## Solar Systems to Build A$420 million, 154MW Solar Power Plant in Australia ##### 27 October 2006  An artist’s concept of the HCPV technology: the field of heliostats and the tower-mounted PV modules. A A$420 million (US$321 million), 154MW solar power plant—designed to be the biggest and most efficient solar photovoltaic power station yet in the world—is to be built in north-west Victoria, Australia by Australian company Solar Systems. The Victorian power station will meet the annual needs of more than 45,000 homes. The power station will use high-performance solar cells—originally developed to power satellites—that are three times more efficient than standard solar panels. Solar Systems has also developed the capability to concentrate the sun by 500 times onto those solar cells for ultra-high power output. The power station will use technology known as Heliostat Concentrator Photovoltaic (HCPV): fields of heliostats (sun-tracking mirrors) focusing sunlight on receivers. The receivers house photovoltaic (PV) modules, which consist of arrays of ultra high-efficiency solar cells that convert the sunlight directly into electricity. The heliostat control system, PV modules and cooling system designed to keep the solar cells running at 60° C are patented by Solar Systems. Solar Systems has been collaborating with Spectrolab, a Boeing Company, on the optimization of the Spectrolab multi-junction solar cells for use in Solar Systems’ existing CS500 dish systems. The two agreed in August to go into commercial production with the technology. This is a new generation of solar technology. The secret is to be able to make a solar power module work about 1,500 times harder than typical solar panels. If you can do this at high efficiency using low-cost materials, you have the recipe for an infinite supply of clean energy at an affordable price. This new power station will demonstrate these principles and produce the most affordable solar energy yet generated. —John Lasich, Solar System Technical Director The technical outcomes of the joint work were demonstrated in April when Solar Systems upgraded one of its CS500 dishes at a power station it operates in Hermannsburg (central Australia) from approximately 24kW to 35kW simply by replacing the existing silicon PV modules with the new MJ cell based modules. The process took only 2 hours and the output of the system increased by more than 50%. The Australian Treasurer Peter Costello announced a A$75 million grant to the project under the Federal Government’s Low Emissions Technology Demonstration Fund (LETDF). Solar Systems was one of more than 30 companies that bid for $500 million under the LETDF program, which aims to foster competitive technology that will significantly reduce greenhouse gas emissions. The Victorian Premier Steve Bracks announced that the Victorian Government will also support the project with a grant of$50 million.

Solar Systems will build the power station across a number of different sites, and has formed a new company—Solar Systems Generation Pty Ltd—to construct the station.

The Victorian project is the first phase of a plan to deploy more than 1,000 MWs across Australia, China and the United States in a A$2.5-billion project under the Asia-Pacific Partnership on Clean Development and Climate. (A hat-tip to Rafael Seidl!) ### Comments San Diego Gas and Electric wants to put 300 megawatts of Stirling dishes out in the desert and run high voltage lines through a park. They could put acre plots of CPV around San Diego County and get power without the lines through the park. http://www.sdge.com/sunrisepowerlink/release3.shtml SJC - very interesting, that is a very large scale project for solar power. Practical stirling engines can achieve efficiences comparable to diesels, albeit at a much higher purchase price. Having solid-state PV/TPV and stirling technology compete for large-scale projects should spur innovation and sharply reduce cost per kWh. SDG&E wants the transmission lines through the park because that is the cheapest route. They want the lines to bring nuke power from Palo Verde on the AZ border. The solar part is just an excuse. They have no intention of building the program. Guys there was a solar chimney in france that was a scaled down version of environmission. I functioned for years. I proved that the concept works. I don't get why photo-voltaics and sterling engines have to compete. Why not develop a sterling engine with a photovoltaic cell inside a glass chamber? Concentrated sunlight would hit the PV cell converting 25 to 30% of sun rays in electricity. The other 75 to 70% of sun rays would be converted to heat that would be trapped inside the glass evelope. This heat energy can then be converted to electricity by the sterling engine with an efficiency of about 30%. In short, you get 30%(PV)+ 30% of 70%(for the sterling engine) = 51% efficiency. An now for the finale. Heat engines must reject some heat to produce work (basic thermodynamics). So lets put a heat exchanger on that theoretical sterling engine and recover some of that 49% of waste heat so that we can heat water for free. solar water heaters can recover 70% of sun energy. Lets say for the sake of argument that the energy quality of the 49% of waste heat is so low that only 40% of it can be recovered. Now we can cheaply build a home system at a much smaller scale with about 20 square meters of concentrating mirrors to be placed in the back of a house. At 1000 Watts/square meter for sun light, we have 20000 Watts of solar energy: - 30% is captured by the PV, therefore we have 6000 Watts of electricity for 6 to 8 hours a day (36 to 48 KW*hr per day) - 30% of the remaining 70% is captured by the sterling engine, therefore we have 4200 Watts of electricity for 6 to 8 hours a day (25.2 to 33.6 KW*hr per day - 40% of the 49% of the rejected heat that is left, therefore we have 3920 Watts of recovered heat for 6 to 8 hours a day (23.52 to 31.36 KW*hr a day). This is enough heat to raise the temperature from 25 Celcius to 80 Celcius for about 96 to 128 gallons of watter a day. If this is too much water for an average family, no problem: Heat the house during winter (another heat exchanger), reject the rest during summer. Total Electric energy saved could go from (36+25.2+23.52) KW*hr = 84.72 KW*hr to (48+33.6+31.36)KW*hr = 112.96 KW*hr. To be concervative, I'll take the low figure. At 8 cents per KW*hr, that would be$6.78 a day, or about \$200 a month.

