Posts Tagged ‘green energy’

Breakthrough in Thin-Film Solar Cells

Scientists at Johannes Gutenberg University Mainz (JGU) have come out with positive news about increased efficiency of thin-film solar cells. As we know that scientists are trying to increase the efficiency of the solar cells so that they can be considered as serious alternative to the fossil fuels. Researchers at Johannes Gutenberg University Mainz (JGU) too are working at this angle. They opted for the computer simulations to probe deeper into the indium/gallium combination to increase the efficiency of Copper indium gallium (di)selenide (CIGS) thin-film solar cells. Till now CIGS has shown only about 20% efficiency though theoretically they can attain the efficiency levels of 30%.

Advantages of CIGS:
CIGS cells are cheaper than their counterpart silicon cells due to lower material and fabrication costs resulting in lowered manufacturing costs. CIGS has direct band-gap material therefore they exhibit a very strong light absorption tendency, and only 1-2 micrometers of CIGS is enough to absorb most of the sunlight. Conventional silicon photovoltaic cells are rigid but CIGS cells are flexible. Thin-film solar cells are slowly topping the popularity chart of solar market.

Working on the Efficiency of CIGS: Currently CIGS cells are showing efficiency of around 20%. These cells absorb sunlight through a thin layer made of copper, indium, gallium, selenium, and sulphur. The scientists at Mainz University headed by Professor Dr Claudia Felser are exploiting the computer simulations to find out the properties of CIGS. This research is a part of the comCIGS project. This project is financed by the Federal German Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU). The researchers are concentrating on the optimum proportion of indium/gallium puzzle. What ratio of indium/gallium would be ideal to increase the efficiency of CIGS? It was discovered earlier that the desired ratio should be 30:70, in practice; the highest efficiency level has been obtained with the exactly opposite ratio of 70:30.

Christian Ludwig who is the member of the Professor Felser’s team worked on the calculations using a hybrid method. This hybrid method included a combination of density functional calculations and Monte Carlo simulations. Dr Thomas Gruhn is the head of the theory group in the Prof. Felser’s team. He says, “Density functional calculations make it possible to assess the energies of local structures from the quantum mechanical point of view. The results can be used to determine temperature effects over wide length scale ranges with the help of Monte-Carlo simulations.”

Homogeneity of the material is the key to high efficiency:
Scientists find out that the indium and gallium atoms are not distributed evenly in the CIGS material; there is a phase when indium and gallium are completely separate. This separation happens at just below room temperature. Researchers also tried out various combinations of temperatures and discovered that the higher the temperature, the more homogeneous the material becomes. The more the lack of homogeneity of the gallium-rich material the lower the efficiency levels of gallium-rich CIGS cells. This phenomenon is discovered for the first time by Prof Felser’s team. The team also discovered a better way to manufacture CIGS solar cells. The research team says if gallium rich material is produced at higher temperatures, the material is notably more homogeneous. For maintaining the homogeneity, the gallium rich material should be cooled down rapidly.

Glass is used as substrate for solar cells. Glass has always restricted process temperatures. But Schott AG has been successful in inventing a special glass with which the process temperature can be increased. Naturally the cells would be more homogeneous. This would lead to the production of cells with a much greater efficiency level. Gruhn says, “We are currently working on large-format solar cells which should outperform conventional cells in terms of efficiency. The prospects look promising.”

Flat Tower: Innovative Architectural Solution

High-rise buildings and skyscrapers have been the most favored architectural solutions for highly populated cities. It is a commendable idea for combining height – growing more vertically – and for its small footprint without hogging precious soil which is at a premium in most cities. But sporadic eruptions of skyscrapers do not add to the beauty of the skyline of any city nor does it add any way to the locale topographical charm. The solution seems to be structures that solve housing problem for the populace without spoiling the beauty of the city.

2011 eVolo Skyscraper Competition
The 2011 eVolo Skyscraper Competition is an annual event for architectural designs. This year’s goal was to find an architectural solution for housing in thickly populated urban areas without disturbing the existent city skylines as well as not hogging precious green spaces. This flat tower designed by Yoann Mescam, Paul-Eric Schirr-Bonnans, and Xavier Schirr-Bonnans from France has won the second place. This dome like structure has excellent green technology features incorporated as well.

