• Rpidly increasing bandgap with decreasing quantum dot size,
Monday, December 26, 2011
• Rpidly increasing bandgap with decreasing quantum dot size,
Thursday, December 22, 2011
Ref: Science Daily
Friday, December 16, 2011
Sunday, December 11, 2011
Tremendous achivement is there in India in terms of capacity addition in Wind Energy. Based on some reliable sources, around 1411 MW wind power capacity has been added in India during the period from April-2011 to Sept-2011 of the FY 2011-12 which is the highest capacity addition during the first half of any Financial year in India.
1. Andhra Pradesh - 11.50
2. Gujarat - 251.00
3. Karnataka - 93.30
4. Madhya Pradesh - 54.20
5. Maharashtra - 150.80
6. Rajasthan - 226.35
7. Tamilnadu - 624.30
Total - 1411.45
Wednesday, December 07, 2011
Aggressive bidding has taken place at the JNNSM Phase 1 Batch II. A very aggressive bidding round was seen at the Scope Complex Auditorium for the Batch II of Phase 1 of the Jawaharlal Nehru National Solar Mission (JNNSN). Solar Direct Emerges was the lowest bidder at Rs.7.49/kWh, while Green Infra was the highest bidder at Rs.9.39/kWh.
There can be a number of arguments to justify the low bid prices, but we have to wait and see that how these companies are achieving financial closures with these lower tariffs.
Now the challenge is to accomplish the projects as per the schedules after signing the PPAs. Of course, most of these developers can benefit from their previous experience in India in setting up Solar Photovoltaic Projects. I am sure that Solar will overtake Wind Energy sector in India if this enthusiasm and spirit prevails which can replace several tons of carbon dioxide otherwise would have produced with fossil fuel based power plants.
Wednesday, November 30, 2011
Ref: University of Texas at Austin (2007, October 19). Dealing With Wind
Variability On The Wind Farm. ScienceDaily. Retrieved November 30,
Sunday, July 31, 2011
Saturday, June 25, 2011
Currently, with solar plants accounting for a very small fraction of generation on most electrical grids these changes do not cause any problems for grid operators. However, if solar penetration levels increase in the future, as they likely will, such variability will pose problems for grid operators. A fast change in generation from cloud transients will need to be balanced by other sources of generation to balance load.
The power output fluctuations from solar panels during the cloud cover have to be predicted for addressing this issue. We hope that the latest innovation from the Department of Mechanical and Aerospace Engineering at the Jacobs School, San Diego can solve the problem to a greater extent.UC San Diego Professor Jan Kleissl and Matthew Lave, a Ph.D. student in the Department of Mechanical and Aerospace Engineering at the Jacobs School, have found the answer to these questions. They also have developed a software program that allows power grid managers to easily predict fluctuations in the solar grid caused by changes in the cloud cover. The program uses a solar variability law Lave discovered.
But Kleissl and Lave found that variability for large photovoltaic systems is much smaller than previously thought. It also can be modeled accurately, and easily, based on measurements from just a single weather station.
The finding comes at a time when the Obama administration is pushing for the creation of a smart power grid throughout the nation. The improved grid would allow for better use of renewable power sources, including wind and solar.
Also, more utilities have been increasing the amount of renewable energy sources they use to power homes and businesses. For example, Indian Ministry of New and Renewable Energy have come up with National Solar Energy Mission to add 20000 MW by 2020. Inspired by this announcement many MNCs and Indian companies have come up with proposal for solar farms.
Kleissl and Lave's finding could have a dramatic impact on the amount of solar power allowed to feed into the grid. Right now, because of concerns over variability in power output, the amount of solar power flowing in the grid at residential peak demand times in California, say -- is limited to 15 percent before utilities are required to perform additional studies. As operators are able to better predict a photovoltaic system's variability, they will be able to increase this limit.
Incidentally, Kleissl and Lave's research shows that the amount of solar variability can also be reduced by installing smaller solar panel arrays in multiple locations rather than building bigger arrays in just one spot, since a cloud covering one panel is less likely to cover the other panels, Lave said. "The distance between arrays is key," he said.
Kleissl presented the paper, titled 'Modeling Solar Variability Effects on Power Plants,' this week at the National Renewable Energy Laboratory in Golden, Colo.
