CNN has a good story updating the status of the Australian 50 MW solar tower (I prefer the name 'Solar Chimney') planned by EnviroMission (OTC: EVOMY.PK, ASX: EVM.AX). Quite a few changes have been made since my original post, the biggest being that the tower was downsized from 200 MW to 50 MW. In addition incorporation of two enhancing technologies has allowed smaller units to become economically viable and eligible for government funding.
The re-engineered tower will be a 260 foot-diameter, 1,600-foot tall structure, taller than the Sears Tower, surrounded by a two-mile-diameter glazed solar collector at ground level. About 8 feet tall at the perimeter, the solar collector will gradually slope up to a height of 50 to 60 feet at the tower's base. Acting as a giant greenhouse, the solar collector will heat the air to about 68 oF (38oC) hotter than the outside air entering at the periphery, using the radiation from the sun. Acting like a chimney, the air is sucked into the tower, where it passes through a multitude of wind turbine generators clustered around the structure. The tower will cost an estimated $250 million to build, with construction expected to start in 2007 pending receiving a $75 million grant from the Australian government.
The two enhancements are:
- The efficiency of the collector zone, which is substantially increased by replacing a portion of the collector with a vastly improved system. The air heaters are different from other direct gain mechanisms as solar energy is captured by two mediums: a glass plate and a metal plate. This configuration greatly reduces heat loss through reflectance, radiation and convection resulting in greater efficiency and durability.
- More energy will be collected and stored via a heat storage facility which will provide base load capability for energy generation, in-turn providing the Solar Tower the ability to meet both shoulder and peak demand. Power can be generated by the facility 24 hours, 365 days per year, if required. Saltwater ponds sit outside the solar collector and trap heat in layers of saltwater during the day. At night the heat is released to power the tower's turbines. Solar radiation is captured in the ponds and stored in the bottom level of the ponds where the heated liquid can be continuously extracted at 35oC to 50oC above ambient temperature. Heat can be delivered to the collector zone, the region beneath the collector, via a heat exchanger which in turn further heats the air within the collector zone providing a greater differential in temperature and enhancing the ability to maintain air velocity sufficient to generate high load factor power day and night, throughout the year .
The enhancements allow units to be constructed with a smaller footprint, regardless of their nameplate capacity, and operate with a much greater efficiency or capacity factor. In essence the new technology developments, created by EnviroMission and protected as intellectual property, allow the Company to get ‘more from less’ out of the Solar Tower.
An analysis by Waterville Investment Research in New York concluded that a 50-megawatt solar tower would be competitive with other renewable-energy sources, while a larger version could produce electricity for the same cost as conventional power plants, and possibly less.
The 50-megawatt Tapio Station plant is just the small model: A half-mile-tall version is in the works for China, and EnviroMission is scouting sites in the American Southwest for other possible sky-scraping power plants.
The enhancing technologies and the Australian government's creation of the Low Emission Technology Development Fund (LETDF) led EnviroMission last year to downsize the solar tower plant to 50 megawatts. EnviroMission bought 24,000 acres of Tapio Station, the wheat and sheep farm located near the southwest New South Wales town of Buronga. State Significant Development status has also been granted to the project by the NSW State Government recognizing the significance of the project to NSW and has passed the planning approval process to the NSW Minister for Planning ensuring a streamlined approach to the planning process.
After four years and 17 capital raising's, Enviromission is trying to grab an $75 million piece of $370 million allocated to low-emission energy projects to keep its dream alive, a decision is imminent. It successfully met the terms for applicants to the LETDF. Successful applicants of the LETDF will be eligible for 2:1 dollar funding of project capital cost to demonstrate low emission technology using new intellectual property with the potential to deliver commercial large-scale energy generation and emission abatement set out in the program's 2030 targets. EnviroMission lodged its application in line with the 31 March, 2006 LETDF application deadline and joins a list of 30 potential applicants awaiting the formal assessment process ahead of an announcement early in the new financial year.