Conforming to the guidelines
This high-dome building somewhat resembles a hillock on the outside and is about 800 meters in diameter. Honeycomb like gaps in the top surface let in the daylight so that the interior remains well-lit and gets plenty of sunlight. This is not a skyscraper but rather a hillock like structure with skylights built-in; covering vast areas of the city without attempting to destroy the existing structures or distorting the skylines.

Multi-level-structure
At the ground level of the structure, there will be facilities for entertainment as well as huge tracts of green space. At the higher levels, office premises and residential quarters will be housed. While enough sunlight gets through to all levels through the openings in the ceiling, there will be enough windows for light and air circulation. There will be automated transport system for commuting inside and in and out of the structure. Each unit will be designed optimally as per their programmed needs.

Green ethics
The dome-like roof will have enough provision to house all the solar panels that will be needed by the entire complex. Also arrangements will be there to harvest rain water for watering the green areas below the dome and also for domestic use making the structure energy efficient and water self-sufficient. The skylights in the dome will reduce the need for artificial lighting during daytime and the solar panels will ultimately make the structure depend less and less on fossil fuel.

Universal adaptability
The designers have planned this for Rennes, a city in the old industrial area of France. It is a medium-size city, not interested in skyscrapers or any skyline-distorting high-rise buildings. While retaining the ethnic beauty and topographical highlights special to this area, the dome is designed as a housing solution for this city for highly populated areas with green ethics in mind. This design can be adapted for any other similar sized city.

It is extremely heartening to see that more and more people are turning towards green and renewable energy for containing carbon and other footprints to have a better and more eco-friendly world for future generations. This flat tower is also one such attempt.

Generating Electricity from Wing Waves

Just like wind mills and wind turbines that generate power and electricity from the wind, scientists are now working to generate power from the sea. Stephen Wood, an assistant professor of marine and environmental systems at Florida Institute of Technology’s College of Engineering is working on this technology for its advance and proper use. This technology will use Wing waves in a very efficient way to generate electricity and power from the sea.

The wing waves technology to produce electricity and power from sea is a project initiated by a renewable energy firm from Tallahassee called the Clean and Green Enterprises. This firm has been working in this area since the past five years.

The use of Wing Waves to produce electricity from the sea
According Wood, about 200,000 houses can be lit with the help of one square miles of wings that produce around 1000 units of electric power. Power is generated by changing elliptical motion wave into mechanical energy after trapping it 30 feet to 60 feet below the sea.

The chief executive with Clean and Green Enterprises Inc., Terence Bolden says that the wings sway 30 degrees from side to side. They take 8 to 10 seconds to complete every arc. In this process, they produce electricity.

Basic requirements to use Wing Waves to produce electricity from the sea
To use Wing waves to produce electricity from the sea, there are two basic requirements: depth of 40 to 50 feet and a sandy bottom. Sea fans are placed on the sandy base. Though, bigger wings can be used to tap water to make electricity but for that the plant to make these wings has to be situated near the ocean. Till then, the fans having trapezoid-shaped wings that are 8 feet tall and 15 feet wide will continue to be used and they will be transported through road. The height and the width of the wings are carefully made so that they can be transported by the road and can be easily placed under the sea.

Advantages of using Wing Waves to produce electricity from the sea
An example of Wind Waves to produce electric power from the sea was showcased when two 8-foot-tall wing flaps moved up and down on the seabed, just a few miles away from the Fort Pierce Fla.

The advantages of Wing waves are:

  • It is a clean and green way to generate electric power.
  • It is an alternative way to provide power.
  • It protects sea life. Wings waves are very environment friendly as they do not cause any danger to the turtles and attract fish.
  • The power produced in the sea can be used on land by transferring the electricity from sea to land through cables.
  • The wing waves are a treat for the eye to see.
  • If these wings are properly maintained, they can be used up to 20 years.
  • The wings will operate and generate power even when the sea is a bit calm. The wings will get locked automatically during hurricanes, when the sea is rough.
  • Wing wave’s technology can operate in any coastal area.
  • Wing Waves also help in desalinizing sea water.

The prototype of Wing Waves technology
The prototype of wing waves that has been working from November 17 off the Florida coast is built with aluminum. It has helped to collect data on wave motion and other relevant matters. The prototype that is going to replace the one used now will be made from composite material that is more resistant to corrosion.

Hopefully, Wing waves will be a revolution in generating power and electricity from the sea.