Hot answers tagged renewable-energy
8
Yes, the claims in the video are totally absurd from the viewpoint of science. It's enough to listen for roughly 70 seconds to be sure that the narrator doesn't have the slightest clue about physics and the remaining 302 seconds make this fact even more self-evident. I won't try to answer the question whether the authors of the video realize that what they ...
6
To essentially quote http://en.wikipedia.org/wiki/Tide:
Energy of the Earth is not conserved while energy of the Earth-Moon system must exist. Energy from bodies of water are diminished (by about 3.75 TeraWatts) where about 98% of this energy loss is due to marine tidal movement.
Because energy is lost in the water, this imposes a torque on the Earth ...
6
First, let's do some back-of-the-envelope calculations. The word for the average amount of Solar energy reaching the Earth's surface over the course of a year is "insolation." According to this page, insolation in populated areas ranges from $2.27\,\mathrm{kWh/day/m^2}$ in Norway to $5.26\,\mathrm{kWh/day/m^2}$ in Miami, Florida. In slightly different units ...
5
As I understand it, there are two versions of this idea. The first is kind of interesting and might work - the idea is that you heat the air at the bottom using a power station, and allow the vortex to carry the air into the upper troposphere. The vortex acts like a chimney, drawing the hot air out of the unit, causing a pressure difference that allows you ...
5
Storing electricity as electricity is currently possible only in capacitors. A lot of fuss is made about the potential of super-capacitors and ultra-capacitors to scale up, but little has happened yet at the grid level.
Almost everything else involves converting electricity to a different kind of energy; and then converting it back to electricity when ...
5
Typically, yes, the water does need to be pumped up.
Because if it released energy by rising, it would already have risen to the surface.
OTEC depends on a high-enough temperature difference between the lower-depth water intake and the higher-depth one, for that temperature difference to do enough work to provide some surplus power, in addition to the ...
4
Yes, many things rob Earth's angular momentum and slow it down.
For example, when a rocket lands on Earth, it gains/loses speed due to the Earth's rotation. Other than that, when a rocket leaves Earth, they use the fact that the Earth rotates in order to gain kinetic energy from the Earth's rotation. In other words, the rocket robs the Earth's energy.
NASA ...
4
What you propose is a version of concentrated PV.
Concentrated PV has been in development for some time.
The big issue with PV, is lifetime cost per unit energy. There are no other constraints really - there are plenty of alternative commercial panels that material shortages aren't an issue; we know we can manage their exogenously variable power ...
3
Yes, you would need a lot of wind turbines to have a significant, noticeable effect on the weather. There are three potential impacts:
Wind turbines will change the pattern of turbulence downwind from them.
Wind turbines will take some energy out of the wind
Wind turbines will typically displace thermal plant generation, which means that less heat and less ...
3
There are several ways to design the circuit.
If it's a Smart system, then when there's surplus power, additional devices will get turned on, to use it: dishwashers, washing machines, or immersion heaters in hot-water storage tanks. If there's still surplus after that, then it's as below.
If it's grid-connected, with an inverter, then it's usually designed ...
3
This site covers four current modes of electricity storage:
1.Pumping water from low to high elevations for future hydroelectric use as needed.
2.Melting salt at solar farms to several hundred degrees and storage in insulated tanks, for future use.
3.Compressed air energy storage by wind farms into underground geologic formations.
4.Utilizing "flow ...
2
Well, as has been mentioned, it is really an issue of your consumption rate. This physicist here has already made the transition to solar power and storage, complete with detailed description and numbers. He's a bit evangelical, but several of his posts are quite interesting. But yes, with an emphasis on efficient appliances and sparing use, one can have ...
2
Hmm, I think it would depend on the panel circuit. If the panel is not connected, for example, the charge potential would still be created at the leads, but since it's not being drained into a storage device (or otherwise used), the solar medium would saturate at some measurable voltage boundary. Whether it turns to heat at that point depends on whether ...
2
I'll answer the current version of the answer and a bit of a previous.
The math is extremely basic. If the power production grows 2.3% a year and the initial power production is $2 \cdot 10^{13} \, \text W$ then in 1400 years your energy production would be:
$$P_{1400} = 1.023^{1400} \cdot 2 \cdot 10^{13} \approx 0.13 \cdot 10^{28} \, \text{W}$$
Now, ...
2
To harness the energy of the Earth's rotation, you need something with different angular velocity (just like harnessing thermal energy requires two things at different temperature). Everything on Earth is rotating with the same speed, and so has the same angular velocity; the closest thing with a different angular velocity is the Moon.
This is in fact what ...
1
There are a few important points to make before I attempt an answer. The first is just a point about terminology: you have to be careful to distinguish between energy and (angular) momentum. They are not the same thing - they have different units - and so it doesn't strictly make sense to talk about "draining energy from Earth's angular momentum", since it's ...
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