Slashdot Mirror

Works at night. (Ground heat release.) Low maintenance, few moving parts, durable, doesn't require uncommon, imported elements or the same kind of energy inputted into its construction, doesn't make the ground under it useless. Politically this is easier to sell than relying on China for the arrays. Scaling photovolatics to the level needed to get to an all-day average of 200MW requires a lot more ongoing maintenance. This is easier for voters to understand, and looks 'cool' from the highway. :-)

Let's see, works at night with ground heat release...perhaps, but I am doubtful, their own drawing indicates a thermal gradient within the "chamber" caused by the "greenhouse effect," so any benefit of the ground thermal storage would seem to be quite low given the low rate of radiation as the required airflow cools the top layer and the thermal resistance of dirt is very high.

Low maintenance...perhaps, we'll let that slide for now.

Few moving parts...vs. photovoltaic? I think not since you can't go below zero in counts of physical items.

Durable...hmm, perhaps the materials are durable but I have no idea...they don't tell me what they are! I do know that the building I work in is all of 4 years old and has all kinds of leaks and problems...and it is tiny by comparison. This would be the largest area building ever built, by no small margin! The Dubai airport currently checks in as the biggest at not even 6% of this beast! So much for your low maintenance as well me thinks.

Doesn't require uncommon, imported elements or the same kind of energy inputted into its construction...how exactly are you going to move the materials to construct this monstrous structure there, let alone the over 2000 feet into the air? As for materials for construction, we have been producing solar cell materials for decades, it is essentially a commodity now and we don't have any idea what material they are going to build their tower out of do we?

Doesn't make the ground under it useless...this one made me laugh the most. How exactly is a 4 square mile greenhouse with untold winds at the core going to be used? Remember, the idea here is to raise the internal temperature significantly, so what are you going to do in there? Remember also that you can only access the land from the perimeter, and you can't put a lot of walls in there, they would disrupt the airflow. How is this useful land again vs. raised panel arrays that you could build any building you wanted underneath?

Politically this is easier to sell than relying on China for the arrays...okay, perhaps, and until a few days ago I could have said, oh really, but sadly they have announced that they had to turn to China for production as well.

Scaling photovolatics to the level needed to get to an all-day average of 200MW requires a lot more ongoing maintenance...huh? Why does maintenance go up with scale here? Add more panels to have peak production way past the current level of nearly 7x the production then! I already firmly believe their design will have a pittance the daytime production at night, so they won't be this magic, constant output station, just as panels aren't, you still need energy storage (again, I am not buying into the ground thermal storage) and you still don't have ANY moving parts!

This is easier for voters to understand, and looks 'cool' from the highway...I think you mean easier to fool voters into paying for, but yes, the coolness factor would certainly be there.

So of your ten points...I believe you only have two left standing, and both of those are pretty darn weak.

First Solar has a 25 year warranty on the power output of their panels. As far as I've seen this is pretty common for panels intended for large installations.

Here's a couple random links to back that up:
https://energy.wesrch.com/User_images/Pdf/L02_1221963706.pdf
http://www.evergreensolar.com/upload/pdf/us/Warranty_Cedar_Spruce_v1.5-060329_US.pdf

Wait, you're suggesting by "I dont know of any company that could afford to beat out the fossil fuel companies to do so." that there aren't companies in the US trying to make money off alternative energy? Further, lots of state governments are actively trying to promote alternative energy, which undermines the theory that the government is afraid of a tax revenue collapse. State governments are subsidizing alternative energy using those very tax revenues, in the hopes that home-grown alternative energy producers will create even more tax revenue in the future.

I hate to sound like a slashvertisement, but I think the following US companies and groups would all disagree with you:

Evergreen Solar (producer based in Mass.)
Heliodyne (producer based in California)
Google (installing panels on its roof)
Solar Energy Industry Association (US trade group)
Tesla Motors) (selling 100% electric cars in the US)
List of solar manufacturers in the US
US solar power installations increase 33% year-to-year

The New York Times has a story about this issue: "Venture Capital Rushes into Alternate Energy" suggesting that $1.5 billion in VC money was invested in 2006 alone in new companies who hope to profit from overthrowing the energy status quo. If you add private equity money then there was $18.1 billion in dealflow in 2006 in the alternate energy sector. Or listen to a 2004 story about the same issue.

It's nice to think that there's some great conspiracy against alternate energy, but the simple truth is that there is a lot of market action in the field and nothing stopping people from making money in it. There is a HUGE amount of money to be made from alternate energy and plenty of people are trying to make it.

