Skip to main content

Home/ qmstech2/ Contents contributed and discussions participated by dpurdy

Contents contributed and discussions participated by dpurdy

dpurdy

Wind Program: Advantages and Challenges of Wind Energy - 1 views

  • Challenges Wind power must compete with conventional generation sources on a cost basis. Depending on how energetic a wind site is, the wind farm may or may not be cost competitive. Even though the cost of wind power has decreased dramatically in the past 10 years, the technology requires a higher initial investment than fossil-fueled generators. Good wind sites are often located in remote locations, far from cities where the electricity is needed. Transmission lines must be built to bring the electricity from the wind farm to the city. Wind resource development may compete with other uses for the land and those alternative uses may be more highly valued than electricity generation. Although wind power plants have relatively little impact on the environment compared to other conventional power plants, there is some concern over the noise produced by the rotor blades, aesthetic (visual) impacts, and sometimes birds have been killed by flying into the rotors. Most of these problems have been resolved or greatly reduced through technological development or by properly siting wind plants.
dpurdy

Wind Program: History of Wind Energy - 2 views

  • Since early recorded history, people have been harnessing the energy of the wind. Wind energy propelled boats along the Nile River as early as 5000 B.C. By 200 B.C.,
  • Commonly called wind turbines, these machines appeared in Denmark as early as 1890. In the 1940s the largest wind turbine of the time began operating on a Vermont hilltop known as Grandpa's Knob. This turbine, rated at 1.25 megawatts in winds of about 30 mph, fed electric power to the local utility network for several months during World War II.
dpurdy

Fuel Cells - Electrochemical Power - 1 views

  • Hydrogen as the Main Fuel of the Future Over the last decades hydrogen, (H2) has gained more and more attention as an environmentally friendly fuel and storage medium. Combustion of pure hydrogen produces only water as exhaust. Hydrocarbon and carbon oxide emissions can only come from motor oil in the combustion chamber. Nitrous oxide emissions result from the nitrogen content in the air and increase exponentially with the combustion temperature. By using H2 in fuel cells, practically no pollution occurs. In this respect, hydrogen offers emission levels that are much lower than existing and future standards.
  • Hydrogen is the most common of all elements in the universe.
  • The desire for a long-term transition to a hydrogen society is mainly based on the need to reduce polluting and climate-affecting emissions and the concern about depletion of fossil fuel resources. Today about 90 % of the world's energy consumption is covered by fossil fuels, and most of this comes from a limited number of regions in the world. Even if hydrogen will be used on a large scale in the future, there is still a need for an energy source to produce it. Renewable energy technology such as hydro electricity, wind, wave and solar power are in principle available, but are not yet mature for mass production and/or fully developed. 
dpurdy

Fuel Cells - Electrochemical Power - 0 views

  • Fuel Cell Principle A fuel cell is an electrochemical energy converter. It converts chemical energy into electrical energy by two separated electrochemical reactions. In a hydrogen-fuelled polymer electrolyte membrane fuel cell (PEMFC), hydrogen is oxidised to protons and electrons at the anode. Protons migrate through the membrane electrolyte to the cathode. As the membrane is an electric insulator, electrons are forced to flow in an external electric circuit. At the cathode, oxygen reacts with protons to produce water, which is the only waste product
dpurdy

