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kramerjac99

The Physics of Tidal Energy - NYTimes.com - 0 views

green.blogs.nytimes.com/...the-physics-of-tidal-energy

tidal energy

shared by kramerjac99 on 11 Mar 13 - No Cached
  • a tidal energy project is moving ahead in Maine, with high costs but high hopes too. But the 180-kilowatt unit that the Ocean Renewable Power Company hopes to put under water next week is really just a first step. The big question is, how well will it withstand the force of the rushing water?
  • The region, the Bay of Fundy, is famous for strong tides, but the company has picked a spot called Cobscook Bay, where the current is relatively slow, an average of 5.8 knots, or 6.7 miles an hour. That is the speed at which the hardware will produce 180 kilowatts.
  • kramerjac99 on 11 Mar 13
     
    How it works, how fast the waves are
dpurdy

Discovery Kids :: Tell Me - How does a generator work? - 0 views

kids.discovery.com/...how-does-a-generator-work

fossil fuels convert fossil

shared by dpurdy on 19 Mar 13 - No Cached
  • . It does this by using a magnet that forces electrons to move along a wire at a steady rate while putting pressure on them.
coreyemi99

How Do PV Solar Panels Work - Solar - 0 views

www.reuk.co.uk/ow-Do-PV-Solar-Panels-Work.htm

convert

shared by coreyemi99 on 20 Mar 13 - No Cached
  • When a visible light photon strikes a solar cell it can do one of three things: pass straight through, be reflected, or be absorbed. If the photon is absorbed, its energy is absorbed by an electron in an atom of the solar cell enabling it to escape from its normal position (photon excitation), cross the junction and fill a hole. Since electrons are physically moving across the PN junction, the positive charge carrying holes are effectively moving in the opposite direction around the load circuit (a rechargeable battery or light bulb etc). This completes the circuit providing more holes for the electrons to combine with and providing usable electricity.
dpurdy

How Wind Works | Wind Energy Foundation - 0 views

www.windenergyfoundation.org/...how-wind-works

wind form

shared by dpurdy on 24 Mar 13 - No Cached
  • Wind is simply air in motion. It is caused by the uneven heating of the Earth's surface by the sun. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates. One example of this uneven heating can be found in the daily wind cycle.
  • Mechanical or electrical power is created through the kinetic energy of the wind.
dpurdy

How Does Tidal Power Work? - Energy Informative - 1 views

energyinformative.org/how-does-tidal-power-work

tidal potential

shared by dpurdy on 03 Nov 12 - No Cached
  • 450 TWh is the estimated yearly potential of electric power that can be produced from tidal energy. In addition to this comes a large and not yet estimated potential in river flows.
  • Tidal stream generators are very similar to wind turbines except their below the water surface instead of above or on land. The turbine and generator converts the movement of water coming from change in tide, the kinetic energy, into electricity. Water is 830 times denser than air and therefore can generate electricity at lower speeds than wind turbines.
rutaemi98

How Fuel Cells Work | ClearEdge Power - 1 views

www.clearedgepower.com/...how-fuel-cells-work

transported fuel cells

shared by rutaemi98 on 22 Oct 12 - No Cached
  • About the size of a refrigerator, the ClearEdge Plus fuel system hooks up to your natural gas supply and through its fuel processor, draws the hydrogen molecules out. Then, through an electrochemical process that combines the hydrogen molecules with oxygen, the unit generates up to 5kW of electricity for use throughout your entire home and allows you the control to select specific critical circuits you want to remain "up" even when the grid is "down."
demboskiemm00

How long has solar power been around and does it work? - An eNow Blog Article - 0 views

www.enowenergy.com/...r-been-around-and-does-it-work

solar history

shared by demboskiemm00 on 22 Oct 12 - No Cached
  • Solar PV (photovoltaic) was first discovered in 1839 by French scientist Edmond Becquerel. Over the next 100 years, there were other discoveries and inventions, including several discoveries by Albert Einstein, who received a Nobel Prize for his theories on the photovoltaic effect in 1921.
  • Solar PV (photovoltaic) was first discovered in 1839 by French scientist Edmond Becquerel. Over the next 100 years, there were other discoveries and inventions, including several discoveries by Albert Einstein, who received a Nobel Prize for his theories on the photovoltaic effect in 1921.
combspat98

