Massive Solar Tower to be Built in Arizona?

SquidInk · Post by **SquidInk** » 07-27-2011 09:15 AM

An ambitious solar energy project on a massive scale is about to get underway in the Arizona desert. EnviroMission is undergoing land acquisition and site-specific engineering to build its first full-scale solar tower - and when we say full-scale, we mean it! The mammoth 800-plus meter (2625 ft) tall tower will instantly become one of the world's tallest buildings. Its 200-megawatt power generation capacity will reliably feed the grid with enough power for 150,000 US homes, and once it's built, it can be expected to more or less sit there producing clean, renewable power with virtually no maintenance until it's more than 80 years old. In the video after the jump, EnviroMission CEO Roger Davey explains the solar tower technology, the Arizona project and why he couldn't get it built at home in Australia.

[...]

Enviromission's solar tower is a simple idea taken to gigantic proportions. The sun beats down on a large covered greenhouse area at the bottom, warming the air underneath it. Hot air wants to rise, so there's a central point for it to rush towards and escape; the tower in the middle. And there's a bunch of turbines at the base of the tower that generate electricity from that natural updraft.
It's hard to envisage that sort of system working effectively until you tweak the temperature variables and scale the whole thing up. Put this tower in a hot desert area, where the daytime surface temperature sits at around 40 degrees Celsius (104 F), and add in the greenhouse effect and you've got a temperature under your collector somewhere around 80-90 degrees (176-194 F). Scale your collector greenhouse out to a several hundred-meter radius around the tower, and you're generating a substantial volume of hot air.

Then, raise that tower up so that it's hundreds of meters in the air - because for every hundred metres you go up from the surface, the ambient temperature drops by about 1 degree. The greater the temperature differential, the harder the tower sucks up that hot air at the bottom - and the more energy you can generate through the turbines. - source

Great comments too.

The part that caught my attention is the 80 year life span of the plant - it's essentially disposable. Is this the final outcome? Quick cycling disposable super-cultures? Yeah, well, isn't that where we've been headed for 10,000 years?

Related:

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voguy · Post by **voguy** » 07-27-2011 02:59 PM

BTW, Squid, not to derail the thread, but on the Coast web site there was a link to a DIY Solar energy site that is selling a $149.00 video on how to make your own solar panels.

I followed the the (rather boring) video, and then did some searching. I found two things that were interesting in the DIY area.

1 - Most people are challenged by making a frame to hold solar panels, or know the basics of construction, protection, and electricity.

2 - You can buy bulk solar cells, which when soldered in a certain configuration can make a solar panel. The panel needs to be between 14 and 18 volts. The bulk panels come in "bricks" which are shipped from places like Asia with 20-50 cells held together by wax.

So the process is to get them out of the wax, make a frame, mount them, wire them up, and then build a charger.

I'm sort of wondering how this might work. BTW, I have yet to try out that Lister engine we talked about elsewhere, but since the restaurants around here had a 5.25% increase in the cost of disposing french fry oil, I wonder if that could be used for a fuel source?

SquidInk · Post by **SquidInk** » 07-27-2011 10:47 PM

Wait... solar panels, veggie oils, and listers?? Man! You're speaking my lingo - but I'm not sure I understand...

I've seen plenty of DIY solar before. Believe it or not, I'm not sold on solar. I like this design however, due to it's use of temperature differentials. The electricity they generate should be used to spin up enormous flywheel energy storage modules, which can then deliver when needed.

YEAH! '43 Lister -- still the best.

Dale O Sea · Post by **Dale O Sea** » 07-28-2011 05:47 AM

I wonder if this scales? We have a lot of desert area where this will work great. so putting up 1000 or 10,000 of these things seems like a no-brainer to me for some forward thinking energy investors..

But will pumping that much hot air up to 2000+ feet, mixing it with all that cold air that is up there cause problems?

I can't say..not smart enough, heh. My brain keeps going where it went during the debate over if the space elevator will suck the atmosphere off of the planet..

voguy · Post by **voguy** » 07-28-2011 07:33 AM

To answer Dale's question first, solar could be scale-able. The trick with solar is maximizing exposure which requires panels to be out in the open for the maximizing the pickup of energy. You can also hedge your odds by employing some refractive technology. The university around here has powder coated 28" x 14" skirts in reflective silver to reflect some of the off angle incoming rays to parts of the solar cell. They are also experimenting with a way to turn the panels toward the sun. But of course to do that you have to have power for motors to turn the panels, so it's not that easy. And solar is not really a solid answer for days when you have overcast skies. It only works real well when you have large marine grade batteries and lots of alternative power demands, (ie: LED lighting, and appliances requiring little draw).

