Energy sources that do not rely on the consumption of an exhaustible fuel. Tidal, geothermal, and the direct and indirect solar energies (direct: photovoltaics, CSP, solar thermal; indirect: wind, wave, biomass) are renewable energy.

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2
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1answer
360 views

Solar energy and optical fiber

I'm not really good at science or physics, just wanted to ask about the idea (doesn't have an opportunity to test this). Will this scheme work and what can be its efficiency?(The goal is to make ...
7
votes
4answers
705 views

Optimal speed for the water wheel

The hydroelectricity plants extract the potential energy of highly deployed massive object (water) as it falls down. Without turbine, all that energy would be converted into speed (kinetic energy) at ...
1
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2answers
351 views

Do bifacial solar panels operate at lower temperature than normal solar panels?

Bifacial solar panels have a glass backplane instead of the usual aluminum and are designed to absorb and convert to electricity light incident on either face. Many manufacturers claim that their ...
0
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0answers
20 views

Is there a temperature drop at the rotor plane of a wind turbine?

A wind turbine rotor produces power from the torque generated by the rotor blades. This torque arises from forces on blade elements which in turn are the consequence of pressure differences on each ...
1
vote
1answer
695 views

Can capillary forces be used to make hydro electricity?

Could a device with very thin columns of glass or something that attracts water more be used to pull water up and then release it to drive generator and perhaps add vacuum. I have been wondering ...
3
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3answers
2k views

Would a thinner atmosphere (such as high altitude) yield better solar panel energy generation?

I am curious. If you were to put a solar panel up in high altitude or on the surface of the moon, both of which have much less atmosphere to reflect/refract light, would that solar panel produce more ...
1
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0answers
43 views

Wind turbine design question [closed]

I am planning to design a wind turbine that is has rotor blade radius of 0.915m and is connected to a generator. The generators specifications are, it is an ac generator with 5000 coil turnings and a ...
11
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2answers
616 views

Energy from man-made tornadoes

Peter Thiel just paid $300,000 to Canadian inventor Louis Michaud who is working to construct useful "man-made tornadoes" or "atmospheric vortex engines" which could be components of future power ...
0
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0answers
32 views

How to calculate theoretical power generated depending on temperature

I know the current technology of gas turbine and how they use extremely hot gases to generate power. However, if there was no combustion and compressor system associated with the gas turbine, how can ...
1
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0answers
23 views

Measurements of the pressure drop across wind turbines?

Mathematical analyses of wind turbines show that a discontinuous pressure drop happens at the rotor plane. I am looking for measurements of this effect, but I could not find any. Do you know any (...
0
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1answer
271 views

Can we make a “Gravity Mill” based on principle(s) of Newton's cradle?

DISCLAIMER: Newbie/Wannabe Physicist. What's to stop us from making a "Gravity Mill" which is a bar/rod attached with weights on both ends and pivoted at the ...
0
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0answers
22 views

how to calculate Cp of wind turbine

I am having trouble calculating C$_p$ of my wind turbine The radius of my rotor blade is 4.5 inches and it's rotation per second is 10 (10 rotations per second). So I found my tip speed of blade ...
1
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0answers
24 views

solar energy on a specific location

How to find the amount of solar wattage in any specific place on earh in a monthly manner? by solar wattage I mean the energy recieved from the sun in a squared meters.
0
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1answer
50 views

How to calculate power necessary generated from wind turbine to run a motor

I was making a small/cheap wind turbine, and I am stuck on how to calculate the power needed (speed of wind) to run a brushed motor (since I figured that would be the easiest to run with rotor blades ...
2
votes
3answers
186 views

Could sound be considered a kind of renewable energy? [closed]

Is sound energy useful as a source for generating electricity? If so, could it be a renewable resource?
0
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3answers
355 views

Is possible to generate energy from gravity?

When the wind goes through the vanes of an wind turbine, that energy is harnessed to generate electricity. When the water goes through the water turbines, that energy is harnessed to generate ...
1
vote
8answers
467 views

Why not use our own light production to produce new energy instead of wasting it?