How Fuel Cells Work - 1 views

www.fueleconomy.gov/...fcv_pem.shtml

hydrogen convert

shared by combspat98 on 22 Oct 12 - No Cached
    • combspat98
      combspat98 on 22 Oct 12
       
      pictue and descripiton of how fuel cells work
dpurdy

Solar Electricity and how it works - Photovoltaic Systems and Components, Grid-Connected Solar Electric Systems, Off-Grid (Stand Alone) Solar Electric Systems, PV Modules, PV Inverters, PV Chargers, PV Battery, PV Mounting, Small Solar Electric Devices - 0 views

www.solardirect.com/...pvbasics.htm

grid solar transported works how converted

shared by dpurdy on 26 Oct 12 - No Cached
  • A valuable feature of photovoltaic systems is the ability to connect with the existing power grid which allows owners to sell excessive electricity back to the utility with a plan known as (5) Net Metering. At times when you are not using all of the electricity produced by your system, your meter will spin backwards selling the electricity back to the (6) utility power grid at retail rate.
  • (1) Solar Electric or PV modules convert sunlight to electricity. The PV modules generate DC electricity - or direct current - sending it to the inverter. (2) The inverter transforms the DC power into AC electricity for ordinary household needs. (3) Existing electrical panel distributes solar electricity and utility power to (4) loads (appliances). For systems with a battery backup (optional), the inverter also regulates the charge of batteries. The electricity stored in the batteries can be used at night or during blackouts.
    • dpurdy
      dpurdy on 26 Oct 12
       
      Great video showing solar cell (photovoltaic) in action.
  • dpurdy on 26 Oct 12
     
    Solar is not always connected to grid. Sometimes there are batteries, otherwise your system is connected to grid to share excess electricity.
smithcol98

HowStuffWorks "How Solar Cells Work" - 0 views

science.howstuffworks.com/...solar-cell.htm

solar

shared by smithcol98 on 13 Mar 12 - Cached
  • ough light, they seem to work forever. Y
  • ong as there's
    • smithcol98
      smithcol98 on 13 Mar 12
       
      hi max
labrumbra99

A Basic Overview of Fuel Cell Technology - 0 views

americanhistory.si.edu/...basics.htm

fuel cell convert

shared by labrumbra99 on 15 Mar 12 - Cached
  • they generate electricity with very little pollution—much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct, namely water.
  • Scientists and inventors have designed many different types and sizes of fuel cells in the search for greater efficiency, and the technical details of each kind vary
  • in general terms, hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now “ionized,” and carry a positive electrical charge. The negatively charged electrons provide the current through wires to do work. If alternating current (AC) is needed, the DC output of the fuel cell must be routed through a conversion device called an inverter.
  • ...6 more annotations...
  • But in general terms, hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now �ionized,� and carry a positive electrical charge. The negatively charged electrons provide the current through wires to do work. If alternating current (AC) is needed, the DC output of the fuel cell must be routed through a conversion device called an inverter.
  • Every fuel cell also has an electrolyte, which carries electrically charged particles from one electrode to the other, and a catalyst, which speeds the reactions at the electrodes. Hydrogen is the basic fuel, but fuel cells also require oxygen. One great appeal of fuel cells is that they generate electricity with very little pollution–much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct, namely water.
  • A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes.
  • fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode.
  • One detail of terminology:
  • Oxygen enters the fuel cell at the cathode and, in some cell types (like the one illustrated above), it there combines with electrons returning from the electrical circuit and hydrogen ions that have traveled through the electrolyte from the anode. In other cell types the oxygen picks up electrons and then travels through the electrolyte to the anode, where it combines with hydrogen ions. The electrolyte plays a key role. It must permit only the appropriate ions to pass between the anode and cathode. If free electrons or other substances could travel through the electrolyte, they would disrupt the chemical reaction. Whether they combine at anode or cathode, together hydrogen and oxygen form water, which drains from the cell. As long as a fuel cell is supplied with hydrogen and oxygen, it will generate electricity. Even better, since fuel cells create electricity chemically, rather than by combustion, they are not subject to the thermodynamic laws that limit a conventional power plant (see "Carnot Limit" in the glossary). Therefore, fuel cells are more efficient in extracting energy from a fuel. Waste heat from some cells can also be harnessed, boosting system efficiency still further
  • labrumbra99 on 08 Mar 13
     
