Ted Nace, claims "Just 100 square miles of CSP installations would supply 100 percent of the U.S. electric grid."   Wow. and to think That Scientific American was talking about thousands of square miles of PV installations only in January.  Nace is either bucking to be world champion lier for 2008, or he does not understand the difference between 100 square miles, and a 100 mile by 100 mile square.   Rest assured Ausra's chairman David Mills talked about 92 miles by 92 miles which equals 8464 square miles not 92 square miles as Nace claims.  

Charles Barton

But of course with conservation power use could be cut in half, and wind could takeover 20% of what we now use.  40% after conservation takes hold.

Rooftop solar could do half of the reduced demand, leaving the rest for CSP installations and biogas from waste as ultimate backup.

That's more symbiotic, like natural rythyms of wind, sun, clouds, it works with nature.

Large centralized expanses of CSP taking over square miles of land aren't so symbiotic.  Try smaller CSP to power factories, from the roof and land surrounding the plants.   It can still power 10 or 20% of the new level of power consumption after conswervation kicks in.

With 10 or 20 square miles total, a half a square mile or quarter per factory site.  

http://amazngdrx.blogharbor.com/blog

PV does not equal CSP

PV or photo-voltaics are polycrystalline layered platters that only convert a portion (about 28%-30%) of the amount of energy that falls upon them.

CSP or Concentrated Solar Power, relies upon reflectors which to concentrate energy collected from a large area upon a central tube which superheats it and the liquid inside, which then powers a generator akin to the way that gas-fired steam turbine plants work.

PV's would require 1,000's of square miles to power the grid.

CSP's on the other hand are more efficient, and therefore would only require 100 square miles to produce the same amount of energy.

Make that 1000 square miles, one installation per factory averaging 1/2 square mile, on 2000 factories.  Well within the realm of practicality.

A 100 mile square equals 10,000 square miles.  Whoops.  One tenth, 1000 square miles of CSP, could power 10% of present power use, 20% of use after conservation.

http://amazngdrx.blogharbor.com/blog

Unfortunately.

CSP can refer to both Concentrating PV, and Concentrating SolarThermal.

CPV, CST would be better acronymns.

However CST, "Central Standard Time" is already kinda taken....

The relative efficiency of solar thermal vs. photovoltaic is only a factor of 2 or 3, not a factor of 100 or more. So yes, we would definitely need cover an area close to 100 miles on a side.

But that said, even that isn't really that much area. The US has an "impervious surface area" (roads, buildings, etc.) considerably larger than that, so it's well within the range of our capabilities.

I guess solar furnaces could have solar PV surrounding the heat receiver, to catch the inevitable leakage at the focus.  So that would make it solar cogeneration.

Like wise solar PV is much better fed by concentrated light and cooled to collect heat.  So solar cogeneration works on both applications.  And solar furnace mirrors can go over parking lots, on roofs, and even over highways.  

The hot desert regions have plenty of space and sun.  "Impervious surface areas" preffered!  Over wilderness land.

http://amazngdrx.blogharbor.com/blog

Thermal solar is up and working.  Has been for several years in California.

What would make it more exciting(?) for a lot of people is if there was a working plant with significant heat storage so that electricity could continue to flow after the sun sets.

I understand that there is one such plant being constructed in Spain at the moment.

But to appeal to the larger portion of Americans (many who think that no good ideas are to be found past our shores) a "see it here, now" project would make the system concrete and generate a more accepting climate.

Good question.  

Ausra (line focus) claims $100/m2, BrightSource (power tower heliostats) $150/m2, Matrix Solar Dish (me) $100/m2.  

All these leading solar concentrators have one to three year simple paybacks against oil and gas in Colorado type climates, double that in cloudy climates.  Concentrator lifetimes are 30 to 50 years with the new glass/silver/palladium/paint mirrors from Guardian Industries.  

Solar dishes have the edge on performance due to no cosine losses from directly tracking the sun in two axes, and due to small high-intensity point-focus receivers.

No new tooling requirements enable rapid global scale-up using existing commodities assembled with existing labor skills.

The only thing I ask is that these facilities are sited in good places, and that transmission lines can be built without screwing up the environment too much.

Take a look at the maps. Some areas get more sun, other areas are prone to floods, harsh winters, fogs, and hurricanes, not good for concentrated solar furnaces (CCF sounds good to me!). The transmission lines might be the weakest link in the system ... I think many are thinking about the desert Southwest here.

Solar concentrator furnaces are NOT a good idea in urban areas, IMHO.

Onward through the fog

Because we built one 25 years ago with 25 year old technology we shouldn't build one today with today's technology?

Is that what you mean?

Someone built an electric car prior to 1839.  

We shouldn't try that again?

Just not following your logic.

We've already got a HVDC line running from north to south along the west coast.  It was built to bring hydro-generated power to Southern California.

