# Wind Turbines Take-Aways

FB: I was surprised at how little power wind can generate. It is incredible how inefficient our systems are. Not only that but even commercial wind power must receive huge nudges in order to build turbines.

It is interesting to see the reality of this alternative energy source.

KM: Working with Balsa Wood and Cardboard got me thinking about what goes on in GE’s wind lab, and what kind of materials and methods that they use to design new turbines.  But, seeing our quirky designs actually function (though with very low efficiency and power) was very cool!  But the scale needed to actually create useable power is inedible!

SM: It was really upsetting to lose so much efficiency during this lab. I’m quite confident that the powered fans we were using to simulate wind were consuming far more then the 34 mW that we were able to produce, at a maximum, from our wind turbines. It goes to show that capturing the energy of wind has plenty of room to grow. Alternatively, this could tell us that we should cut our losses and start investing more in alternative sources of energy, specifically ones that require less capital needs.

AL: I was quite taken away by how inefficient our models were.  It made me realize how much of a challenge it is to find alternative energy sources without losing money or efficiency.  However, I found the computation portion of this lab quite interesting. It was really cool to see the monthly electricity demand of our own state and try to interpret it.

CD: I was really glad that I got to learn some Excel functions that I hadn’t known before. This will certainly make calculating a big chunk of data easier in the future. For the second half of the lab, we tried to make wind turbines. After calculating the efficiency for our wind turbine, I was really surprised to see how low the number was (less than 1%). This makes me rethink about how effective wind is as a source of power, since you will need to build a gigantic wind turbine for a certain energy demand and it will need to be built somewhere constantly windy (which is quite hard to find to find considering how our average wind on Keyes’ roof is around 4-6 m/s).

GB: I really enjoyed constructing the wind turbines because it made me realize how much calculation and precision must go in to creating the most effective wind turbines. There are so many factors at play which make constructing an efficient turbine very difficult. George and I created this cool whale-fin inspired design from what George had read on the internet, I was impressed at his innovation! In the second part of the lab, I was shocked when calculating how the wind energy compared to burning a lump of coal. Similar to other labs it set in stone the difficulty of finding an effective alternative energy that is as versatile, affordable, and efficient as the sources we use today.

DB: Getting the hands-on experience of accessing different blade geometries, putting the turbines together, and testing them put wind power into perspective for me.  There are a lot of technologies that seem to sound great in theory, but need to be applied logically in reality to make a real difference to society.

SJ: This was a really special opportunity to experiment with wind power in a hands-on way. Not knowing much about the physics of wind power prior to this, I was shocked by how inefficient we calculated our wind turbine to be (0.65%); it didn’t generate enough power to run a small coffee cup heater. This lab gave me great insight into just how many factors may influence turbine efficiency, and how the interactions between machines, weather, and energy economics all play into the costs and benefits of wind power.

GV: One of the things that I was particularly interested by during this lab was the tradeoff between rotational speed and torque, the smaller the blades of the turbine the faster it would spin due to lower moments of inertia, but the longer the blades the more torque was generated from them rotating. I also through that it was really impressive to see how excel is capable of handling such huge amounts of data and making a histogram with it without too much trouble.

AB: Before coming to the lab section, I did some research on the ideal blade design. There were many different suggestions, and I kept them in the back of my head, while building some designs. In the end we calculated the efficiency of our demo. The results were surprisingly very bad. We had an overall efficiency of .17%. After further calculation, only when do you have blade sizes of 100 m do these wind turbines become efficient. In the second part of the lab, we looked at the data from the top of the Keyes roof. Then we calculated average wind speed and temperature. We then calculated how efficient a 20 m turbine would be if it was installed on top of the Keyes roof.

JB: I did not know that wind turbines were that inefficient before this, although since the wind is a renewable resource I don’t think it matters as much as the efficiency in a fossil fuel engine or any other sort of power generation source that uses nonrenewable power. I also learned that the more blades a wind turbine has the faster it will start up but the fewer blades it has the faster it will spin once started. It was also interesting to work through the logic of electricity’s positive price elasticity over time.

ER: Although it was fun to tinker with different designs and angles for these tiny turbines, it was a little disheartening how little energy the systems actually generated. I’ve never looked so closely at a turbine from the perspective of an engineer, only as an environmentalist, and it’s easy to see how difficult it could be to install this equipment on a large scale.

DZ: This week’s lab is quite complex. We built some simple wind power generators and measured the efficiency of them, and then calculated the potential wind energy on campus and the energy demand with given data. I find something interesting: first, our wind power generator has a very low efficiency. I thought I made mistakes in calculation and checked again and again. It seems that building a high efficiency generator is not an easy work. I am also impressed by the large amount of potential wind energy. The generator in question C can produce more than 3000 kwh electricity each year. However, I notice that wind power is quite unstable. It is not as easy to use as solar energy.

EL: I think what I found most interesting with the wind lab was that if you are taking energy out of the wind you must be cooling the wind.