    "A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes."
  • ricciardellinick on 11 Mar 13
     
    "A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode."
gillinghammic98

How Solar Energy Works | Union of Concerned Scientists - 0 views

www.ucsusa.org/...how-solar-energy-works.html

shared by gillinghammic98 on 15 Mar 12 - Cached
  • By the time it reaches Earth's surface, the energy in sunlight has fallen to about 1,000 watts per square meter at noon on a cloudless day. Averaged over the entire surface of the planet, 24 hours per day for a year, each square meter collects the approximate energy equivalent of almost a barrel of oil each year, or 4.2 kilowatt-hours of energy every day. Deserts, with very dry air and little cloud cover, receive the most sun—more than six kilowatt-hours per day per square meter. Northern climates, such as Boston, get closer to 3.6 kilowatt-hours. Sunlight varies by season as well, with some areas receiving very little sunshine in the winter. Seattle in December, for example, gets only about 0.7 kilowatt-hours per day. It should also be noted that these figures represent the maximum available solar energy that can be captured and used, but solar collectors capture only a portion of this, depending on their efficiency. For example, a one square meter solar electric panel with an efficiency of 15 percent would produce about one kilowatt-hour of electricity per day in Arizona.
krolnik98

how wind energy works - 2 views

www.bwea.com/how.html

wind how converted

shared by krolnik98 on 15 Mar 12 - Cached
    • krolnik98
      krolnik98 on 15 Mar 12
       
      good moving diagram
  • How Does Wind Energy Work? The diagram below shows a simplified version how a wind turbine converts the kinetic energy in the wind to electrical energy around the country. If you can't see the diagram you will need to download flash to see it. The wind blows on the blades and makes them turn. The blades turns a shaft inside the nacelle (the box at the top of the turbine) The shaft goes into a gearbox which increases the rotation speed enough for... The generator, which uses magnetic fields to convert the rotational energy into electrical energy. These are similar to those found in normal power stations. The power output goes to a transformer, which converts the electricity coming out of the generator at around 700 Volts (V) to the right voltage for distribution system, typically 33,000 V. The national grid transmits the power around the country.
  • krolnik98 on 15 Mar 12
     
    cool pics plus good info
dpurdy

A Basic Overview of Fuel Cell Technology - 0 views

americanhistory.si.edu/...basics.htm

hydrogen fuel cell what how

shared by dpurdy on 15 Mar 12 - No Cached
  •   Fuel Cell Basics Through this website we are seeking historical materials relating to fuel cells. We have constructed the site to gather information from people already familiar with the technology–people such as inventors, researchers, manufacturers, electricians, and marketers. This Basics section presents a general overview of fuel cells for casual visitors. What is a fuel cell? How do fuel cells work? Why can’t I go out and buy a fuel cell? Different types of fuel cells.     What is a fuel cell? A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes.
  • in general terms, hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now “ionized,” and carry a positive electrical charge. The negatively charged electrons provide the current through wires to do work. If alternating current (AC) is needed, the DC output of the fuel cell must be routed through a conversion device called an inverter.
  • Oxygen enters the fuel cell at the cathode and, in some cell types (like the one illustrated above), it there combines with electrons returning from the electrical circuit and hydrogen ions that have traveled through the electrolyte from the anode. In other cell types the oxygen picks up electrons and then travels through the electrolyte to the anode, where it combines with hydrogen ions.
sankeyrya00