His findings are based on analysis of one year's worth of data from the UC San Diego solar grid -- the most monitored grid in the nation, with 16 weather stations and 5,900 solar panels totaling 1.2 megawatts in output. Lave looked at variations in the amount of solar radiation the weather stations were receiving for intervals as short as a second. The amount of radiation correlates with the amount of power the panels produce.
Based on these observations, he found that when the distance between weather stations is divided by the time frame for the change in power output, a solar variability law ensues. "For any pair of stations at any time horizon, this variability law is applicable" says Lave. In other words, the law can be applied to any configuration of photovoltaic systems on an electric grid to quantify the system's variability for any given time frame.
But Lave didn't stop there. He developed an easy-to-use interface in MATLAB that allows grid planners and operators to simulate the variability of photovoltaic systems. Data can be input as a text file, but the interface also allows users to simply draw a polygon around each system on a satellite Google Map. Based on solar radiation measurements at a single sensor on a given day, the model calculates the variability in total output across all systems.
"It is as easy as painting by numbers," said Kleissl. "In Google Maps, photovoltaics show up as dark rectangles on rooftops. Draw some polygons around them, push the button, and out comes the total variability."
Kleissl said he anticipates this tool will be useful to figure out whether problems in voltage fluctuation may occur in power feeder systems with a large amount of photovoltaic arrays. At this point, the solar installations on almost all feeders are still far below the capacity that would cause any major issues. The tool developed by Lave and Kleissl could become key in solar installations in all parts of the world.
The model development was sponsored by DOE's High PV Penetration Program grant 10DE-EE002055. Further information is available at:
https://solarhighpen.energy.gov/project/university_of_california_san_diego and http://solar.ucsd.edu
Wednesday, March 16, 2011
Conditions at a stricken nuclear power plant in Japan have deteriorated so much that there is a growing consensus the crisis is greater than the Three Mile Island accident in 1979, and there are fears that it could get significantly worse.
All six reactors at the complex have problems; be it blown-out roofs, potentially cracked containment structures, exposed fuel rods or just the risk of explosion that has been great enough to force emergency measures. Of particular concern are a fire in a massive pool holding spent atomic fuel rods and a blast at the building housing the pool and reactor No.4. The pool is exposed to the elements, unlike the reactor core protected in steel and concrete.
The accident at the Three Mile Island nuclear plant in Pennsylvania in 1979 was the biggest in U.S. history. Half of the reactor core in one unit melted due to the loss of coolant, though it resulted in no immediate injuries.
The Chernobyl accident in Ukraine in 1986 was the worst in the industry's history, as an explosion led to a cloud of radioactive material being spewed over big parts of Europe.
Several experts said that Japanese authorities were underplaying the severity of the incident, particular on a scale called INES used to rank nuclear incidents. The Japanese have so far rated the accident a four on a one-to-seven scale against Three Mile at a five and Chernobyl at a seven.
But that rating was issued on Saturday, and since then the situation has worsened dramatically.
In the past few hours alone, the plant's operator Tokyo Electric Power Co, said that a fire broke out at the building housing the No.4 reactor -- the same reactor that houses the troubled spent fuel pool.
Kyodo News reported, citing TEPCO, that the fuel rods in the No. 1 reactor were 70 percent damaged and the rods in the No. 2 reactor were 33 percent damage. Meanwhile, just after 10 a.m. local time Wednesday, Japanese TV reported white smoke coming from the plant.
Separately, Japan's nuclear safety agency said two workers are missing and disclosed that there is a crack in the roof of the same building after an earlier explosion.
Europe's Nuclear Plan under Pressure
Japan's nuclear crisis in the wake of a huge earthquake is likely to increase opposition to plans for a major nuclear expansion in Europe and focus attention on the vast potential costs of a nuclear disaster.
The crisis will reignite concern over nuclear safety as Japan fights to avert a meltdown at crippled nuclear reactors, describing the quake and tsunami, which may have killed more than 10,000 people, as its biggest crisis since World War Two.
The disaster is a setback to the nuclear industry, which is enjoying a renaissance as public fears over nuclear safety have faded along with memories of the 1979 Three Mile Island accident in the United States and Ukraine's 1986 Chernobyl disaster.
