DescentBB

remember that 1000meter tall solar energy tower they are building in outback australia?
http://www.enviromission.com.au/

well it seems they are looking to build one or more of them in Arizona USA as well. i just read this PDF on the website:

(released June 21 2005)

TOP SITES IDENTIFIED FOR US SOLAR TOWER BID

US Solar Tower developer, SolarMission Technologies, Inc, has identified three potential sites in Arizona that provide ideal conditions for Solar Tower power stations, as the bid for US development enters pre-feasibility.

All sites are located within the highest solar insolation region of the United States â?? solar
insolation being the amount of solar radiation incident on the surface of the earth; a vital factor
to successful Solar Tower operation.

Sites with high solar insolation, flat stable geology, access to electricity infrastructure and
strong political support for renewable energy development are essential to site selection for
Solar Tower development.

The Solar Tower concept uses solar radiation to create a constant thermal updraft of heated air
to drive turbines to generate clean sustainable electricity.

Early discussions with regulators in Arizona have indicated strong support for Solar Tower development in the area.

The centrality of the Arizona sites and the particular location of each site, would enable electricity to be dispatched to meet the burgeoning demand of the South West, positioning Arizona as a potential exporter of renewable energy in the region.

An optimization study is planned to evaluate the distinct and unique benefits of each site
including a full and measurable assessment of the economic viability of Solar Tower development in the region.

Development in the US is poised to take advantage of recent Australian Solar Tower improvements to scalability and profitability that will impact on market and site selection.

US development will be a rollout of the re-engineered concept developed in Australia by EnviroMission to take full advantage of the inroads made with output, scale, and capital cost.

At this stage of site appraisal, all three sites offer benefits that will not discount a decision to
secure any or all of the sites, paving the way for significant development at a time when energy
policy is dictating a preference for reliable grid connected clean green power.


Ian Riley
N Company Secretary
Chief Financial Officer
EnvironMission LTD

Sounds good to me. Cheap, completley clean energy is always a plus.

not bad, looks interesting

There where some posts around here in other threads about how solar panels consumed more enegery during their production then they ever create when in service. Was that ever proven or debunked?

Mr. Perfect wrote:There where some posts around here in other threads about how solar panels consumed more enegery during their production then they ever create when in service. Was that ever proven or debunked?

it doesn't matter, these things don't use solar panels, they run on the power of the sun heating air.

they basically just errect a HUGE hollow tower, with turbines in it. that's it. it's like a manmade volcano.

check out the website, it's a pretty amazing tech - extremely simple but works surprisingly well.

Heh, I am smelling fried chicken ... just imagine a bird getting sucked into such a thing ...

We have some huge "wind parks" at the North Sea, and I have seen a cartoon recently of a sliced sea gull on the ground with a friend at its side yelling "I told ya: Don't take the short cut through the wind park!"

Mr. Perfect wrote:There where some posts around here in other threads about how solar panels consumed more enegery during their production then they ever create when in service. Was that ever proven or debunked?

I would imagine since the manufacturer has to pay for the energy to make the solar panel, and in so doing passes those costs on to the end-user, I'd say no. However the fact that the cells can last for 20 years +, I'd also say no. I guess if in the 20+ years in operation, it was never sunny, then yeah.

i may have once mentioned that here Mr Perfect, but it would have been ages ago. i often heard ppl saying it in a science newsgroup i havn't frequented for probabaly over 2 years. i was unable and unwilling to bother substantiating the claim. so treat it as rumour until substantiated.

supersheep if it were true then it would not make solar panels useless. it would merely logically delegate them as energy storing devices (batterys) instead of energy harvesting devices.

how much would you pay for a battery that only works during the day, but otherwise never runs out of power?

it may be a strange way to think about it. but when you just think of the input and output figures it makes sense.

both batterys & power sources:
- take a certain amount of energy to create.
- output energy over time.

you could think of all power sources as really just batterys with extra features (like perhaps never draining).*


this is all of course irrelevant when talking about the solar tower tech. it creates more energy than was used to create it.


* actually if you wanted to get serious, you can think of the entire universe as a battery that we just drain energy from. laws of thermodynamics and all that. all energy can be traced to UNrenewable sources. fossil fuels are essentially batterys for solar energy. even the sun will die one day.