The Energy Story - Chapter 16: Wind Energy - 2 views

www.energyquest.ca.gov/...chapter16.html

energy windenergy current history sustainable wind

shared by sankeyrya00 on 13 Mar 12 - Cached
    • shannonlan97
      shannonlan97 on 13 Mar 12
       
      inside of turbine picture
  • Farmers have been using wind energy for many years to pump water from wells using windmills like the one on the right
  • When a boat lifts a sail, it is using wind energy to push it through the water. This is one form of work.
  • ...6 more annotations...
  • Wind is also used to turn large grinding stones to grind wheat or corn, just like a water wheel is turned by water power.
  • Wind can be used to do work. The kinetic energy of the wind can be changed into other forms of energy, either mechanical energy or electrical energy
  • n Holland, windmills have been used for centuries to pump water from low-lying areas.
  • Blowing wind spins the blades on a wind turbine – just like a large toy pinwheel.
  • If the wind gets too high, the turbine has a brake that will keep the blades from turning too fast and being damaged.
  • You can use a single smaller wind turbine to power a home or a school. A small turbine makes enough energy for a house.
  • freeberntay99 on 08 Mar 13
     
    "The blades of the turbine are attached to a hub that is mounted on a turning shaft. The shaft goes through a gear transmission box where the turning speed is increased. The transmission is attached to a high speed shaft which turns a generator that makes electricity."
plattjak98

NOVA | How Fuel Cells Work - 0 views

www.pbs.org/...fuel-cell-work.html

hydrogen how

shared by plattjak98 on 13 Mar 12 - No Cached
  • Think of them as big batteries, but ones that only operate when fuel—in this case, pure hydrogen—is supplied to them.
dpurdy

Cost of hydrogen from different sources - 0 views

www.h2carblog.com/?p=461

hydrogen cost

shared by dpurdy on 19 Mar 12 - No Cached
  • Estimated cost of hydrogen per kilogram in a variety of scenarios With all of this in mind, here are the cost estimates per kilogram (which each include $1.25 for taxes): Hydrogen from natural gas (produced via steam reforming at fueling station) $4 – $5 per kilogram of hydrogen Hydrogen from natural gas (produced via steam reforming off-site and delivered by truck) $6 – $8 per kilogram of hydrogen Hydrogen from wind (via electrolysis) $8 – $10 per kilogram of hydrogen Hydrogen from nuclear (via electrolysis) $7.50 – $9.50 per kilogram of hydrogen Hydrogen from nuclear (via thermochemical cycles – assuming the technology works on a large scale) $6.50 – $8.50 per kilogram of hydrogen Hydrogen from solar (via electrolysis) $10 – $12 per kilogram of hydrogen Hydrogen from solar (via thermochemical cycles – assuming the technology works on a large scale) $7.50 – $9.50 per kilogram of hydrogen As mentioned above, a cost of hydrogen of $4 to $12 per kilogram is equivalent to gasoline at $1.60 to $4.80 per gallon.
dpurdy

HowStuffWorks "How the Hydrogen Economy Works" - 0 views

auto.howstuffworks.com/...hydrogen-economy2.htm

pollution location sustainable co2

shared by dpurdy on 03 Nov 11 - No Cached
  • 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.
  • anonymous on 28 Sep 13
     
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dpurdy

Energy Resources: Wave power - 1 views

home.clara.net/...wave.htm

wave pollution sustainable

shared by dpurdy on 03 Nov 11 - Cached
  • Ocean waves are caused by the wind as it blows across the sea. Waves are a powerful source of energy.
  • How it works There are several methods of getting energy from waves. One of them works like a swimming pool wave machine in reverse. At a swimming pool, air is blown in and out of a chamber beside the pool, which makes the water outside bob up and down, causing waves.   At a wave power station, the waves arriving cause the water in the chamber to rise and fall, which means that air is forced in and out of the hole in the top of the chamber. We place a turbine in this hole, which is turned by the air rushing in and out. The turbine turns a generator.
  • Once you've built a wave power station, the energy is free, needs no fuel and produces no waste or pollution.
  • ...4 more annotations...
  • Not expensive to operate and maintain.
  • Needs a suitable site, where waves are consistently strong.
  • Some designs are noisy. But then again, so are waves, so any noise is unlikely to be a problem.
  • Is it renewable? Wave power is renewable.
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