Many countries plan new nuclear power plants, regarding nuclear as a clean alternative to expensive and dwindling oil and gas and saying new technology should allay safety fears.
But anti-nuclear campaigners around Europe have seized on the Japanese accident as evidence of the dangers of nuclear power and said governments should rethink plans for new plants.
"I think it will make a lot of governments, authorities and other planners think twice about planning power stations in seismic areas," said Jan Haverkamp, European Union policy campaigner for environmental group Greenpeace, which opposes new nuclear reactors and wants existing ones phased out.
French reactor maker Areva and nuclear power producers EDF and GDF Suez are important industry players. France's Alstom and Schneider Electric are also active in the sector, as are Switzerland's ABB and Germany's Siemens.
Chancellor Angela Merkel, whose government last year extended the operating lives of Germany's nuclear reactors, said the government was consulting with nuclear experts and watching the situation in Japan closely.
The Japanese radiation leak comes at a difficult time for Merkel, whose conservatives face three state elections in March where nuclear safety fears could help her opponents.
On Saturday, tens of thousands of anti-nuclear protesters formed a 45-km (27 mile) human chain from Stuttgart to a nuclear power plant that will be kept running longer because of the new policy. The protest was planned before the Japanese earthquake.
Oil will be needed to support Japan after the recent earthquake disaster. Russia has promise energy industry support to Japan, the easiest of which to implement is fuel. Clean up is going to take lots of horsepower from fuel. The Japanese electrical grid will be without electricity from nuclear generators for quite sometime. Bloomberg reported that Tokyo Electric is still seeking government approvals for a full restart of the Kashiwazaki Kariwa nuclear power plant (five reactors at 1,067 MW and two at 1,315 MW for a total 7,965 MW), which was shutdown after being damaged by an earthquake in 2007. The company posted its first loss in 28 years after it was forced to buy fossil fuels at record prices to make up for the lost nuclear output.
The Effect on Energy Industry
The 8.9 magnitude earthquake not only wiped out people's belongings in northern Japan, but also destroyed supply chains from various industrials. The nuclear power industry was especially hit hard due to the chain reaction resulting meltdown of the metal containers in the reactors. Numerous organizations and governments around world protect against nuclear energy as a major source of energy on this planet because it is simply not safe in such scale a disaster.
Countries such as USA, China, Japan and Australia are most susceptible to big earthquakes. It is reported that Southern California is way overdue for a big hit, it is not a question of "if" but "when." California has two operating plants: Diablo Canyon and San Onofre, both are vulnerable to earthquakes. This causes serious concerns in the region. Naturally, last week's earthquake changed the mentality of how people should approach renewable energy in the future. We will not likely give up nuclear energy, but the problem is that no safety rule is strict enough to guarantee safe operations if a big earthquake strikes. As a result, nuclear power will likely play a smaller role in the future energy market, while solar and wind energy are much more secure, safer and easy to distribute.
The Effect on Solar Industry
The earthquake also has impact on the solar energy industry. Japan accounts for 1/4th of global solar production, including solar panels and polysilicon. Most of these products are sold in domestic markets, some polysilicon is shipped overseas. The earthquake caused shutdown of production from Sanyo, Panasonic, the Kyocera Corp. and Sharp. Some facilities are not severely damaged, but what impacts the industry is the infrastructure. It is believed that at least 2-3 months will be needed to repair the power grid. Without electricity, the solar industry will remain shutdown for foreseeable future. The supply chain is not there any more. It will even take longer to repair the roads and ports in the northern coast.
Japan may have two weeks of inventory for panels and wafers. M. Setek, a solar wafer supplier, has completely shut down its facilities due to the damage caused by the earthquake. It supplies wafers to Sunpower. Companies benefiting the most are the polysilicon producers such as LDK solar and ReneSola. Both will fill the gaps left by Japanese companies. Sunpower, Sharp and Kyocera will likely have to place orders from LDK and SOL to solve the supply problem, and they may have to pay high price for the wafers. We believe Suntech power, Jinko Solar, and Trina Solar will not be affected by the shortfall, as they have long term contracts in place. Yingli green is a vertical integration company, so it is barely impacted.
