Transformations of Energy in Wind Power

[fatcats]

Homework Statement

Choose one form of electrical generation and in point form outline the process through which electricity is generated and the energy transformations that occur.

Homework Equations

NA

The Attempt at a Solution

Hi, I am done my work and I used two reliable sources. This question is worth five marks. What I would like to know is if my answer makes sense/if I am correct and if I am missing anything. Would really appreciate it.

– Winds are caused by the uneven heating of the atmosphere by the sun combined with the irregularities of the earth’s surface and the rotation of the earth.- Moving air pushes against the blades of the turbine making them rotate. Some of the kinetic energy of the wind is transformed into the mechanical (rotational kinetic) energy of the spinning blades.

- Some energy is lost; it is converted into thermal energy (due to friction) and sound energy (the blades are noisy).

- The wind still has some kinetic energy as it flows through the turbine.

- The blades are connected to a rotor, which is connected to the main shaft. The shaft spins a generator.

- The shafts and gears inside the gear box transfer the mechanical energy of the turbine to the generator. The gears make the drive shaft to the generator spin faster than the shaft connected to the blade hub.

- The mechanical energy keeps moving through the different parts of the turbine until it hits the generator. The energy remains in the mechanical form. Along the way some is converted into thermal energy.

- The generator can convert this mechanical power into electricity.- Wind turbines do not produce electricity all the time. Wind may be available as much as 70% of the time, but it is often not strong enough to operate the turbine at full capacity. Over the course of a year, only 30% energy of a constant strong wind’s potential energy will be generated. A good site might have a 35% capacity factor.

 

[berkeman]

Homework Statement

Choose one form of electrical generation and in point form outline the process through which electricity is generated and the energy transformations that occur.

Homework Equations

NA

The Attempt at a Solution

Hi, I am done my work and I used two reliable sources. This question is worth five marks. What I would like to know is if my answer makes sense/if I am correct and if I am missing anything. Would really appreciate it.

– Winds are caused by the uneven heating of the atmosphere by the sun combined with the irregularities of the earth’s surface and the rotation of the earth.- Moving air pushes against the blades of the turbine making them rotate. Some of the kinetic energy of the wind is transformed into the mechanical (rotational kinetic) energy of the spinning blades.

- Some energy is lost; it is converted into thermal energy (due to friction) and sound energy (the blades are noisy).

- The wind still has some kinetic energy as it flows through the turbine.

- The blades are connected to a rotor, which is connected to the main shaft. The shaft spins a generator.

- The shafts and gears inside the gear box transfer the mechanical energy of the turbine to the generator. The gears make the drive shaft to the generator spin faster than the shaft connected to the blade hub.

- The mechanical energy keeps moving through the different parts of the turbine until it hits the generator. The energy remains in the mechanical form. Along the way some is converted into thermal energy.

- The generator can convert this mechanical power into electricity.- Wind turbines do not produce electricity all the time. Wind may be available as much as 70% of the time, but it is often not strong enough to operate the turbine at full capacity. Over the course of a year, only 30% energy of a constant strong wind’s potential energy will be generated. A good site might have a 35% capacity factor.

Good work!

I think I'd like to see a little bit more about how the sun's thermal energy input to the Earth actually creates wind, but otherwise, you have don't a good job. I can tell you've been doing a lot of reading ans summarizing to come up with this answer.

 

[haruspex]

Winds are caused by the uneven heating of the atmosphere

I suspect you have in mind uneven heating of the Earth's surface. In fact, winds would still be generated even if the surface heating were perfectly even. What matters is that the air gets most of its heat from the warmed surface, making it too hot at the bottom to be stable and initiating convection.

Over the course of a year, only 30% energy of a constant strong wind’s potential energy will be generated. A good site might have a 35% capacity factor.

You might be confusing two things here.
There is a theoretical limit to the fraction of the wind's energy that can be extracted. See https://en.wikipedia.org/wiki/Betz's_law.
Separately from that, a given turbine has a maximum possible power output, no matter how good the wind. This is its nameplate capacity, e.g. "a 3MW turbine". Its actual long term average output will be some fraction of that, known as its capacity factor. Advancing technology affects this in two ways: at the best sites, capacity factors can now hit 50% even for onshore- offshore even better (http://reneweconomy.com.au/wind-turbine-net-capacity-factor-is-50-the-new-normal-50910/), but at the same time it means poorer sites can be viable and might be preferred for other reasons, so the average capacity factors do not increase so much.

 

[fatcats]

Thank you for your feedback !