Incidentally, we also pay about $0.075 / kWh around here. That 1 kW PV array would save me about $178 / year. If I can get PV equipment for $0.20 / watt, which is what they're talking about in this article, that would be about $200 for a 1 kW array; it would take me a little over a year for the savings on my electric bill to pay for the PV. Right now, the payoff is in on the order of 20 years. This would constitute a VERY good reason to go ahead and make the investment in PV.

How much sunlight do you get? Take a look at NREL's maps and see for yourself. Multiply the number of hours of sunlight you get (according to the map) * number of kilowatts the PV array provides, and you can get an idea of the number of kWh you could get. Minnesota gets less than we do (Missouri), but not as much as California. Considering the fact that electricity cost > $0.20 / kWh in some places in southern CA, you can understand why some people out there are already going this direction (for some of them, the payoff is

When a utility company invests in such equipment, they typically amortize the cost over 20 years. Consequently, if it costs $3,500 / kW of PV capacity, the area provides 6.5 hours direct sunlight daily, and it does it for 20 years, that would be:

$3,500 / (6.5 * 365.25 * 20) = $0.0737 / kWh for the current technology

$200 / (6.5 * 365.25 * 20) = $0.00421 / kWh for this tech

Which would you rather pay on your electric bill?

"Many people look at solar as if its some sort of panacea, but the amount of energy that goes into making a tile is far more than you'll ever get out of it"
I too once spouted this myth
But after some serious googling one day I could only find sites which disagree
Of course most of these sites have a vested interest in the future of solar energy, but I didn't find a single site which backed up the claim about pollution, and given the stakes in the energy game, I assume that Big Oil(tm) or Big Windmill(tm) would have made it easily available.
Sam

A couple comments on yours. You make some excellent points.

NREL typically rates "one sun" of solar flux as approx. 1 kW / square meter. Typical solar panels are, as you state, about 15% efficient. If you want an idea of how much solar flux your area gets, take a look at the maps from these pages.

The best hydrolyzers (electrolysis units) are about 60% efficient. Since a kilogram of hydrogen contains about 33 kWh of energy (if you convert at 100% efficiency), a 60% efficient hydrolyzer will need about 55 kWh to make one kilogram of hydrogen. A kilo of hydrogen has roughly the same energy content as a gallon of gasoline. Consequently, if you're going to burn hydrogen in your ICE vehicle, you'll need 55 kWh of energy to replace one gallon of gasoline. In case you're interested, that's about 14 LITERS of liquid hydrogen (density = 71 grams / liter); no other commercially available hydrogen storage can match LH2 for energy density (yeah, there are some experimental systems which have been announced, but none of the COMMERCIALLY AVAILABLE solutions are anywhere close). Go find seven 2-liter bottles of soda (or which used to contain soda), and consider hauling that volume around to replace 3.785 liters of gasoline. Any question why they're having such a hard time storing a significant amount of hydrogen?

Last, but not least, most of your mobile fuel cell stacks are only 40% efficient. That beats the ICE's by at least 50% (last time I checked, none of the ICE's are beating 25% efficiency). Let's see, 60% effeciency at the hydrolyzer, and 40% efficiency at the fuel cell equals (0.6 x 0.4 = 0.24) 24% of the electricity you fed into the hydrolyzer actually coming out of the fuel cell. Talk about wasteful.

By the time you consider how little fuel you'll be able to store, you might as well just build yourself a battery-driven electric vehicle. The GM Impact/EV II gets about 6 miles / kWh. It has a range of about 96 miles (works out to 16 kWh storage). Over 75% of the energy fed to it comes back out; beats the hell out of 24%. Also, considering the price you'd pay for the fuel cell stack (Toyota's Fuel Cell Vehicle is quoted as costing $250,000 per unit to build; they lease them, not sell them), you could probably buy NIMH or Li-Ion batteries and get some pretty impressive range.

Any argument for a fuel cell vehicle is a bigger argument for battery electric vehicles. Safety issues aside.

More details here

Well, it's a tricky figure, because manufacturers usually don't release their manufacturing energy costs, but using the simple calculator on this site, a 190 watt panel in LA with no tilt will produce about 6500 kWh per year.

At 130000 kWh over a (conservative) 20 year lifespan, I'm guessing that their production *far* surpass the energy used in their manufacturing, installation, and design.