It sweeps east through western Nevada as it ducks around the Sierra.  Pretty close to some of those very sunny climes.

I hope we can eventually get beyond the mantra of power and use solar concentrators for what they are best suited for, displacing fossil fuels.  Applications include industrial process heat, preheating existing power cycles, commercial and residential HVAC, desalination, and so on.  Later, much later, we can do base load solar power plants.  

The value of solar concentrators is the value of fuel displaced.  Do the simple stuff first.

Tnrkitect wrote: PV's would require 1,000's of square miles to power the grid.

CSP's on the other hand are more efficient, and therefore would only require 100 square miles to produce the same amount of energy.

If we take that implied PV/CSP ratio to be at least 20 (2,000sqm/100sqm), and if we assume that PV has an efficiency of at least 10%, your statement seems to imply that CSP has an efficiency of at least 200%.

Is that really what you meant to imply?

GreyFlcn wrote: 335,000 square miles of "Warm Desert" in North America. Is that enough?

If Nevada Solar One is averaging ~10 MW/sqm, it would need to be scaled up to ~50,000 square-miles to cover the present average electrical market of the United States. As the United States electricity market expanded to 10 times its present size, the solar power plant would need to scale up to ~500,000 square-miles (but that little, only if all of those square-miles were as optimal as the first square-mile), exceeding all of the "Warm Desert" land area in North America.

As the United States electricity market expanded to 10 times its present size

Heh, and now you're just trying to be silly and difficult. :)

"CENTURIES AND CENTURIES FROM NOW WE MIGHT HAVE A PROBLEM! OOOOH."

_

By the time your nitpicking would even have any chance to come into play we'd probably be getting more desert.  (Good ol global warming, eh?)

Why would we be using first generation power plants centuries from now?

Why are we limited to only 1 technology?  PV for instance could be dirt cheap by then. Or Hot Rock Geothermal.  Or wave power.  Or fusion!  Or maybe we'll build us a super-cool dyson sphere.

SES in Oz cools with holding ponds.  Dry cooling at night is also an option.  High-intensity pv can be located near hot water loads.  Stirling dry cools behind the engines with large radiators.  Waste heat can also be dumped into oceans, rivers, aquifers, city water companies, sewage treatment, and irrigation.  Some propose using concentrator frames for dry cooling 24/7.

The water requirements, independent of heat source, are directly related to the high temperature in the cycle. The higher the temperature, the greater the cycle efficiency and the lower the (relative) amount of heat required to be removed by the cooling medium. Therfore, Coal requires a little less than nuclear and CSP is probably similar to coal (at least for the systems I've seen). If you have the operating temperatures of facility, calculation of the water requirements is very simple.

Dry cooling is an option but the ability to take advantage of the daily cycle (greater cooling at night) is probably not practical due to the great investment necessary in storage. Dry cooling is used for some conventional power stations and falls within the cost effective range.

The Palo Verde nuclear unit in Arizona is cooled by treating aste water from Phoenix which solves two problems at once.

I must apologize to Ted Nace for my remarks in the first post.  Ted stated to me that he was not at fault for the errors for which I criticized him.  According to Ted the errors were allowed to creep into his Gristmill post after he had submitted it to Gristmill.  

Charles Barton

The least expensive way to cool solar thermal in the desert is to use waste heat in a closed loop for desalinization. That is your condesor coils are in a closed loop, cooled by the liquid you are purifying.

You add capital costs - not just in your system but in the water purification plant. (Desalination is only one part of the purification process. ) But the clean water is valuable enough, especially in the desert, to lower your costs.

Re: Solar thermal in desert by Gar Lipow,

That is a beautiful combo.  Love it.  Can you say "pipeline from Gulf of California to Arizona border"?

-Christopher

Hey, this is a cool forum; there are actually people here who can think, and not many personal attacks.

Hey, I love Pangolin's idea of using this "waste heat" to power a desalinization plant. Re Chile, is it really sunny there? I've been to extreme southern Peru, near the Chilean border, and it never rains, basically, but there's nine months of fog per year. Weird. Guess the fog doesn't affect northern Chile?

I've been hooked up to a 3Kw PV  system for about five years. it's great, but I hope we can get systems for less money in the future. Meanwhile, I've been enamored with solar troughs for years. i'd rather give up EITHER 100 or 10,000 square miles of desert in exchange for all the benefits, e.g. have you ever flown over the eastern/central US, and seen the innumerable plumes of black smoke from the (coal fired?) power plants?

Wanna save time, money, and the environment? Support PRT (Personal Rapid Transit) Not hip to PRT? Google it!

Is the flogging of the anti-Euclidean intern in question on YouTube yet?

Chickens deserve our true friendship! So do fish! So do other sentient beings! Let us learn to be kind.