Why don't we use our own light production at night (I mean home, buildings, streets,..., lighting) to charge photovoltaic panels instead of wasting it?
0
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2answers
57 views

which is efficient on solar electricity by photo voltaic or thermal

As we know solar energy used to generate electricity in two major ways: photovoltaic and thermal energy. The most small applications or personal use are mostly using solar cells. But when it comes to ...
2
votes
2answers
2k views

In solar cells, do photons break apart electron-hole pairs, or create them?

Some sources say that when a photon hits the PV cell, it breaks apart electron-hole pairs. Other sources say that photons create electron-hole pairs. Can anyone explain which one is right? I've read ...
-1
votes
1answer
38 views

is it viable to pump water with wind before turning it into electricity? [closed]

If one was to place many [short] turbines along a windy bridge, a levee or a windy road could one remedy the losses from many small generators, low voltage and large distances by pumping water in ...
0
votes
1answer
25 views

What parameters decide the maximum concentration achieved by a fresnel lens?

Fresnel lens can be used for concentrating sunlight for Photovoltaic. What parameters of the lens decide the maximum concentration that can be achieved using the lens.
0
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0answers
11 views

What is the distribution of a battery transmission?

I have an energy-harvesting battery attached to a node, transmitting data over Rayleigh flat fading channels. Energy in the battery is used, and simultaneously energy is harvested and stored. I want ...
1
vote
1answer
62 views

What mechanism can we use to convert waves energy?

In term of renewable energy, can we use waves as another energy that can be stored and used instead of solar, wind and etc ? What I mean here is not sea waves but another kind of waves such as radio ...
0
votes
1answer
19 views

Attracting atmospheric positive ions to carbon nano tubes for collection

Can nano magnets built into carbon nano tubes be used to attract moving positive ions from atmosphere to increase the resultant positively charged collecting mass?
0
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0answers
26 views

Karman Vortex Street phenomena to turn mechanical energy into electric energy at nano to mm scale?

How can one determine mathematically if it is practical to use the Karman Vortex Street phenomena at a nano scale or mm level to harness the wind's mechanical energy via a carbon nano tubular ...
10
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4answers
7k views

Where does the electricity, generated by a solar panel, go if you don't use the electricity?

I'm sorry if this question is too trivial for this Q&A forum. I am a layman when it comes to physics (though I did cover the high-school physics courses). I was wondering what happens to the ...
1
vote
3answers
3k views

Can energy be extracted from clouds?

Can cloud charge imbalance be used as an energy source? First off quite some energy must be present in clouds: a lightning path is quite long, and electrical breakdown of air requires about 1MV/m. ...
38
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2answers
3k views

Wind generators - why so few blades?

Why commercial wind generators usually have just 2-3 blades? Having more blades would allow to increase power OR decrease diameter. Decreased diameter would also reduce stress due to different wind ...
5
votes
4answers
3k views

Why do solar cells have a window layer on top of the absorber layer and not below it?

In solar cells there is a p-n junction. P-type semiconductor (for example CdTe) is often absorber layer because of its carrier lifetime and mobilities. In case of CdS/CdTe,* CdS is n-type window layer ...
4
votes
2answers
72k views

Is Keshe's technology for real?

http://www.youtube.com/watch?v=UrN99RELqwo (Video Title: "Keshe Foundation Promo Intro Video (english with multiple subtitles) === PLEASE SHARE ===") In this video they claim that they can create ...
1
vote
1answer
749 views

Is Ronald Ace's “solar trap” patent plausible?

This newspaper article and a few others from last year discussed a patent by independent US inventor Ronald Ace. It's about a kind of absorber for solar thermal energy systems, and it's supposed to ...
0
votes
3answers
240 views

Lightning Power?

What is the power source of a lightning? It doesn't consume fuel, nor an atomic fission/fusion, but it discharges a large amount of energy. Is it feasible to create an artificial lightning using the ...
2
votes
2answers
807 views

Do wind turbines convert the kinetic energy of air?