EIA Energy Kids - Hydrogen - 2 views

  • Like electricity, hydrogen is a secondary source of energy. It stores and carries energy produced from other resources (fossil fuels, water, and biomass).
  • ydrogen is the simplest element. Each atom of hydrogen has only one proton. It is also the most plentiful gas in the universe. Stars like the sun are made primarily of hydrogen. The sun is basically a giant ball of hydrogen and helium gases. In the sun's core, hydrogen atoms combine to form helium atoms. This process — called fusion — gives off radiant energy.
  • Hydrogen gas is so much lighter than air that it rises fast and is quickly ejected from the atmosphere. This is why hydrogen as a gas (H2) is not found by itself on Earth. It is found only in compound form with other elements. Hydrogen combined with oxygen, is water (H2O). Hydrogen combined with carbon forms different compounds, including methane (CH4), coal, and petroleum.
  • ...6 more annotations...
  • Hydrogen has the highest energy content of any common fuel by weight
  • Like electricity, hydrogen is an energy carrier and must be produced from another substance. Hydrogen is not currently widely used, but it has potential as an energy carrier in the future. Hydrogen can be produced from a variety of resources (water, fossil fuels, or biomass) and is a byproduct of other chemical processes.
  • Steam reforming is currently the least expensive method of producing hydrogen and accounts for about 95% of the hydrogen produced in the United States. This method is used in industries to separate hydrogen atoms from carbon atoms in methane (CH4). But the steam reforming process results in greenhouse gas emissions that are linked with global warming.1
  • Electrolysis Creates No Emissions but Is Costly Electrolysis is a process that splits hydrogen from water. It results in no emissions, but it is currently an expensive process. New technologies are currently being developed.
  • Hydrogen fuel cells make electricity. They are very efficient, but expensive to build. Small fuel cells can power electric cars. Large fuel cells can provide electricity in remote places with no power lines.
  • Portable fuel cells are being sold to provide longer power for laptop computers, cell phones, and military applications.
dpurdy

Fuel Cell Markets - Advantages & Benefits of Fuel Cell & Hydrogen Technologies - 2 views

  • Advantages by Application Telecoms CHP Fuel Cell Generators Electric Vehicles - APU's and Range Extenders Fuel Cell Forklifts Marine Power Portable Power
dpurdy

HowStuffWorks "How the Hydrogen Economy Works" - 3 views

  • In the hydrogen economy, there is no storehouse to tap into. We have to actually create the e­nergy in real-time.
  • There are two possible sources for the hydrogen: Electrolysis of water - Using electricity, it is easy to split water molecules to create pure hydrogen and oxygen. One big advantage of this process is that you can do it anywhere. For example, you could have a box in your garage producing hydrogen from tap water, and you could fuel your car with that hydrogen. Reforming fossil fuels - Oil and natural gas contain hydrocarbons -- molecules consisting of hydrogen and carbon. Using a device called a fuel processor or a reformer, you can split the hydrogen off the carbon in a hydrocarbon relatively easily and then use the hydrogen. You discard the leftover carbon to the atmosphere as carbon dioxide.
  • To have a pure hydrogen economy, the hydrogen must be derived from renewable sources rather than fossil fuels so that we stop releasing carbon into the atmosphere. Having enough electricity to separate hydrogen from water, and generating that electricity without using fossil fuels, will be the biggest change that we see in creating the hydrogen economy.
  • ...2 more annotations...
  • In the future, barring some technological breakthrough, it seems likely that one of two things will happen to create the hydrogen economy: Either nuclear-power or solar-power generating capacity will increase dramatically.
  • The electrical-generation problem is probably the biggest barrier to the hydrogen economy
dpurdy

HowStuffWorks "How the Hydrogen Economy Works" - 0 views

  • The elimination of pollution caused by fossil fuels - When hydrogen is used in a fuel cell to create power, it is a completely clean technology. The only byproduct is water. There are also no environmental dangers like oil spills to worry about with hydrogen. The elimination of greenhouse gases - If the hydrogen comes from the electrolysis of water, then hydrogen adds no greenhouse gases to the environment. There is a perfect cycle -- electrolysis produces hydrogen from water, and the hydrogen recombines with oxygen to create water and power in a fuel cell. The elimination of economic dependence - The elimination of oil means no dependence on the Middle East and its oil reserves. Distributed production - Hydrogen can be produced anywhere that you have electricity and water. People can even produce it in their homes with relatively simple technology.
dpurdy

