This award is given to the team that best exemplifies the mission of the institute: “transforming scientists into leaders who can take risks and develop technical, social and economic innovations.” Winning MEng students are: Erica McClinton, Shahal Neema, Ali Elashri and Austin Campbell.

Executive Summary

The goal for this project is to determine a solution for extracting wind  power in a way that is less intrusive to wildlife  and less visually and audibly disturbing to nearby residents, issues that are typically not addressed in traditional wind turbines. Through our  competitive research and  literature survey, we found that  a small scale, vertical  axis, Savonius type wind  turbine can be a potential solution to harvesting wind  energy in communities like Marin  County. Our  work  was dedicated to enhancing this design with  wildlife  safety  features, improving its aesthetics, and  optimizing performance through an iterative process  involving computational fluid dynamics simulations and the design-by-morphing methodology.

While Marin County is planning to transition to 100% renewable energy sources  by the the year 2025, many community members have expressed their concerns that wind turbines would pose a threat to wildlife,  negatively impact  the visual landscape, and be audibly disruptive. The human-centered design process  allowed us to identify these concerns and  develop a solution to harvesting wind  in Marin.  The small size of our design naturally lessens  the visual  impact  it would have  on the landscape.

Image from: “Redesigning wind power“, Berkeley Engineer,  6/1/2018.

As for wildlife  safety,  traditional wind turbines have  been  criticized for the many  bird  fatalities associated with  them;  our  small  scale turbine has the advantage of operating at heights that  are lower  than  the flight paths  of birds of prey,  thus  reducing the possibilities of collisions  with them.  Also, the concentrator feature on the design shields the blades  from birds approaching in the direction of the wind  and  allows  the birds  to better  perceive the turbine as a stationary object that they can avoid,  as opposed to the blurred blades  of a traditional design that can be very confusing for the birds.  Lastly, unlike traditional turbines which are very loud due to their high tip speed  ratios, our drag based  design has much  lower  tip speed  ratios  and  is consequently much quieter.  However, the regulations present technical  obstacles  for the design of a wind  turbine; the main  problem being  the height. The 40 foot height  restriction for wind  turbines in Marin  subjects  the turbine to much  lower  wind  speeds and more  turbulent winds, which  greatly reduces the turbine’s available power. Since our design is drag-based, it is better able to extract the energy from the low speed, turbulent winds than  the lift-based traditional turbines are.

Project flow, starting with the identification of needs and finishing with a morphed turbine design

The other  aspect  of this project  involved the optimization of an existing  design, the California Energy  and Power  (CE&P) turbine. New  designs were generated using  a process  called design-by-morphing: a computational  method that  allows  us to combine any  number of shapes to produce a final combined geometry. Our team focused on generating new designs for the concentrator that were then tested for performance using computational fluid dynamics. Five new  concentrator shapes were generated and  then  simulated with  a 24 mph wind  speed  and two different rotational speeds, 4RPM and 40RPM, along  with  the original design. At 4RPM, which is the operating condition recommended by CE&P, the original design performed the best with a power output of 2.82 kW. When  the operating speed  was  increased to 40 RPM, all five new  geometries performed much  better  than  the original, with  the best design producing 8.85 kW while  the original produced only 6.90 kW. However, these results have some uncertainties from the lack of better  computational equipment.

Through many  interviews with  community members and  field experts, as well as attending community events,  we were able to gain a much better understanding of what  it takes to site wind  power in Marin County. Eventually, the goal is to site a small  scale prototype of this design in Marin  to hopefully increase  the acceptance of wind  turbines in the area and encourage more wind  turbines to be sited in the region.  While exploring California Energy  and Power ’s turbine, our team was able to find improvements in bird safety, aesthetics, and performance. The initial  tests show  power improvements of about  250% by operating at 40 RPM instead of 4 RPM, suggesting that greater power output is possible  at higher operating speeds. Future teams  could benefit from  exploring more  designs and  optimizing the operational speeds and  tip speed  ratios.   The wildlife  and structural implications of increasing the operational speed  are something that should also be investigated.

Download Wind Power Final Report.

Wind Power Team (left to right):  Bruce Webster, (industry co-sponsor), Judd Howell (Ecologist), Tom Flynn (industry sponsor), Erica McClinton (MEng student), Shahal Neema (MEng Student), Alice Agogino (ME faculty), Ali Elashri (MEng student) Austin Campbell (MEng student), Phil Marcus (ME faculty).

Final Presentation	Prototype Demo of 3D Morphed Model, Camouflage and Baseline Design