Saturday, June 27, 2009

numeraous energy source

Throughout the years, a number of attempts were made to refine the technology and construct a practical prototype of an OTEC plant. D’Arsonval’s student, Georges Claude, was the first to succeed in building an OTEC plant in Cuba in 1930, which was capable of generating 22 kW of electricity using a low-pressure turbine. This experiment proved the viability of such a system or, in Claude’s words “Made my virulent opponents hold their tongues.” Five years later, Claude constructed another OTEC plant aboard a cargo vessel. Unfortunately, it was destroyed shortly after the vessel departed due to poor weather conditions. The appearance of large amounts of cheap oil in the mid-twentieth century eventually brought OTEC research to a halt.

Ocean Thermal Energy Conversion (Credit: National Renewable Energy Laboratory)A team of British architects, including Dominic Michaelis, Alex Michaelis, and Trevor Cooper-Chadwick, are currently working on a project they hope will bring the century-old idea back to life. They have proposed to construct a network of “floating platforms”, which in addition to being OTEC power generators, will be equipped with wind and wave turbines. In this way, the platforms will simultaneously exploit a number of natural energy sources to provide ‘around the clock’ electricity. The scientists say that a single “island” of this design will be able to produce around 250MW, while 50,000 of these "islands" will be able to meet the daily energy requirements of the entire world's population.
The architects say that an OTEC plant will not only be a supplier of green energy, but due to its unique conversion process, will also provide desalinated water as a byproduct. In addition to about 300,000 liters of fresh water each day, the OTEC plant may also be used to produce hydrogen fuel by using electrolysis. Alex Michaelis envisions the islands themselves as home to workers, who will operate and maintain the plants. Michaelis envisions the inhabitants will be able to grow seafood and vegetables, living and working in rotations on the islands.

Sea solar power plant concept (Credit: Sea Solar Power International)Many critics have questioned the viability of the 50,000 artificial islands system, saying it is unlikely that the project can be implemented cost-efficiently. In response to this criticism, Michaelis says that "If we consider that we are at war to find a new form of clean energy, wartime effort in World War II produced vast numbers of planes, tanks, ships and other armaments on both warring sides. 20,300 Spitfires alone were built, making the construction of more than 50,000 of these plants seem a reasonable number."
TFOT previously covered a number of unique renewable energy technologies, including “EnviroMission’s” Solar Tower and JAXA’s project to build the world’s first space-based power generation system. You can also check out our article about “nano flakes” – a newly discovere

hydrogen flight


During the flights, the pilot of the experimental airplane climbed to an altitude of 1,000 meters above sea level using a combination of battery power and power generated by hydrogen fuel cells. After reaching the cruise altitude and disconnecting the batteries, the pilot flew straight and level at a cruising speed of 100 kilometers per hour for approximately 20 minutes solely on power generated by the fuel cells. Although the takeoff required the use of a regular engine, it is still considered by many in the industry as a remarkable feat.

A fuel cell is an electrochemical device that converts hydrogen directly into electricity and heat with none of the polluting products of combustion such as carbon dioxide. Other than heat, water is its only exhaust. This makes it a good substitute for conventional engines used today. According to Boeing researchers, PEM fuel cell technology could potentially power small manned and unmanned air vehicles. In the future, solid oxide fuel cells could be applied to secondary power-generating systems, such as auxiliary power units for large commercial airplanes. Although Boeing does not envision that fuel cells will ever serve as the primary power for large passenger airplanes, the company will continue to investigate the potential of this technology as well as other sustainable alternative fuel and energy sources, all in the name of environmental protection.


20 minutes on fuel-cell
power (Credit: Boeing)

The recent achievement was made thanks to the collaboration between Boeing Research & Technology Europe (BR&TE) in Madrid and industry partners stationed all around the world: in Austria, France, Germany, Spain, the United Kingdom, and the United States. The international team is quite proud of their work. Francisco Escarti, BR&TE's Managing Director, recently said: "We are proud of our pioneering work during the past five years on the Fuel Cell Demonstrator Airplane project. It is a tangible example of how we are exploring future leaps in environmental performance, as well as a credit to the talents and innovative spirit of our team." Indeed, this accomplishment encourages future tests that will set new marks in aviation.

TFOT has also covered the Zephyr, a solar-powered unmanned aerial vehicle which holds the world record for the longest-duration unmanned flight, and the SkyWatcher, a new type of Unmanned Aerial Vehicle tha can also be manned if necessary. Other related stories are the Air Car CityCat, which is equipped with a revolutionary dual-energy compressed air engine, and the Evolution, a unique aircraft that can travel on land, water, and air.

Fore more information about the Fuel Cell Demonstrator Airplane project, see Boeing's website.

As a result of these limitations there is a need for a new standard which will enhance the existing standards for wireless broadband and give a broadband experience as it was meant to be: pervasive, mobile, fast, and cheap. This is where WiMAX comes into the picture. WiMAX tries to take the best part of cellular network access – the part that allows you to easily connect anywhere within your service provider’s wide coverage area – and to take the best part of your Wi-Fi experience - the fast speeds and a familiar broadband internet experience - and combine them into a new wireless standard. This new wireless standard is based on the IEEE 802.16 standard (also called WirelessMAN), and was named by the WiMAX Forum which was formed in June 2001 to promote conformance and interoperability of the new wireless standard. It is common to divide WiMAX into two sub-standards, one for fixed wireless data transmission, known as "fixed WiMAX" (based on 802.16d), and the other, known most commonly today as "mobile WiMAX" (based on 802.16e). Mobile WiMAX includes some improvements over fixed WiMAX by also supporting mobility futures. Throughout this article, the notation WiMAX will be used to designate the more advanced mobile WiMAX.

WiMAX is an enhanced broadband standard with mobile features which enables continuous connectivity and offers wide coverage. With WiMAX support of multiple antennas at a single base station and sometimes at the subscriber unit, the coverage of a single base station can reach tens of kilometers and the data throughput can increase by four times to tens of Mbytes/sec, compared to only a few Mbytes/sec using the most advanced cellular 3.5G technologies. The Third Generation Partnership Project, targeted the UMTS mobile phone standard to cope with future technology evolutions, suggested a competing standard to WiMAX called “Long Term Evolution” (LTE). Both LTE and WiMAX can be seen as pre-4G technologies and the technological differences between them are small as they both work on the same bandwidth and try to provide solutions to the increasing demand for enhanced broadband services with the most advanced wireless technology existing today. As Wi-Fi is already widely deployed and works effectively inside buildings (indoor), WiMAX is expected initially to co-exist with Wi-Fi (connect to and between Wi-Fi hotspots) and to be used in areas where it is more effective than Wi-Fi. WiMAX, as a broadband wireless technology, can also be used as an alternative to cable and DSL as a “last mile” broadband access, mainly in rural areas where there is no wired structure