It is often said that wind turbines convert the kinetic energy of the wind into electricity. But in respect to horizontal wind turbines with airfoil shaped blades this is imho not the case. Wind ...
1
vote
1answer
54 views

How is the kinetic energy of the wind transferred onto a lift based wind turbine?

The rotor blades of a lift based wind turbine are shaped like airfoils, so the wind flowing around them creates a lift force which in turn moves them around. From a thermodynamic viewpoint and like ...
3
votes
4answers
10k views

What happens if a wind mill rotates in opposite direction?

Suppose if a windmill is made torotate in clockwise direction and due to air flow if it rotates in anti clockwise direction then does it produce electricity?
2
votes
2answers
222 views

How absorption coefficient determines which material is used to make solar cells?

Does the knowledge of the material absorption coefficients aids engineers in determining which material to use in their solar cell designs? If yes, how?
14
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2answers
4k views
1
vote
0answers
46 views

How big is the power loss of a downwind wind turbine due to turbulence created by an upwind turbine?

When a horizontal axis wind turbine is placed downwind of another horizontal axis wind turbine (distance between the two is minimal), then the downwind wind turbine has a lower power output because of ...
5
votes
2answers
80 views

Potential energy of Hydroelectric plant before the dam was built

So the energy potential of a Hydroelectric dam is the difference between the head and base. Before the dam was built where does all that energy go? I can understand that for a long valley that is ...
9
votes
1answer
252 views

Will the upcoming solar eclipse stress the European electrical grid?

From an article in the Financial Times today, about a solar eclipse on March 20th, 2015: An eclipse of the sun next month could disrupt Europe’s power supplies because so many countries now use ...
13
votes
6answers
16k views

Are Fresnel lenses widely used for solar electricity? If not, why not?

I was just wondering why Fresnel Lenses are not widely used in the production of solar electricity. Their use there would mean that you could produce heat within a fraction of a second, up to a few ...
0
votes
1answer
69 views

Electricity from effervescence, is it possible?

I've had this idea for quite some time (after having a cold and seeing Tabcin sparkling tablets), is there the possibility to generate electricity from effervescence? I envisioned something like the ...
0
votes
6answers
12k views

Is it possible to generate electricity using a water tower?

Is it possible to build a water tower that will provide enough pressure to run an electricity generator? A water pump can be used to send water up to the tower. The water pump can be powered by solar ...
12
votes
2answers
6k views

Where does electricity go from a solar panel that is not plugged in to anything?

I found a similar question here on this site, but my question is slightly different. If a solar panel is exposed to sunlight but is not plugged in to anything--dc load, inverter, etc--where does that ...
6
votes
1answer
1k views

Would the ionic wind power fence actually work?

Described here and in the references (patent, patent), the idea is to use a large fence as a grid electrode. Spray water droplets near a high voltage to charge them, and then the wind blows them away,...
2
votes
2answers
1k views

Rare earth minerals in solarcell production

When I was looking at photovoltaic solar cell production I saw that there was some difficulty with rare earth minerals used in the production but i can't find which rare earth minerals. I have tried ...
0
votes
2answers
55 views

Is the amount of hydro-electricity harvested, proportional to the number of turbines? [closed]

I've looked on this site and people have said that it wouldn't make more energy that it would cost to have water turbines on a water tower. But if it only takes say three pumps (I don't know what it ...
0
votes
2answers
67 views

Question on power

A wind turbine produces a power $P$ when the wind speed is $v$. Assuming that the efficiency of the turbine is constant, the best estimate for the power produced when the wind speed becomes $2v$ is (...
0
votes
1answer
155 views

Do you think it’s possible to make a power plant of the described kind?

We are working on a science project and try to engineer a power plant of a new kind. It is called Air HES (air hydroelectric station). The idea is described on our website. Do you think it is ...
3
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3answers
3k views

How to calculate the temperature of a receiving point from concentrated solar power?

I'm exploring a DIY project about solar power and have found very few resources that can explain, in a not too simple but not too advanced way, how to go about calculating important values in solar ...