Roid, I work as a tech in the battery industry and I'd have to disagree.
Photovoltaic energy cells are highly inefficient and would not be my first choice for energy creation or storage. In fact, the only real benefit in solar cells is their energy conversion.
If it took more energy to create a solar panel than it produced, then it would be a tremendous waste to manufacturer them for converting energy to distribute. Why do all that, when you could just distribute the energy you used to create the solar panel initially?
The only real case where your argument would apply IMHO, is in cases such as Solar Powered calculators, outdoor lighting, etc. That is, as convenience and to save us from the mass quantity of dry storage batteries that would be used and thrown out.

Solar and hydrogen based energy will take us farther then most believe....

<still hoping for a Dyson Sphere>

Flatlander wrote:<still hoping for a Dyson Sphere>

Star Trek Dork!

Richard Cranium wrote:

Flatlander wrote:<still hoping for a Dyson Sphere>

Star Trek Dork!

I knew what a Dyson Sphere was before I ever saw that ST:TNG ep

SuperSheep wrote:Roid, I work as a tech in the battery industry and I'd have to disagree.
Photovoltaic energy cells are highly inefficient and would not be my first choice for energy creation or storage. In fact, the only real benefit in solar cells is their energy conversion.

what about their size? they are way smaller than the total battery size/weight needed to supply the same amount of energy.

PV cells wouldn't have been my first choice either, the first thing anyone thinks is "oh batterys" and i was no exception. however i now try to think outside the square

creating (and charging) batterys, or creating solar PV cells: either way it's an investment of energy with the ability to get that energy back out again.
it's all just inputs and outputs, and that can be used to test the efficiency.

do you see?

i'd say that anything with more efficiency than 1:1 is a power source. anything with less is considered a battery. definitions solely based on figures.

this is how i think of it. but you must have a different idea on what is and isn't a battery, and why. i'd love to hear them, please. you are in the industry so you have probabaly thought about this more than i have.

If it took more energy to create a solar panel than it produced, then it would be a tremendous waste to manufacturer them for converting energy to distribute. Why do all that, when you could just distribute the energy you used to create the solar panel initially?

distribute that energy via batterys?
yes it's a logical idea if they are more efficient.
you'd have to factor in the amount of energy required to manufacture a battery as well as charge it.
and compare that to the amount of energy the battery will yeild.

this may or may not be more efficient than manufacture of solar panels. remember a solar panel will continue to yeild energy until it breaks, so that's a LOT of energy compared to one battery charge.

The only real case where your argument would apply IMHO, is in cases such as Solar Powered calculators, outdoor lighting, etc. That is, as convenience and to save us from the mass quantity of dry storage batteries that would be used and thrown out.

iirc cheap basic Solar PhotoVoltaic (PV) panels get an average of around 10% efficiency. good for a substitute for dry storage but not really worth considering for realistic power production. this kindof bad efficiency would likely be what the original poster had in mind when he was saying that "solar panels during their lifetime don't cumulatively produce as much energy as used in their initial creation"

However solar PV panels these days are getting above %30 efficiency. also they are cheaper to manufacture. cheaper to manufacture energywise as well - probabaly mostly due to substituting large PV cells for small PV cells - with a lense concentrating the light onto the small PV.

a lot of solar power isn't even PV anyway. it's Thermoelectic (TE) - using the sun to HEAT something which then runs steam through a turbine. i wish i could give some efficiency figures for TE, but i spent a while yesterday looking and came up with nothing.

the solar tower in this thread for instance, would probabaly be designated "ThermoElectic". it uses solar energy to heat air, which then runs through turbines. it even uses vats of water as "heat batterys" so that it can produce power both night and day.


since you work in the battery industry, can you tell me some round-about figures for various battery efficiencies? there must be thousands of batterys so just choose somethings relevant.

AFAIK - the old style Gallenium Arsenide solar cells were incapable of returning the energy required to manufacture them - within their usable lifespan. This because the manufacturing techniques were very poor, cost was very high, and the efficiency of them was abysmal.