Interesting idea, Freddy, but I don't think it would work. The problem is that the PV cells are not transparent to the wavelengths that they don't don't convert. Maybe they could be thinned down enough for non-converted wavelengths to pass through, but as it is, I think those wavelengths are absorbed as heat.

Maybe somebody who knows more about the optics of PV materials could comment?

The concept presented in this article, of a tower and field of heliostats, but with high efficiency PV conversion rather than thermal, is intriguing. Having the PV cells concentrated in a small area makes both cooling and power collection a lot easier. At the same time, using PV instead of thermal avoids a number of difficulties that beset thermal towers. It isn't necessary to focus as much sunlight as possible on as small an aperture as possible in order to minimize losses from black body radiation. So the heliostat field can be sparse, and the heliostats can be much cheaper.

Heliostats of this type can be mounted on an open space frame "roof" above pastures and agricultural fields. The partial shading that they provide to the fields won't reduce productivity for many types of crops,and it will improve it for some.

It takes a large amount of energy to produce a solar cell.

They are a very simple device though, they are just a PN junction with electrical contacts on them. So easy to make that I made a few of them in college.

I and my lab partners made a few single crystal Si solar cells, ours will never produce more power than it took to make them. Weather or not this is the case for comercial cells I can't say.

A quick run down on how to make a solar cell.
To start off you are going to need some very pure Si.
This is made by well melting sand ... the melting point of Si is up there.

Ok so say you have your super super pure Si now you are going to melt it again and add contaminants to it to get the properties you want. You'll dip a seed crystal into the liquid Si goo and pull it out slowly. this forms a single crystal with the structure oreineded the way you want and hopefuly with very few defects in the crystal.

once your cystal is done it is cut into wafers, you select the wafers with the correct mix of dopants in them. (the dopant concentration changes in the length of the crystal)

Now take your wafers and you want to make a PN junction so you apply more dopants to the surface and put them in an oven for an hr or so ... only this oven makes your home oven look like an ez-bake. It is very hot ... not as hot as the liquid Si mind you but still.

ok now your diffusion is done you have a Pn junction, clean up the waffers and now deposit a thin Al coatin on them in a Vac chamber. Now etch most of it off leaving only thin wire contacts on the surface.

Test your solar cell
If you did all your math right and you got lucky you now have a solar cell that produces ~.5V in full sunlight.

wooo hooo

connect a bunch of them in series to get more voltage and a bunch more to get more current

http://britneyspears.ac/physics/fabrication/fabrication.htm

Now you Know EVERYTHING!

RJ,
Quite an idiosyncratic link. Nice DIY, though I'm not sure many have access to that type of equipment.

These devices are made with gallium and germanium and not silicon. The answer to the thermal idea is yes, they can make IR transparent multi junction cells and have made a hybrid using JXCrystal's IR semiconductors and multi junction cells to turn the IR into moving electrons. So, the PV with stirling idea may be possible.

Rafeal, I agree in general with your comments on Enviromission and their solar tower. That said, their original 200 MW for 200,000 homes claim is no out of line. The tower is to operate 24 hours/day vs. 6-7 effective hours/day for PV systems. A MW of solar tower capacity thus supplies about 3.5x as many homes as a MW of PV capacity.

I don't know why they claim 100k homes for the new 50 MW design. Maybe it operates 48 hours/day!

There are other chemical compounds that make efficient photovoltaic semiconductors, like InGaN. DARPA is onboard:
http://compoundsemiconductor.net/articles/magazine/12/10/5/1

Special for "Silverthorn":

http://www.ecn.nl/docs/library/report/2006/rx06016.pdf

Energy payback times for Si-based PV-technologies haven been optimized (date of publication) up till 1.5 to 3.5 years, depending on location of PV-modules in south or middle Europe. Developments in this field (as well with respect total LCA scores) go extremely fast, and the end is not in sight. Also different technologies rising, without need of sawing (eg: risk of breaking ever thinner) wafers. Solar Fabrik in Freiburg (Germany) has been designed such that their climate impact is CO2 neutral. Solar is the future!

Besides, I agree with many parties on the fact that all REALLY sustainable technologies should be given a fair chance (for years to come), because we will need them all...

Having only 10 "old" Shell Solar modules (total 1,02 kWp), I produce 70% of my own electricity consumption. Reducing energy squandering FIRST, than buy those PV-panels. Success ensured.

The Australian project is OK, but why should Australian households consume 6.000 kWh/year (USA citizens often consume much more)? Average in the "cold" Netherlands is 3.500/year, I consume only 1.200 (INCLUDING self-generated solar electricity) and have a comfortable life.

Has any1 worked out the area required to produce 1 MW using this pv technology?

in reply to SJC...

You spoke of a chimney in France.

Are you thinking of THEMIS power plant? If yes, as part of the development team, I can tell you it's not a chimney, it's a concentrator solar plant supplying steam to a convetional steam turbine.

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