The sentiment is shifting towards to solar energy as governments from Japan, China, France, Italy and Germany are considering boosting the solar energy shares in their renewable energy portfolios. People of these countries are putting lots of pressure on politicians to shift their energy policies to favor solar energy. In the next 2-3 months, new policies from the countries of major solar markets are expected to be enacted. The German government has indicated that existing nuclear plantoperations will not be extended as most Germans are opposed to nuclear power. It is certain that leaders in Japan will rigorously set policies to promote solar power as opposed to nuclear power in their next congressional meeting.
Saturday, February 26, 2011
The company Solaris Synergy believes that their invention provides cheaper electricity and better use of the land area.
Solar panels located on water surfaces have the advantage that they easily can be moved according to the sun’s movements and also prevent the water to the solar cells get too hot. A third advantage is that the water temperature is more constant than air temperature. Large temperature differences, such as in a desert is wearing much on solar cells semiconducting components, but this can be avoided by putting solar cells in water. The placement in freshwater prevents solar evaporation and inhibit algae growth.
Solar cells on water will probably be best placed on industrial ponds, for example at a water treatment plant where solar cells could then provide power to operate the treatment plant.
Developed by a Franco-Israeli partnership, this innovative solar power technology introduces a new paradigm in energy production. Solar power plays a dominant role in the world-wide effort to reduce greenhouse gases, it is considered a clean energy and is an efficient source of electricity. Yet several obstacles have been undermining the expansion of this sector and many of its actors are looking for a new approach towards the markets.
Soon after the design phase was over, at the end of March 2010, the fabrication of a prototype began and the team is now aiming to launch the implementation phase in September 2011. The tests will take place at Cadarache, in the South East of France, the site having a privileged position on the French electric grid and being close to a local hydro-electric facility providing the water surface to be used for the installation of the system. It will operate on-site during a period of nine months, while assessing the system's performances and productivity through seasonal changes and various water levels. The research team members believe that by June 2012, they will have all the information required to allow the technology's entry on the market.
As even leading photovoltaic companies struggle to find land on which to install solar power plants, the project team identified the almost untouched potential of solar installations on water. The water basins, on which the plants could be built, are not natural reserves, tourists' resorts or open sea; rather they are industrial water basins already in use for other purposes. By that, it is assured that the new solar plants will not have a negative impact on natural landscapes. "It's a win-win situation," declares Dr. Kassel, "since there are many water reservoirs with energy, industrial or agricultural uses that are open for energy production use."
After solving the question of space, the team also took on the problem of cost. "It sounds magical to combine sun and water to produce electricity, but we also have to prove that it carries a financial logic for the long run," explains Dr. Kassel. The developers were able to reduce the costs linked to the implementation of the technology by two means. First they reduced the quantity of solar cells used thanks to a sun energy concentration system based on mirrors, while keeping steady the amount of power produced.
Secondly, the team used a creative cooling system using the water on which the solar panels are floating. Thanks to this efficient cooling method, the photovoltaic system can use silicon solar cells, which tend to experience problems linked to overheating and need to be cooled down in order to allow the system to work correctly, unlike standard type more expensive cells. The particular type of solar cell used also allows a higher efficiency than the standard ones, achieving both reliability and cost reduction.
Still for the purpose of making the technology efficient and ready to market, the system is designed in such way that on a solar platform it is possible to assemble as many identical modules as needed for the power rating desired. Each module produces a standard amount of 200 kiloWatt electricity, and more power can be achieved by simply adding more modules to the plant.
The team also worked on the environmental impact of the technology. It works in fact as a breathing surface through which oxygen can penetrate to the water. This feature ensures that sufficient oxygen will maintain the underwater life of plants and animals. Dr. Kassel adds: "One of the implementation phase's goals is to closely monitor the possible effects of this new technology on the environment with the help of specialists" and "a preliminary check shows no detrimental environmental impact on water quality, flora or fauna. Our choices of materials were always made with this concern in mind."
*The project results from a collaboration between Solaris Synergy from Israel and the EDF Group from France. EUREKA provided the supporting platform which allowed to enhance both companies' partnership. After receiving the "EUREKA label" the project, called AQUASUN, found also support from the Israeli Ministry of Industry, Trade and Labor.