The initial design was a massive structure and too big a risk for investors. The station was to be a 200-megawatt monster with a 3,300-foot-high tower surrounded by a 4.5-mile-wide solar collector. The tower would have been nearly twice as tall as the tallest structure on earth, the CN Tower in Toronto. "People thought I was stark raving mad," said Roger Davey, chief executive officer of EnviroMission. "They said you couldn't do it, that it would never be commercial because it was so big and such a construction nightmare." Not to mention the estimated $800 million to $1 billion price tag.
This is one of the most interesting technologies I have seen, if only they could build one, they have been trying to get financing for years. Continuous power from a solar source without complex energy storage. Capital cost of $5000/kW is very expensive, about twice that of a nuclear plant, but with much lower O&M costs and no fuel costs. This comes out to $0.09-$010/Kw without any susidies, which is may be lower than any other renewable energy plant. Wind? They claim they want to compete with coal.
Resources:
Tower of Power,Todd Woody, CNNMoney.com, July 20, 2006
EnvroMission Limited, South Melbourne, Victoria Australia
I wonder whether they will get the money. The Australian government is so conservative and pro coal that it wouldn't surprise me at all for them to pull the plug just to ruin something promising (perhaps I am too cynical). I believe one of the reasons not mentioned here as to why Enviromission have delayed so long is that the Federal Governments Energy White paper was very dissapointing as far as renewables go compared to coal or natural gas.
Posted by: marcus | August 03, 2006 at 12:36 AM
Here are some relevant figures for the capital costs of various energy options -- these figures are from a presentation done by Dr. Per Peterson of UC Berkeley on "material inputs". How does this "solar chimney" compare?
Nuclear: 1970’s vintage PWR, 90% capacity factor, 60 year life [1]
– 40 MT steel / MW(average)
– 190 m3 concrete / MW(average)
Wind: 1990’s vintage, 6.4 m/s average wind speed, 25% capacity factor, 15 year life [2]
– 460 MT steel / MW (average)
– 870 m3 concrete / MW(average)
Coal: 78% capacity factor, 30 year life [2]
– 98 MT steel / MW(average)
– 160 m3 concrete / MW(average)
Natural Gas Combined Cycle: 75% capacity factor, 30 year life [3]
– 3.3 MT steel / MW(average)
– 27 m3 concrete / MW(average)
Refs.
1. R.H. Bryan and I.T. Dudley, “Estimated Quantities of Materials Contained in a 1000-MW(e) PWR Power Plant,” Oak Ridge National Laboratory, TM-4515, June (1974)
2. S. Pacca and A. Horvath, Environ. Sci. Technol., 36, 3194-3200 (2002).
3. P.J. Meier, “Life-Cycle Assessment of Electricity Generation Systems and Applications for Climate Change Policy Analysis,” U. Wisconsin Report UWFDM-1181,
August, 2002.
Posted by: Kirk Sorensen | August 03, 2006 at 11:31 AM
I've been wondering why this idea has been getting traction, but the converse idea, a tower that generates a downdraft from evaporative cooling, has apparently not. The cooling tower has the advantage of not requiring the large 'skirt', since it exploits the presence of natural hot dry air produced by sunlight hitting the general neighborhood.
Posted by: Paul Dietz | August 03, 2006 at 11:54 AM
Minor typo -- that should be the "CN Tower in Toronto", not the "CNN Tower in Toronto"!
Posted by: Michael Lawson | August 03, 2006 at 11:56 AM
I frequently see this error regarding temperature and temperature rise.
Whilst a temperature of 38 oC is equivalent to 100 oF... a rise of 38oC is only a rise of 38 x 1.6 = 60.8 oF
Posted by: glynne jones | August 03, 2006 at 01:25 PM
I hope they do build it. My thought would have been a smaller (100m) dia. dishes w/ a more highly reflective surface. A collector could then redirect the energy toward a high quality heat storage unit.
Posted by: petropest | August 03, 2006 at 01:30 PM
Apologies for typo.. my brain was stuck in miles/km?? It should read:
I frequently see this error regarding temperature and temperature rise.
Whilst a temperature of 38 oC is equivalent to 100 oF... a rise of 38oC is only a rise of 38 x 1.8 = 68.4 oF
So which is the correct temp rise for this project... the oF one or the oC?