Fuel Cells 2000 : Hydrogen : Basics - 1 views

  • How much will Hydrogen fuel cost? The U.S. Department of Energy's Hydrogen, Fuel Cells & Infrastructure Technologies Program is working to achieve the following goals: By 2005, the technology will be available to produce hydrogen at the pump for $3.00 per gallon gasoline equivalent, and DOE wants to validate this technology by 2008.  By 2010, the price goal is $1.50 per gallon of gasoline equivalent (untaxed) at the station. Even $3 a gallon would save most of us money, since FCVs will be two to three times more efficient than internal combustion engine (ICE) vehicles.  If all the goals are met, FCVs offer the promise of energy at $1 a gallon - or less! 
dpurdy

Benefits of Fuel Cell Technology - 1 views

  • With low emissions of pollutants such as nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter as well as dramatically lower emissions of carbon dioxide (CO2),
dpurdy

HowStuffWorks "How Fuel Cells Work" - 0 views

  • CostChief among the problems associated with fuel cells is how expensive they are. Many of the component pieces of a fuel cell are costly.
  • InfrastructureIn order for PEMFC vehicles to become a viable alternative for consumers, there must be a hydrogen generation and delivery infrastructure. This infrastructure might include pipelines, truck transport, fueling stations and hydrogen generation plants
dpurdy

Fuel Cells - Electrochemical Power - 0 views

  • The best known early fuel cell experiments were performed in 1842 by the British physicist and lawyer, Sir William R. Grove (1811-1896)
  • Due to easily accessible and large amounts of oil and the invention of the combustion engine (Carl Friedrich Benz and Gottlieb Daimler), fuel cells were forgotten until the middle of the 20th century. In the US Apollo space programme, fuel cells exhibited their first renaissance in the 1960’s. 
  • Fuel cell development has been slowed down by a fear of hydrogen as a fuel. It is commonly believed that hydrogen is an extremely explosive and dangerous gas. Most of this belief was founded in 1937, when the hydrogen-filled zeppelin “Hindenburg” caught fire and crashed in Lakehurst, USA.
dpurdy

Fuel Cells - Electrochemical Power - 1 views

  • One of the first applications for fuel cells based on their advantageous properties was in the US space program.
  • Compared to IC engines, fuel cells have practically no polluting exhaust like NOx and sulphides.
  • It is generally acknowledged that the feasibility and durability of fuel cells in automobiles has been proven. The major focus now is on cost reduction
dpurdy

EIA Energy Kids - Hydropower - 1 views

  • Tides are caused by the gravitational pull of the moon and sun, and the rotation of the Earth. Near shore, water levels can vary up to 40 feet due to tides. Dam of the Tidal Power Plant on the Estuary of the Rance River, Bretagne, France Source: Stock photography (copyrighted) Tidal power is more predictable than wind energy and solar power. A large enough tidal range — 10 feet — is needed to produce tidal energy economically.
  • The United States has no tidal plants and only a few sites where tidal energy could be produced economically. France, England, Canada, and Russia have much more potential to use this type of energy.
  • Tidal turbines are basically wind turbines in the water that can be located anywhere there is strong tidal flow. Because water is about 800 times denser than air, tidal turbines have to be much sturdier than wind turbines. Tidal turbines are heavier and more expensive to build but capture more energy.
  • ...2 more annotations...
  • Waves are caused by the wind blowing over the surface of the ocean. There is tremendous energy in the ocean waves. It's estimated that the total potential off the coasts of the United States is 252 billion kilowatthours a year, about 6% of the United States' electricity consumption in 2010. The west coasts of the United States and Europe and the coasts of Japan and New Zealand are good sites for harnessing wave energy.
  • Many more ways to capture wave energy are currently under development. Some of these devices being developed are placed underwater, anchored to the ocean floor, while others ride on top of the waves. The world's first commercial wave farm using one such technology opened in 2008 at the Aguçadora Wave Park in Portugal.
dpurdy

RenewableUK - Where Does Tidal Energy Come From? - 0 views

shared by dpurdy on 03 Nov 11 - No Cached
  • Where Does Tidal Energy Come From? The gravitational force of the Earth stops the ocean from floating off into space, just like everything else. The Moon also has a very weak gravitational effect on the Earth, which is not normally noticable as far as falling teacups are concerned, but the ocean, which can flow around the globe to even out differences, is noticably affected.
dpurdy