The lister is interesting because it's simple to run and in an urban setting you can find fuel anywhere. Connect that puppy up to a small genset and you have a pretty nice engine. Around here we have 4 fast food joints, all paying to have their fry oil disposed. Imagine if you could tap into that, saving them the cost of recycling, and you get free fuel.

There is also wind generation which has it's own limitations, but I wonder if you were to have a combination of all three, how that might play for someone wanting to go off grid.

BTW, Squid, there is a guy around here that does all the county fairs, and uses a listor to drive his ice cream maker and refrigerator at the fair. We had a long talk the one day, and you're right, the things are pretty damn simple.

One of the links, (if you can stand the ads on the right), is a DIY site on making you own
Solar Panels. It shows you how the bulk cells come from China incased in wax, and you have to cook them apart, clean them, solder them all together, and ten put them in a frame. Alternatively, this page has some good tips.

This page has some good tips on wind generation and chargers.

SquidInk · Post by **SquidInk** » 07-28-2011 10:13 PM

Great links, VO. It's getting really inexpensive to build those panels.

I'm glad you got to scope out a Lister up close.

Sinner · Post by **Sinner** » 07-28-2011 10:42 PM

Oh great now you guys have me reading about the Lister engine on the "Lister engine forum" further fueling my off the grid fantasy.

SquidInk · Post by **SquidInk** » 07-28-2011 10:57 PM

voguy · Post by **voguy** » 07-28-2011 11:10 PM

I don't think it to be such a fantasy.

There are two big issues to live off the grid. The first being you have to change your energy consumption. Gone are the days of getting up at night, turning on the bathroom light and then going back to bed leaving it on. Gone are leaving the computer run 24/7, or the A/C in the house on while you take off for a week on vacation. You look for ways to limit consumption, rather than mindlessly ignoring what you consume.

The second thing is that you have to know your technology. It's like the old days when cars were repairable. If the water pump goes out, you go to the part store and buy a pump, change it, and on with life. Listor, solar, wind, all require a minimum investment in knowing the technology, how to work with it, and how to repair what goes bad. If you can KISS and know how to work with it, you got it licked.

The payback can be massive, (depending on your income level). I calculated that I could pay off my investment in less than 3.7 years, and after 5 years selling watts back to the grid. Typically you're talking about $175 to $235 a month savings from paying a power company.

BTW, one other thing we didn't take into consideration is geo-thermal, solar water heating, and what you can do to your residence to keep losses at a minimum. The example being, if you improve your home to raise the R factor of walls and windows, you can cut heating and cooling bills. There are some guys in Canada who have been experimenting around, and the one fellow has a 1,990 square foot home, and during winter he heats it typically with two, or three logs in a basement wood heater.

Sinner · Post by **Sinner** » 07-28-2011 11:18 PM

I hear ya! It is a fantasy for me now though. I am not selling my home until my children have moved on with their lives.
After that though nothing will stop me from fulfilling many fantasies, well except my wife, but I will have her under control by then hehe.

voguy · Post by **voguy** » 07-28-2011 11:21 PM

My wife is all for it. She hates writing the check to the power company as much as I do. She also looks at it as, "the more we don't pay to them, the more we keep for ourselves."

I think the technology is there, the implementation is practical, and it's at a point that with minor lifestyle changes it's completely possible.

Sinner · Post by **Sinner** » 07-28-2011 11:37 PM

Your not really "off the grid" though if you are selling power back to the power company, at least not the way I define it.

I am talking not have any service of any kind run to my house. That to me is off the grid.

voguy · Post by **voguy** » 07-29-2011 06:52 AM

Well, that's true. I look at it as; if I'm making 12 kw and hour, and consuming 3 kw an hour, and I don't have the ability to store more, then might as well sell it to the people who have been charging me all this time and recoup the investment.

Dude111 · Post by **Dude111** » 07-29-2011 06:57 AM

It all seems a bit interesting!

Sinner · Post by **Sinner** » 07-29-2011 07:13 AM

voguy wrote: Well, that's true. I look at it as; if I'm making 12 kw and hour, and consuming 3 kw an hour, and I don't have the ability to store more, then might as well sell it to the people who have been charging me all this time and recoup the investment.

Oh yea I understand that, but my dream is to build an efficient home and garage on a few acres without any service. It costs money to have service run out to a house, sometimes a substantial amount depending how far in the boonies one may find himself. This savings would offset some of the cost for hardware etc.

Chances are I would happily use up most of my electricity anyway.
I would use generator/solar panels/battery packs for electric. I would use wood pellets to heat the house and use wood stove/boiler for radiant heat in the garage. or a combination there of. Also a propane tank and furnace for back up.

The only bills I would find acceptable are maintenance/ satellite TV/ property taxes. Oh and I would have a 500 gallon diesel tank for my generator and have non road tax red diesel delivered on a keep fill.

Being that our electricity is fairly cheap where I live, I probably wont save a dime.....but I would be "off the grid".