Grrr...the other persistent canard. = ) As of 1999, it was down to something like 4 years, in an exceedingly conservative and comprehensive calculation:

http://www.nrel.gov/docs/fy99osti/24619.pdf

And the panels themselves are usually output-waranteed out past 20 years (30 years being a safe bet lifetime for most.) Though I suspect that since we're seeing steadily more automation in the newer plants (and less silicon per watt, and better per-square-meter efficiencies, that this has even gotten better recently.

Photon International goes over these issues in some detail...

I don't know enough about what Canada has to offer, so this is limited to the U.S.

When folks around here say they're "going backpacking" they usually mean they'll be hiking in the wildnerness with just what they can carry on their back. Such trips rarely include visits to bookstores, musea, and other geek centers. Such trips are best in mountainous areas -- I can't imagine backpacking in North Dakota, for instance -- and can be done on a pretty low daily budget (but make sure you invest in high quality boots, tents, etc.). Some folks have mentioned the Appalachian Trail, which spans from Vermont to Georgia. On the other side of the country are lots of swell backpacking areas from the Rocky Mountains west. The national parks in Utah and Arizona (Canyonlands, Staircase, Zion, Grand Canyon, etc.) are especially popular for such trips, though if you've spent much time in the outback you may be sick of such a climate (though the terrain here is more impressive). Almost any national park or national forest is a good backpacking experience, and entrance fees (especially if you get a year-long pass) are astonishingly cheap.

Unfortunately, you'll be arriving at the tail end of good backpacking season. Beginning in late September you can't trust in a lack of snow anywhere inland in the northern two thirds of the country, though places like southern Arizona are quite enjoyable. Unless you're staying until late next spring, you should hit any outdoor areas in the north first and work your way south.

Unfortunatey, U.S. public transportaion leaves much to be desired. There's nothing like a Eurail pass, and Amtrak stops mostly in larger cities, which is sad, because trains played such a large part in building America. Greyhound has excellent coverage and fairly reasonable rates, but if you're going to a lot of places, your pocketbook could take a big hit. Finally, hitchhiking across the country is probably no longer a viable plan, but it may be invaluable in a pinch. Hitchhikers are, generally, assumed to be dangerous until proven otherwise. On the plus side, most cities have a bus system decent enough for tourists to enjoy the town.

Unless you have access to a car, my advice is to pick a handfull of (relatively small) areas you want to visit and then figure out what all the great things to do there are.

Some geeky things in my neck of the woods (Boulder, Colorado): National Institute of Standards and Technology (home of the most accurate clock in this hemisphere) is right next to a branch of National Oceanographic and Atmospheric Association and a beautiful two-hour mountain hike away from the National Center for Atmospheric Research. They've all got free tours and such, though I haven't taken one since security got tightened after 9/11/01. About 10 miles south of town is the National Renewable Energy Laboratory and more beautiful mountain hike areas. 30 miles or so to the north west is Rocky Mountain National Park, which gets pretty cold in September and later. Denver, CO has Forney Museum of Tranportation and also the nation's only major airport built in the last 20 years, so it's full of neat engineering bits.

Your post sounds quite ambitious, and there's no way you can really experience all of what's neat in America in even a year, so find some of it and enjoy the hell out of that! Cheerio!

Why aren't these billionaires exploring the depths of the oceans as James "King of the World" Cameron does?

Surely there's interesting stuff down there, like nucular radiation-enlarged squids, slime monsters and maybe a Godzilla-like creature or two.

Are any of them funding research into solar cells, wind technology, tidal power or geothermal or is it all a great big ego boost?

My mistake. The article I read says that "the state of North Dakota alone has enough energy from good wind areas to supply 36% of the 1990 electricity consumption in the lower 48 states."

Still, that's pretty damn good. And there is a whole other Dakota too!

It uses about half of the created energy (through a normal Carnot cycle) for pumping (about 120kW). The other half is not quite competetive, but with the nutrient rich and cool water, fish farming and air conditioning can be done, heaving the whole investment to a black zero (or better).

I leave the exercise of finding the link to a Karma-hungry reader.

More info here, and here

And an OTEC history here

Years ago in my Thermodynamics class, I believe we discussed something along those lines. It was called OTEC - Ocean Thermal Energy Conversion.

Here's the page with the quote you cite. (Search for "hydrogen production".)

