Solar Thermal power touted as energy solution
Australian scientists have developed a new way of producing electricity, which could provide all of Australia's electricity needs in 2020.
It has been developed by mixing solar energy, heat and natural gas.
Two hundred mirrors track the sun, and focus the sun's rays towards a tower.
The heat can reach temperatures of more than 1000 degrees Celsius, producing 500 kilowatts of power.
This is then mixed with natural gas and water to produce a renewable energy.
The article does not give the technology justice, you see, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) opened up their
testbed for solar and thermal energy a few days ago, on March 31st of 2006. This National Solar Energy Center (NSEC), although it is only meant to
test the technologies, the array can produce enough power for 100 homes.
The NSEC consists of three main elements
• A high concentration tower solar array that uses 200 mirrors to generate more than 500kW of energy. It will be capable of achieving peak
temperatures of over 1000°C;
• A low concentration linear solar array that generates a hot fluid at temperatures around 250°C; and
• A control room facility that will house the centre's communications and control systems and serve as an elevated viewing platform.
The NSEC represent two different forms of solar energy generation. The high concentration mirror array provides the energy needed to create "Solar
Gas", which is the leading reason for the development of this array.
The high concentration array will be used to provide the temperatures needed to produce a solar gas that contains over 25 percent more energy than
the natural gas feeding into the process. This solar gas can then be processed to solar hydrogen. Solar gas and solar hydrogen provide all the
benefits of solar energy but with all the convenience of gas. It enables solar energy to be stored and transported. The technology serves as a
transitional route toward higher levels of solar penetration into the energy mix.
The promise of this technology is that it "Combines Australia's two most abundant resources-Natural Gas and Sunlight". That is,unfortunately, all
I can find on the production of 'Solar Gas' along with the diagram below. If there are any members out there which have more information on the
production and how CSIRO can create more efficient LNG, please feel free to enlighten me
. Another positive of this technology is that, in
addition to Solar Gas, hydrogen is also created in this process.
Production of Solar Gas- Source
The second form of energy, thermal generation, is much easier for me to comprehend, and is so for everyone I imagine. That's because the key element
is a chimeny, just like the one I had as a kid. Of course, it's a far cry from the cinder block wonder I had, but the idea is the same- a tube with
openings at either end.
The thermal collection operation relies on convection (hot air rising). The larger the chimney, the faster the air will rise and turn specially
designed wind turbines. Solar Panels store energy and heat inside special insulated retainers, which are released during the night time chills
(remember, energy demand is less at night).
Impression of NSEC-Source
The next generation of this thermal tower is already in the works (It has been for several years now, actually, construction is slated to begin later
this year), once again in Australia. Being championed by Enviromission
tower would stand 1km tall, produce 200 Megawatts (enough to power 200,000 homes), and keep 900,000 tons of greenhouse emissions out of the atmosphere
. The main limiting factor is the cost, projected to be between 500-750
million dollars, with a ten year return on investment (read-Government support will be needed) I suspect that if you compare that with the long term
social costs of coal, LNG, or nuclear power, this Solar Tower would be the bargain. Here are a few interpretations of the solar tower project.
There are a few other types of solar power generation types, and they are of a solar thermal type. The SEGS system in California is of the first type,
known as a Parabolic trough.
As you can see, the name is derived from the shape of the mirrors. They are designed so that light is parabolically reflected onto the tube above the
mirror. The tube has a fluid pumped through it, which is heated and then used to produce steam for a turbine.
"Power Towers"are similiar to the NSEC mentioned before. The heliostats (moving mirrors) focuse solar light at a receiver, which heats up a transfer
fluid or metal to produce the steam needed for a turbine. While neither of these setups can operate during the evening, there is the ability, with
solar panels, to cache away heat for use during the night.
The utilization of this technology should be quickly evident. Apart from Australia, there are three areas which are perfect for construction of such
towers and LNG converters. The two greatest energy consumers, China and the United States, both have within their borders extensive deserts which can
be harnessed for their copious sunlight.
China, having already signed contracts to build Solar Towers, and measures 1,300,000 km2. The Mojave desert in the southwestern United States covers
35,000 km2, and it is estimated that solar power can generate 600 GW once the area reaches it's full potential. Let alone full development of the
9,000,000 km2 sahara desert, which could theoretically provide 245 terawatts of energy. The energy consumption of the whole world is about 13
A little light reading
[edit on 2-4-2006 by TheGoodDoctorFunk]