Winds, Waves, Tides - Ocean Energy | Environmental News, Articles & Information | Globa... - 2 views

  • Can Already Cost Under $.06 per Kilowatt Hour * Pneumatic devices, such as the oscillating water column (OWC), use wave motion to compress and decompress air, and drive a turbine. * Float-based devices utilise a buoyant float moving with the waves, reacting against a sea bed anchor in order to harness energy. * Spillover devices utilise wave height to replenish a reservoir of seawater, which runs a turbine. * Raft-type devices use the relative motion of adjacent rafts or pontoons to harness wave energy. * Moving-body devices articulate in the water, inducing motion, which may be used to drive a hydraulic motor.
  • Tidal stream devices extract energy from the diurnal flow of tidal currents (caused by the gravitational pull of the moon). Unlike wind and wave power, tidal streams offer entirely predictable output. However, as the lunar cycle is of around 25 hours’ duration, the timing of peak outputs differs by around an hour each day and tidal energy cannot be guaranteed at times of peak demand.
  • However, several large grid-connected demonstration projects are expected to enter the water in the near future. Tidal stream is thus a few years behind wave energy.
  • ...3 more annotations...
  • The manufacturers of all these devices expect to deliver energy at a cost of 10-14 US cents per kWh, falling to below 6 US cents as experience grows and technologies mature
  • Marine Current Turbines is about to field test a submerged 300 kW tidal turbine off Devon in the United Kingdom
  • Power generation using wave energy is at a much earlier stage of development. Wave energy offers more predictable outputs than wind, but in early 2003 there was only around one megawatt of generating capacity installed worldwide, all of it essentially with demonstration prototypes. Proposed projects are likely to take this to about 6 MW over the next few years. The wave industry is characterised by a wide variety of novel devices
dpurdy

Wave power - Wikipedia, the free encyclopedia - 2 views

  • Waves are generated by wind passing over the surface of the sea. As long as the waves propagate slower than the wind speed just above the waves, there is an energy transfer from the wind to the waves.
  • The first known patent to utilize energy from ocean waves dates back to 1799 and was filed in Paris by Girard and his son.[12] An early application of wave power was a device constructed around 1910 by Bochaux-Praceique to light and power his house at Royan, near Bordeaux in France
  • Once the wave energy is captured at a wave source, power must be carried to the point of use or to a connection to the electrical grid by transmission power cables.[2
  • ...2 more annotations...
  • The realistically usable worldwide resource has been estimated to be greater than 2 TW.[49][50] Locations with the most potential for wave power include the western seaboard of Europe, the northern coast of the UK, and the Pacific coastlines of North and South America, Southern Africa, Australia, and New Zealand. The north and south temperate zones have the best sites for capturing wave power. The prevailing westerlies in these zones blow strongest in winter. Waves are very predictable; waves that are caused by winds can be predicted five days in advance.[citation needed]
  • There is a potential impact on the marine environment. Noise pollution, for example, could have negative impact if not monitored, although the noise and visible impact of each design varies greatly.[5]. Other biophysical impacts (flora and fauna, sediment regimes and water column structure and flows) of scaling up the technology is being studied.[51] In terms of socio-economic challenges, wave farms can result in the displacement of commercial and recreational fishermen from productive fishing grounds, can change the pattern of beach sand nourishment, and may represent hazards to safe navigation.[52] Waves generate about 2,700 gigawatts of power
dpurdy

OWECO By Others - 1 views

  • ocean waves is long considered substantive kinetic resource
dpurdy

Wave Energy Wave Power Clean Renewable Electricity Generation - Wavegen - 1 views

  • Ocean waves are a tertiary form of solar energy, in that unequal heating of the Earth’s surface generates wind, and wind blowing over water generates waves. Despite the fact that nearly 75% of the Earth’s surface is covered with water, waves are a largely unexplored source of energy, compared with the progress that has been made in harnessing the sun and wind.
« First ‹ Previous 181 - 200 of 218 Next ›
Showing 20 items per page