"Algae are used to separate hydrogen from water to produce clean-burning hydrogen to power vehicles and power plants. Because algae are not inherently proficient at this process, researchers genetically engineer algae to more readily produce hydrogen."

Foremost among the production methods being considered is what has become known as solar hydrogen. Solar hydrogen refers to any method of production that uses the power of the Sun to produce and collect usable hydrogen. This can be accomplished by various methods. The most likely approaches are:

* Energy collection by solar "gensets," parabolic solar collectors that focus and concentrate the light energy of the Sun
* Applying the collected energy to a Stirling-cycle heat engine, which in turn drives an electricity-producing generator to power an electrolysis system
* Using the heat from collected solar energy to "crack" hydrogen directly from hydrogen bearing sources like water, natural gas, and organic bio-mass, such as municipal and agricultural waste.

"Algae are used to separate hydrogen from water to produce clean-burning hydrogen to power vehicles and power plants. Because algae are not inherently proficient at this process, researchers genetically engineer algae to more readily produce hydrogen."

There are certainly ways to produce hydrogen without resorting to burning fossile fules. The US Governement has spent close to $800 million over the years to prove that Ocean Thermal Energy Conversion (OTEC) works. This is a non-polluting, sustainable way to produce energy which can be used to extract hydrogen from water.

As it isn't using oil or nuclear power, it is currently out of favour with the US Department of Energy, but you should certainly learn more about it. A good overview can be found at the National Renewable Energy Laboratory and the latest news can be found at OTECnews.

Come on, now. Old "facts" that seem very appealingly counter-PC, but they don't hold up.

1. Solar photovoltaic energy payback - Nope, afraid the facts don't back you up. Old meme advanced by conventional energy interests in the 70s. This study has been held up very well by the recent production survey data.

2. Solar photovoltaic toxic waste - well, it is after all a wafer of n and p - type doped silicon with conductors etched into it, and that's not like any other manufacturing we do....oh....nevermind.

3. Solar thermal plants (based on SEGS I - IV and the Boeing Rocketdyne Solar Two / Solar Tres plants) have a typical Rankine cycle thermodynamic efficiency for their temps. The difference between them and a coal plant's thermal / electric efficiency is that one runs on free fuel. (Though construction as of now is quite pricey, it's pure inexperience - these things are not that complicated. After all, there's 354 MW (yes, that's megawatts) worth powering California.

4. Windmills need to be seperated by about 2 rotor diameters left - to - right and 1.5 RD in between rows. A megawatt- class turbine has a ca. 80 - 100 M rotor and powers ca. 400 (US) homes. Not a crippling amount of space by any means....look at turbine penetration rates in Denmark, for instance.

By the way, this entire problem is a canard and has been for a long time.

Current residential / commercial solar cells have an energy payback time of ca. 20 months and a useful (warranteed, in fact) lifetime of 20+ years.

This is one of those damaging "fact" memes that has no backup - a relatively current report (whose projections have held up pretty well,) can be found here.

My thought when I first read this was not memories, but high efficiency (>85%) solar cells.

The folks working on optical rectennas are to the point where their remaining problems are with making metal-insulator-metal tunneling diodes that are small enough and fast enough.

They are close to demonstrating a working device, and it looks to me like DNA scaffolding could not only make it easier to build the MIM diodes, but might make fabrication of the entire device easier and faster. Instead of ion-beam implantation, you grow the 2D crystals in a vat.

The idea is to make an array of tiny dipole antennas, with a diode at the feedpoint. When light hits the antennas, an AC current is generated, then rectified by the diodes.

Making the antennas has been possible for some time now (500 nanometers). The work on making the diodes is nearly ready. Now it looks like we have a possible cheap and efficient means of constructing them on a large scale.

This tech is much older. Take a look at this article (note: it's a .pdf file). I first read about this stuff in 1993. Texas Instruments started developing this 1983 (yes, that's two decades ago), finally abandoned it and licensed it to someone else.

For much of the last month or so, I've been studying techniques for accurately predicting the position (and some other parameters) of the sun at any given time of day and then setting up experiments to verify the results.

(It's not exactly fun work, especially having to get up at 5 am to prepare for the 6:30 sunrise measurements.)

The wobbles you see probably can be attributed to being off by a minute or so in taking each of the multiple exposures.