Posted by: glynnej | August 03, 2006 at 01:31 PM
PD, I have also wondered about the cooling tower concept. I haven't heard much about it in recent years. Please share whatever you have heard lately.
Posted by: Bde2200 | August 03, 2006 at 01:42 PM
Please share whatever you have heard lately.
Essentially nothing, which is why I was wondering.
Posted by: Paul Dietz | August 03, 2006 at 03:03 PM
Both mistakes were mine and have been corrected in the text. The temperature rise is 68 F and it is the CN tower.
BTW I use the Shaw-Stone & Webster report found here for all my reference data on costs of generating power. This is the latest comprehensive report I have come across. It may be biased towards nuclear, but all forms of energy seem to get some sort of subsidies and everyone has an agenda.
Posted by: Jim from The Energy Blog | August 03, 2006 at 05:11 PM
This is a very interesting reappearance of the saltwater ponds concept. I was aware that they were developed in Israel some time ago, but I'd heard nothing recently. Using them as ultra-cheap thermal storage for this tower is damned clever, and I'm glad the principals made the connection.
(For the uninitiated, the ponds use a black bottom to collect solar radiation and heat beneath several feet of water, and a stratified concentration of salt to keep the heat from rising due to convection.)
Posted by: Engineer-Poet | August 03, 2006 at 11:47 PM
PD, they are still talking about it:
http://www.israel21c.org/bin/en.jsp?enPage=BlankPage&enDisplay=view&enDispWhat=object&enDispWho=Articles%5El505&enZone=Technology&enVersion=0&
Jim, sorry for the OT discussion, but consider doing something on this concept.
Posted by: Bde2200 | August 04, 2006 at 02:36 PM
More:
4.5 cents\kilowatt in Australia, with construction costs amortized over 30 years assuming 10% interest in optimum locations. Even better numbers in Baja California
http://www.ecmwf.int/about/special_projects/czisch_enrgy-towers-global-potential/report_2005_extended.pdf
Look here under Sharav Sluices:
http://www.technion.ac.il/technion/agr/research/research.html
Northern Mexico:
http://construction.ecnext.com/coms2/gi_0249-88051/Consortium-plans-study-of-energy.html
Lots of info:
http://wire0.ises.org/wire/doclibs/SWC1999.nsf/id/A073ADCC0808F2D1C1256920003D6202/$File/224.pdf
Posted by: Bde2200 | August 04, 2006 at 03:27 PM
Seems to have a huge footprint, but if anyone has uninhabited room for something like this it's australia
Posted by: Andrew | August 06, 2006 at 06:01 PM
Unless they've changed their plans, most of the land underneath it won't be going to waste, it will be farmed, so you don't need vast areas of uninhabited land to build them. In fact they could be built close to population centers and the area underneath them used for market gardening.
Posted by: Ronald Brak | August 07, 2006 at 09:17 AM
I don't see these going up near population centers anytime soon. If people scream and whine about wind turbines destroying their view, the outcry will be ten times bigger over these solar towers.
Posted by: Jeff Olney | August 07, 2006 at 12:56 PM
Are you kidding? Imagine the view from one! If you could somehow keep the shadowing from impairing the operation of the tower, the sides could become prime real estate.
Posted by: Engineer-Poet | August 08, 2006 at 11:37 PM
I love this idea, and frankly I feel that visual pollution is just an excuse people that fear change use.
People travel to see windmills for goodness sake now suddenly white spinning towers are supposedly comparable to a coal burning smokestack dumping black greasy smoke into the sky.
The first time I read about this technology I was thinking that they should build it with an outer ring at the top coming down for cold downdraft production.
Hot Air up, Sprayers at the outer ring outside edge create a down draft that's a bit out. It seems like this would open up a bit of air space and reduce the pressure letting the air flow up easier. The hot dry air would help the down draft too.
I know it's hard to visualize and I'm not suggesting having the two sharing the same wall or turning the air 180 degrees to flow downward.
It seems like a cycle of hot air up and cold down would work to me with some difficult design involved.