I know for a fact the system we installed at our tree farm would keep a bank of 12 batteries charged without issue, but the cost of the panels was astronomical, and the ONLY justification for using them was that power was unavailable!

When they shat themselves about 4 years later - we installed a windmill to generate power. Well, it was a lot cheaper, and rated up to 160km/h wind speed - but three separate times it blew away. Twice we found the blade - but the third time it was probably blown clear off the property - or so high up one of the pines it was simply lost.

Shortly thereafter we had mains power put back on the property because my Mother put her foot down about the coal range - having to remove 3 buckets of soot from the thing every 3 days of use!

I know solar cells are far more efficient than they used to be, and they're in major production now (Germany has several projects using them) which will drop the cost significantly - so I guess the engineers have done their work, and the sums add up.

I find it highly unlikely energy-negative strategies are being deployed.

Mobius wrote:energy-negative

i wish i thought of using that expression earlier. could have saved me some explaining time.

also looky
http://en.wikipedia.org/wiki/Solar_cell ... gy_payback

Solar cells and energy payback

There is a common but mistaken notion that solar cells never produce more energy than it takes to make them. While the expected working lifetime is on the order of 40 years, the energy payback time of a solar panel is anywhere on the order of 2 to 30 years depending on the type and where it is used, see Net energy gain.

which prettymuch puts that to rest

Batteries store energy in some way. Either through chemical processes as in most of your standard battery types, potential energy as in flywheels, magnetic as in superconductors, and even electrically as in capacitors. I'd classify any device that stores energy in some fashion as a battery.
Generators are those devices which rely on an external source for their delivery of energy. Solar cells, hydroelectric power plants, thermoelectric power, etc.,. These devices will not deliver power if the external source is removed.

distribute that energy via batterys?

Please don't read into my comments. I work in the battery industry, I'm not a slave to it. Here's what I meant...
Say you have Company A building solar panels using Plant B's power. Plant B must deliver energy to company A which otherwise they wouldn't. Now say Company A goes out of business, and at the same time Customers A,B, and C switch their power to Plant B. Now let's also say, they just so happen to use the amount of power that Company A was using. Well, that is more efficent(if solar cells used more energy in production than during their life) than if Company A turned around and bought Plant B, retrofitted them with their solar panels, and provided Customers A,B and C with the power.

However solar PV panels these days are getting above %30 efficiency. also they are cheaper to manufacture. cheaper to manufacture energywise as well - probabaly mostly due to substituting large PV cells for small PV cells - with a lense concentrating the light onto the small PV.

Solar panels at the high end are getting 30% eff. Most commercially available panels are still in the 10-20% range.

since you work in the battery industry, can you tell me some round-about figures for various battery efficiencies? there must be thousands of batterys so just choose somethings relevant.

30-50W/Kg for standard lead acid and NiCd.
80-100W/Kg for NiMH
>100W/Kg for Lithium based
Now although solar panels can achieve near 200W/Kg, keep in mind that is only in direct sunlight. Also, they produce ~300W/square meter which is quite large compared to a battery. So, while they are great for huge solar array power stations, or slapping them on your roof, they are not the be all, end all power source.

oh. no i didn't mean WEIGHT efficiency (although that's important too i guess, so thx). i ment efficiency as in the measure of how much energy is NOT wasted.
as in: how much energy is used to charge the battery, divided by how much energy the battery can then discharge.

the energy difference between charging and discharging, as a ratio or percentage. the efficiency record for solar panels is currently a little over 30%, but outside the cutting edge the majority of current solar panels seem to be around 10%-14%.
if you put 100 Watts into one battery and then got 30 Watts out, that would be %30 efficiency.

do you know figures for things like that?

(i imagine calculating how much energy is used in the manufacture of the battery would be too difficult to bother with atm. although with single use batterys it's probabaly a very important figure to factor in - because it would be the closest way to compare efficiency relative to a solar panels.)

i think i'm gonna start a new thread on this. i fergot this thread sposed to be about the solar tower

Last post then in this topic about batteries. In answer to your question of efficiency is not straight forward. There are many factors on how efficient a battery is, and this paper just so happens to talk about battery efficiency and its impact on PV systems.

http://www.sandia.gov/pv/docs/PDF/batpapsteve.pdf