The diamter of the sun is about 0.5 degrees (31.48' according to the page accompanying the image). A one minute delay in taking the shot will mean the sun has moved (for example on 5-1-2002) about .3 degrees in azimuth, and .16 degrees in elevation. It's also possible that the camera itself was slightly mispointed (nudged? wind? who knows?)

There's 41 images taken between January 12 and December 21, all supposedly at 10:28:16.

The sun would start at (149.99,22.53) (azimuth, elevation), move upward and to the left in time until June 12 where it reaches (112.84, 60.88) and then starts to move downward until June 27, where it reaches (111.64, 60.47) and starts to swing back toward the right, until November 27 (152.86, 25.75), where it'll start swinging back to the left until his last position at (151.55, 22.72).

The sun would have reached it's "lowest" point in 2002 on 12-28 at (150.59, 22.48).

I originally thought the wobble might be due to atmospheric ("optical air mass") refraction variation due to tmperature and barometric pressure, but at those elevations, those effects turn out to be negligible.

This program from NREL will let you calculate the position of the sun and some of the properties that affect its perceived position. If you don't want to compile a program on your machine, you can check out the a href="ssd.jpl.nasa.gov/horizons">web-based "ephemeris" calculator from JPL.

If Santa Clara wanted to build its own turbines, it could probably enter a joint agreement with nearby Santa Cruz county to build turbines on the western ridge that separates the valley from the Pacific Ocean

Heh, you haven't lived in Santa Cruz, have you? The environmentalists would have a heart attack at having the western face of those hills scarred by modern man. Its difficult enough already to get a building permit for a home facing the ocean there, I seriously doubt a large wind farm would make them anything but livid.

Looking at a wind map, I see that the highest wind power density local to Santa Clara is not costal but within hills separating San Jose from the Sacramento Valley. The Carquinez Straits north of Oakland appears to be good location, as is Altamont Pass (yes, already utilised). In addition, Pacheco Pass to the southeast is comparable to the coast, and probably would make environmentalists happier. The most outstanding sites in California actually appear to be in the mountains on the eastern border, with many category 6 sites. The problem with those sites is complete inaccessibility during the winter, which begins early and ends late there. (Data from the northern california wind power map and generally from the Wind Energy Resource Atlas of the United States.

As far as them spoiling the landscape, I personally find most large wind installations to be quite beautiful, but I'm wierd that way. There are places I wouldn't want them that way, mainly because I appreciate a particular inherent beauty in those areas that would be marred by the lines of windmills.

Also, I currently live in upstate NY. Personally, if wind power were able to be installed and serve at least 60% of New York's power needs, I'd have to think long and hard. There are some ridges in the Catskills which would produce an amazing amount of power, as well as some points in the waters off Long Island which wouldn't be half bad either.

If Santa Clara wanted to build its own turbines, it could probably enter a joint agreement with nearby Santa Cruz county to build turbines on the western ridge that separates the valley from the Pacific Ocean

Heh, you haven't lived in Santa Cruz, have you? The environmentalists would have a heart attack at having the western face of those hills scarred by modern man. Its difficult enough already to get a building permit for a home facing the ocean there, I seriously doubt a large wind farm would make them anything but livid.

Looking at a wind map, I see that the highest wind power density local to Santa Clara is not costal but within hills separating San Jose from the Sacramento Valley. The Carquinez Straits north of Oakland appears to be good location, as is Altamont Pass (yes, already utilised). In addition, Pacheco Pass to the southeast is comparable to the coast, and probably would make environmentalists happier. The most outstanding sites in California actually appear to be in the mountains on the eastern border, with many category 6 sites. The problem with those sites is complete inaccessibility during the winter, which begins early and ends late there. (Data from the northern california wind power map and generally from the Wind Energy Resource Atlas of the United States.

As far as them spoiling the landscape, I personally find most large wind installations to be quite beautiful, but I'm wierd that way. There are places I wouldn't want them that way, mainly because I appreciate a particular inherent beauty in those areas that would be marred by the lines of windmills.

Also, I currently live in upstate NY. Personally, if wind power were able to be installed and serve at least 60% of New York's power needs, I'd have to think long and hard. There are some ridges in the Catskills which would produce an amazing amount of power, as well as some points in the waters off Long Island which wouldn't be half bad either.

