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Name: Sim
Status: Student
Grade: 6=8
Location: N/A
Country: United States
Date: Winter 2009-2010


Question:
Can we use snow to produce energy/electricity?



Replies:
Sim,

The short answer is no, not really. There is not much useful energy that can be extracted from snow.

Consider the principle of conservation of energy, which states that energy cannot be created, it is just converted from one state to another. What this means is that energy is not really 'created', it is actually just captured from a high-energy source. The amount of energy you can use/capture depends on converting something from a higher-energy state to a lower-energy state.

A simple example is a spring. When the spring is compressed, it is at a high-energy state. When you release it, it can transfer that energy to something else (for example, to launch a ball into the air). But afterward, the expanded spring is in a low-energy state. This is an example of mechanical energy. You can also capture energy from high-temperature materials - like steam. Steam is an example of thermal energy.

Getting more into chemistry, in order to extract usable energy from a material, you have to convert a high-energy material to a lower-energy state. For example, in a combustion engine, gasoline is converted to carbon dioxide and water. This is an example of chemical energy. There is a lot of energy stored in the chemical bonds in gasoline, and much less energy stored in the chemical bonds of carbon dioxide and water. The energy that we can capture is in the difference between the high energy state and the low energy state.

In the case of snow, there is not much of a lower-energy state that snow can move toward. There is not a lot of energy stored in the bonds of water, and it is at a low temperature, and there is not much mechanical work to capture from it.

Perhaps the best example I can think of to use snow for energy might be a little more indirect than you were thinking. The idea is to use snow that is on a mountain. Because the snow on a mountain is at high elevation, it has "potential energy" due to its height. When the snow melts in spring, the water flows down the mountain, and that water flow can be used to generate electricity (hydroelectric power). However, I do not know of a way of using snow directly (as a material) to generate power.

Hope this helps,
Burr Zimmerman


Sim

I have not heard of any way to produce energy/electricity from snow. Maybe you will find a way in your career.

Sincere regards,
Mike Stewart


Unfortunately, I do not see a way to do this that will be energy efficient. Here is why:

In order to extract energy from snow (assume @ 0 C. because it does not affect the outcome) you must be able to deliver heat from 0 C. to some lower temperature). That is a law of nature called the Second Law of Thermodynamics. So you need a heat sink to absorb the heat from the snow. I do not see any candidates. But things get even more messy. The maximum amount of "work", i.e. the useful energy for driving a machine or some such a process, is limited. The maximum efficiency is given by a simple formula: (work) / (Q hot) = (T hot - Tcold) / T hot, where T hot and T cold are the higher and lower temperatures (in kelvins) and Q hot is the heat extracted from the flow of energy from the high temperature to the low temperature. So even if you can find a useful heat "sink", the amount of "work" that can be extracted is not very high. That is why furnaces are run at high temperatures.

Vince Calder



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