Wind energy is the fastest growing source of renewable energy in the world with a projected annual growth rate of more than 20 percent, generating more than 15,000 additional megawatts per year. The United States alone increased its facilities by 4,000 megawatts in 2007, and Colorado is among the leading states with the sixth-largest wind power capacity in the country, according to the American Wind Energy Association.
So it should be no surprise that CU-Boulder is among the leaders in wind energy research and education. CU faculty are advancing wind power technologies for greater cost-efficiency, power capture, and safer operation, while launching a number of educational initiatives to respond to student interest in the field.
A course focused solely on wind energy was introduced by the mechanical engineering department in spring 2007, and electrical and computer engineering faculty are following up this spring with an energy course on renewable sources and efficient electrical energy systems.
ECE faculty also have proposed a new undergraduate degree in electrical and energy engineering that would include energy-related courses on such topics as energy conversion and power systems, renewable energy, and power electronics; and electives in wind power, photovoltaic materials, and photovoltaic systems. If approved, the degree would be the third undergraduate degree program offered by the ECE department.
In research and development, ECE Professor Lucy Pao is working with the Colorado Renewable Energy Collaboratory to establish a Front Range wind energy center. The collaboratory is a partnership among the state’s premier research universities—CU-Boulder, Colorado State University, and the Colorado School of Mines—and the National Renewable Energy Laboratory (NREL) located in Golden, developed to increase the production and use of energy from renewable resources. Formed in early 2007, the partnership already has spun off a research and education center focused on biorefining and biofuels, and a number of other focused centers also are in the works.
Pao says that even though wind energy is priced competitively with coal and natural gas, the technology still has pressing problems that need to be remedied. Among these are the need to control wind loading to mitigate turbine damage and avoid shut-downs during high wind conditions, to optimize turbine control for greater efficiency of operation, and to determine turbine placement within wind farms and coordinate control for the best overall capture and generation of power.
A specialist in control systems, Pao and her research group have been investigating novel controls for variable-speed wind turbines, which are designed to follow wind-speed variations to maximize aerodynamic efficiency.
"Advanced control methods can make a significant impact on the generator torque control and blade pitch control," she says. Generator torque control determines how much torque is extracted from the turbine, while blade pitch control is used to mitigate structural loads in high wind conditions. The control of floating wind turbines for deep water applications is another area under development.
The Colorado Power Electronics Center in the ECE department also is active in renewable energy systems. CoPEC faculty conduct research in high-frequency, high-efficiency power converter technology, advanced analog and digital control techniques, and mixed-signal integrated circuit design for power management. They also do research in power electronics for photovoltaic power sources, and in high efficiency lighting systems.
Graduate students working with Professor Frank Barnes, meanwhile, have been investigating storage systems, which will become increasingly important as wind generation grows to be a larger part of the energy grid. One technology they are looking at is utility-scale pumped hydroelectric storage, which could handle the intermittences inherent in wind generation without the need for spinning reserves of fossil fuel, Barnes says. Such a system, which would use wind energy to pump water upslope during off-peak times and then release the water to address peak power needs,could be ideal for western Colorado.
Another storage technology being studied would use an underground aquifer as the pumped hydroelectric system’s lower-level reservoir for agricultural applications, while a third involves storing wind power as compressed air in underground wells or abandoned coal mines in the eastern part of the state.