Truly. Energy efficiency in solar cell production is a good thing. There are some companies which are attempting to be more efficient.

Their production method is not wafer based. Much more efficient in both energy and material, in spite of the fact that they grow the ribbons in mid-air ! Be sure and watch the video on their site, it's fun.

Astropower went bankrupt in February and was bought by GE's PV division in March.

Recycling bum wafers may be a great way to get more value out of the chip making process. But as a standalone business, buying wafers, turning them into solar cells, and turning the cells into panels, it probably doesn't compete well with Evergreen Solar's string ribbon fabrication process.

It might work better if the chip companies did the recycling themselves, and also built panels themselves and/or put standardized cells on the market and let the price find its equilibrium.

Some downsides to this sort of recycling:

The market price of a wafer as a solar cell is a drop in the bucket compared to even one or two of the chips on it (let alone maybe half) being good enough to cut out and sell - and deliberately building extras for the cell trade would drastically increase the cost of the cells. That means any money to be made by selling solar cells will not be factor driving their production quantity (beyond trying to convert all the bad wafers).

The supply of such recycled-as-solar-cell wafers will thus be completely driven by the market forces on the company's underlying chip business and the yeild percentage of its processes - with the incentive always being to fix the process to improve the yeild of chips - which cuts into the yeild of cells.

This makes it hard to build an independent business based on building a fab to recycle bum wafers from the chip companies into cells as a necessary step in making panels. The supply of raw wafers is too iffy, and using it to make more cells from fresh wafers to meet production targets makes the cost-of-goods fluctuate too much.

A better model might be for the chip manufacturers themselves to add fab steps to recycle their bum chips into cells themselves, and sell them on the open market to panel assemblers. Ideally some of the steps could be done with the same equipment as the chip fabrication (without risking contaminating it and lowering chip yeilds), minimizing the capital cost. Bum wafers could be stockpiled and processed when market fluctuations created gaps in the fab's schedule, or on older equipment or in older fabs that otherwise would be retired or taken out of production for refurbishment. Multi-company standards for the characteristics of the recycled-wafer cells would let a panel manufacturer use cells from multiple fabs, smoothing out market swings between products of different chip manufacturers.

In this scenario a panel manufacturer could invest in only assembly equipment. He could make a recycled-wafer model when the supply of such cells was adequate, and use new-material cells built by a different process (such as string-ribbon) with a less-pricey start point, to make another model when the supply of recycled wafers was inadequate for the demand for panels.

...do the same studies as does Odum, I'd be interested. But by a cursory glance at his website, he does sound like he's interested in a fairly narrow bit of the energy production spectrum

His 'worse case' scenarios are always current technology - and even his base cases are a *lot* more optimistic than his worse case scenarios.

Alsema (Professor in the Dept. of science technology and society at Utrecht University, Naterlands) has 13 peer reviewed papers published on PV all relating in some way to EROEI or environmental impact. In his most recent publication (2004) in Refocus he says:
"Recent studies give the impression of photovoltaics having considerable environmental impact. Looking closer at the data however, it is clear that these studies are based on photovoltaic systems of the late eighties, with only minor recalculations. Since the photovoltaic market has increased rapidly, a lot of progress has been made regarding the environmental profile of photovoltaics." He goes on to show, for example how current production ribbon silicon panels have a payback period of 1.2 years (and that is silicon, not even thin flims like CIS).

I favor Odum's numbers (from 'Environmental Accounting'), which include...

If you don't like Alsema cause he blows your outdated arguement read Kato. Kato (prof. Japan agriculture university) has 25 publication all dealing with photovoltaics. He has several publications dealing with EROEI.

Or read this (note this is dated and the 2 and 1 modules are already on the market).

Not all Solar is as toxic as you make it out to be. Significant strides are being made to manufacture panels as cleanly as possible.

Evergreen Solar is one company with a cleaner manufacturing process.

First Solar uses a thin film technology that is more easily recycled than traditional panels. Their manufacaturing plant includes recycling technology. It is a serious concern of their engineers.

Astropower used to manufacture their product from recycled silicon from the semiconductor industry. It isn't clear they still do so since being sold to GE, but they represent another attempt to reduce the environmental impact of the panel manufacture.

Lastly, the US Department of Energy remains optimistic that by the time the contemporary solar modules have reached end of life, recycling technology will have vastly improved in efficiency. Certainly we'll have a better chance of recycling solar modules than we will of spent uranium.