1. AIRBORNE WIND TURBINES Sean Metcalf Special Thanks: Sam Musa, Joshua Owens, and Greg Hutcheson
OBJECTIVE:
Determine the feasibility of using Airborne Wind Turbines (AWT) as an alternative way of utilizing wind energy to reduce the use of non-renewable energy sources.

2. BACKGROUND INFO:
Figure 1: Description of how the AWT operates
Makani Power, Joby Energy, KiteFarms and KiteGen have developed working prototypes and designs for high altitude AWTs
Desired to produce more and consistent energy more cost effective than conventional solar and wind power
Developed fixed-wing AWT, operational at altitudes of 250 to 600 meters.
Makani Power tested prototype capable of 30 kW production.

3. RESEARCH & ANALYSIS:
Research feasibility of utilizing AWT’s as an alternative source to harvest wind energy in the effort to reduce the use of non- renewable energy sources
Conduct thermodynamic analysis and compare maximum power output for 30 kW AWT and a 30 kW conventional wind turbine
Figure 2: Makani M30 AWT technical specifications

4. COMPARISON: AWT offshore wind farm applications
AWT’s perform better at low wind speeds than conventional wind turbines
Can produce about twice the power of a traditional wind turbine the same size
Wind power represents %32 of all new electric capacity additions in the U.S. for 2010
Accounts for $14 billion in new investment
U.S. wind power capacity reached 50,000 MW, enough electricity to power 13 million homes annually
Figure 3: Wind energy production comparison (wind power information and figure used from )

5. SAFETY & IMPACT:
Operates below altitude of commercial flights and above the height of migratory birds
90% less material than a conventional turbine
Can operate in hurricane conditions with winds in excess of 50 m/s with gusts reaching 80 m/s
During extreme weather, it can land autonomously until conditions normalize
Figure 4: Comparison of area and height between conventional turbines and the AWT

6. ANALYSIS:
Thermodynamic derivation for rate of work or power output for a wind turbine using assumptions:
Assumptions:
Reversible process
Control volume
Heat Transfer and Potential Energy are negligible
Steady-State
Constant wind velocity
Note: Equations uses constant for Betz ‘ Law, which limits the theoretical max. power efficiency for any turbine design to be %59.
Observations:
It is observed that the energy available in the wind for a turbine is only in the form of kinetic energy. The total power that can be derived from wind using a wind turbine is:

7. CONCLUSION:
AWT system is feasible because it yields more energy more often because it taps into a more consistent and powerful wind at a higher altitude
Doesn’t harvest most of the energy available to it, but it harvests what would otherwise remain untouched
Promising solution for harvesting offshore and land renewable wind energy with low initial investment
Mechanical, electrical, and computer automation systems maintenance for AWT’s would create more jobs
Table 1: Using the above Power equation the following table shows the power yield for a 30 kW conventional turbine (model # FD 10-30/12 manufactured by Wind Resource Energy) and a 30kW AWT (model M30 Manufactured by Makani).
Type
Horizontal Shaft Wind Turbine
Airborne Wind Turbine
Make/Model
WER FD 10-30/12 (30kW)
Makani M30 (30kW)
Sky Area
78.5m2 (5m radius)
1809m2 (8meter wing span)
wind Speed (m/s)
Available power (W)
Actual output (w)
% total Energy 7
9695.4
5300
54.7%
15000
0.07% 10
1800
6.37%
30000
4.6% 13
34000
2.1% 16
29000
25.0%
1.1%

8. References: http://www.makanipower.com/how-does-it-work/
fly-a-kite/
manufacturing-surges-supporting-jobs-and