Want to use the Minnesota "payoff time" information to see whether you want to plant a windmill? Use National Renewable Energy Laboratory maps.

Well birds have been chopped up in these things so it's no use pretending it's not a concern. That's why the U.S. DOE initiated research into the environmental impacts of wind farms and attempted to identify the optimal locations for wind farm placements.

The National Wind Technology Center has a pretty thorough collection of research on the topic, which you can access here.

And about "polluting the visual environment," yeah that sounds dorky, but it's the kind of argument you hear in opposition to wind farm proposals in places like Nantucket. Personally I think they're kind of majestic, but that's just one man's opinion. Supporters of renewable energy really need to have some ready answers for these kinds of arguments.

...a lot of the renewable, or green energy policies have been put on hold.
You can read about renewable, or green electricity in this great report Green Power Marketing Abroad: Recent Experience and Trends from NREL'sGreen Power Network.
For lots of technical info on wind power, check out National Wind Technology Center which has a good online library.
The Danish Wind Industry Associationhas a lot of great info about Denmark's tremendous growth in wind power.

Just a note ahead of time. Some of the cars listed below are only available in certain parts of California and are only available in relatively low numbers.

Pure Electric:

2002 The Nissan Altra EV (pilot?)
2002 Ford Thi!nk City
2002 Toyota Rav4-EV
2002 Lido Motors Lido
2002 Ford Ranger EV (fleet only?)
2002 Nissan HyperMini (pilot only?)
Selectria Force (out of production?)

Hybrids:

2003 Honda Civic Hybrid
2002 Honda Insight
2002 Toyota Prius

Web Sites of Interest:

EV World
US DoE Alternative Fuel Car Buying Guide (many listed)
US DoE Alternative Fuel Vehicle Listing (many listed)
California ZEV Buyers Guide

How many people can hold the handle that turns the crank? Or in modern terms, how much juice can you reasonably throw at these beautiful monsters!?

So with this in mind, I don't think it's too off-topic to mention this article which talks about the gutting of funding for fuel cells. Or this student research paper site which talks about the inherent economy of different sources of energy in various terms. (Warning! They are pro-nuclear, so YMMV!) Also, if you are interested in where this topic takes you you should stop off here to follow up on whatever takes your fancy as far as energy production goes. They've got a veritable mountain of info. Check out their hydrogen economy stuff.

Whoever thought up the names of the two machines needs to get a grant or something! Green Destiny, mmmmmmm! Q, grooowwwl!

I can't believe the arrogance of this poster! There is so much work that is being done in this area, and this geek thinks he can just solve all the problems while goofing off at work? Before you or anyone wastes any more time, please take a look at a small sample of the good info that is already out there: Tons of info!,DOE's Hydro Porgram, The old shut down coean thermal program, and a good survey from the CA energy commission.

It's a shame that electrochromic windows haven't taken off. I first read about them in Popular Science, probably about 10-15 years ago, and if I recall correctly, they were used in a concept car by Ford (I could be mixing two Popular Science articles together), but they allow you to electrically darken and lighten windows, and they actually reflect light and heat (unlike liquid crystals, which just scatter light and heat but still let them through). I'm not sure, but they might also be wavelength-independent, i.e. reflecting all colors of light equally. The obvious barriers to their widespread adoption are probably cost and the ability to make panes large enough to use as windows.

By using the atmosphere of Mars to slow down the spacecraft in its orbit rather than firing its engine or thrusters, Odyssey was able to save more than 200 kilograms (440 pounds) of propellant. This reduction in spacecraft weight enabled the mission to be launched on a Delta II 7925 launch vehicle, rather than a larger, more expensive launcher.

No small feat, there. Too bad they didn't use regenerative aerobraking—we might have gotten the spacecraft back.

This isn't some new miracle pulled out of the hat by the Japanese. For example, an MIT Technology Review article on some American work on a methanol fuel cell is here. A whole bibliography on recent Direct Methanol Fuel Cell (DMFCs) work is here.

You've launched a rather incomplete assault on renewable energy sources here. Yes, large-scale hydro is no longer an option -- it causes too much harm to existing ecosystems, and there aren't many places left to put big dams anyway. And yes, wave- or tidal-power collectors or ocean thermal taps cannot produce large amounts of power without huge pieces of machinery. But you've skipped right over the renewable technologies that are actually being installed today -- wind and solar systems.