Posted by: asdar | August 17, 2006 at 11:07 AM
30 years is an awful long time to amortise, but even so if 4.5c/KWh is real, that is a very good number for a technology which is only at the start of the experience curve. That should lead to a halving in long term costs, if the experience of wind energy is anything to go by.
The real problem with renewables seems to be not their costs, but the fact that they are intermittent - half the day (or more)the sun does not shine, and some of the time the wind does not blow - and Oz and Baja (and windy mountains) are a long way from most energy consumers. Long distance power lines are part of the answer, but they have heavy losses. There is a need for chemical energy storage which is carbon-free. Hydrogen is not the answer (too many problems) but ammonia may be, although the energy density is only 40% of oil. It is also a very good fuel for internal combustion engines and turbines. More on this at http://totalissues.blogspot.com/2006/08/ammonia-economy.html
and the subsequent post
Posted by: totalissues | August 22, 2006 at 05:36 PM
I wonder if it would be possible to dispense with the turbines in this scheme and instead generate power electrostatically. That is -- inject charge into the upward flowing air, and have the ions so formed be dragged 'uphill' against a strong electric field. I recall a similar scheme being proposed for use with natural wind, but the fixed geometry here could make the idea more practical.
Posted by: Paul Dietz | August 25, 2006 at 03:57 PM
Looks like I was right, they didn't get the money. Instead they've given money to a solar concentrator power plant and a brown coal pilot plant that captures and stores CO2. No surprizes regarding money for coal in Australia.
http://www.ausindustry.gov.au/content/content.cfm?ObjectID=ACCA1CF7-5900-4367-AA43BE6D0323ECD6&L2Parent=0786C9BE-08B7-4973-93429A645AEEC8E4&L3Parent=61B11DDD-1A32-42EE-9827BD5C63DE326D
Posted by: marcus | October 25, 2006 at 01:42 AM
I hope Enviromission has a backup plan (they should have knowing the Howard government).
Posted by: marcus | October 25, 2006 at 01:59 AM
Are there some nuclear concerns benifitting here, or is it more obvious ... everybody benifits from beating down the real hero, typical.
Posted by: young witha future | December 14, 2007 at 09:13 PM
I'm wondering, with Howard out, a the new prime minister handing over a ratified Kyoto protocol in Bali, will this project start moving again in Australia?
Posted by: Clee | December 15, 2007 at 04:15 AM
Here's a good backup plan: go to CA as well. More solar thermal competition in the Mojave would be a good thing, and the... political environment... for solar is probably much better in CA even with Howard gone in Australia.
Or Spain perhaps?
Posted by: Cyril R. | December 15, 2007 at 08:33 AM
Hi!
Best wishes for 2008
NOBODY has a better Solar Tower Update since august 2006?
In Spain, in ciudad real there was also a projet of solar chimney 750 m high, but no news since more than one year...
Please : a 2008 update is necessary!
Posted by: Ecolo127 | January 09, 2008 at 10:40 AM
Hi!
Best wishes for 2009
Has anybody a better Solar Tower Update since august 2006?
In Spain, in ciudad real there was also a projet of solar chimney 750 m high, but no news since more than two years...
http://www.ingenieriacampo3.com/
http://www.ingenieriacampo3.com/?ingenieriacampo3=51b673b6c8fff38afefe03ae3e7254fb&url=i%2Bd%2Bi+torre+solar+la+chimenea+de+fuente+el+fresno&corp=ingenieriacampo3&lang=es&mode=view
Please : a 2009 update is necessary!
Thanks
Regards
Ecologiste2
Posted by: Ecologiste2 | January 08, 2009 at 08:25 AM
There are news about giant "solar towers"
Two new websites are dedicated to them and they are very complete!!!
Please have a look on:
www.solar-tower.org.uk
and www.tour-solaire.fr
(and next month www.torre-solar.es)
Cheers
ecolo127
Posted by: ecolo127 | June 08, 2009 at 12:32 PM
There are news about giant "solar towers"
Two new websites are dedicated to them and they are very complete!!!
Please have a look on:
www.solar-tower.org.uk
and www.tour-solaire.fr
(and next month www.torre-solar.es)
Cheers
ecolo127
Posted by: ecolo127 | June 08, 2009 at 12:33 PM