Wind: "Good wind areas, which cover 6% of the contiguous U.S. land area, have the potential to supply more than one and a half times the current electricity consumption of the United States." And the wind turbines being built today can capture this energy at about the same cost as operating a natural gas turbine or a coal plant, and less than half of the cost of nuclear power (wind has no fuel cost, so all of the cost of power comes from paying off the original investment in the equipment).

Solar: Enough sunlight strikes the U.S. to meet our electricity needs 700 times over. Solar cells are currently quite expensive to manufacture, so their power costs more than coal or gas. Unfortunately solar cells are now caught in a catch-22. They could become the cheapest power source in the world, but not until they are manufactured in really high volume, and that's not happening because they're so expensive. (We all know what happens when you start manufacturing silicon chips in high volume...) Although they're not there yet, prices are falling, and solar cells will become the preferred energy source eventually.

The great thing about photovoltaic cells is that they let us get our electricity from a huge fusion reactor that is conveniently located 100,000,000 miles from any population center.

P.S.: Solar cells have an energy payback time of 1-4 years, so they produce 8-30 times more electricity in their lifetime than they require to manufacture.

Dude, you're stomping on my idealism!

Seriously, I like your solution. Anything which is used as an excess luxury doesn't deserve to be kept cheap, but that which is truely needed (for now) shouldn't be artificially taxed (but nor should it be subsidized).

And prehaps my knowing several people at nrel has something to do with it...

FYI: The url is http://afdcmap.nrel.gov/nrel/
________________

" Research conducted in these labs is aimed at producing biodiesel fuel from microalgae and other plants. Biodiesel fuel is made from oils and fats found in microalgae. It can be substituted for diesel fuel or used as an additive. Biodiesel generates fewer pollutants than typical diesel fuels.

Quoting what I found to be the more interesting part of the page:

1. Typically, microalgae are grown in ponds, harvested and the oils extracted. The extracted oils are chemically reacted with alcohols to produce diesel fuels. Research in the laboratory is directed towards genetic enhancement of the fat and oil content of the algae to make the biodiesel fuel product more cost-competitive by 2010."

This is just the sort of thing I want to hear. Embed those puppies in my skin! I want to be green and foodless by the year 2020 goddammit!

But seriously, this is great news. Considering the shamefully small amount of money that goes into researching renewable sources of energy, I'm always delighted when they hit a new breakthrough. Solar is especially attractive - imagine running your entire home off a refrigerator-sized panel adhered to the roof. Total personal independence!

Unfortunately, there are severe limits at the moment. I recently looked into roofing a home with solar panels. Turns out that it would cost around $20k to be self-sufficient (and then only just barely). I worked it out, and it seems that with my monthly electricity costs, it would take me 103 years to pay that off.

http://www.mcn.org/a/mendom otive/Products/Unisolar2.htm

The trouble is that even the theoretical output of solar cells is low. It's bounded severely by the surface area because of the limitations of the diode materials available to us today. Turns out that even if you have full light shining on the surface, you can only get about 29% efficiency - and that's theoretical. In reality, it's less. Here's a site that explains the technical details:

http://www.nrel.gov/ncpv/documents/ pvpaper.html

Now, I have heard some clever ideas for increasing the efficiency. For example, one team discovered purely by accident that they could increase surface area by making the silicon layer extremely "spikey" on a microscopic level. The sunlight bounces around inside the spikes and is more likely to ultimately by trapped by a cell.
I think the theoretical number they cited was 40% efficiency, but right now that's still vaporware.

I wonder whether some slashdotter is brave enough to post the original ACS paper. I don't have access. I'd love to see what efficiency numbers these people are touting. Anybody?


-konstant

True, though I doubt houses use 100 amps 24 hours a day!

Most current and new houses, and appliances (yes, PCs are guzzlers, but Netwinders and Laptops aren't) are based on the assumption of cheap power. Off-grid solar houses of today use MUCH less power, which is obvious when you consider the solar panel cost of driving the typical energy-inefficient house of today.

Some solar installations are designed to supply high peak power through more batteries -- it's not unusual for a solar home to be able to power all typical shop tools, but maybe not all at once. Ideally one can use "the (solar) grid" to supply the high peak power demands.

I'm no expert so check it out: Home Power Magazine, www.crest.org, Nation Renewable Energy Laboratory.