There's been a lot of talk about solar power, but what about wind? Wind energy is a great complement to solar since it works day or night. Along with geothermal and hydro energy, these renewable energy sources are the key to our transformation to a post-carbon economy. Wind energy, for instance, is a key ingredient for the United Kingdom’s future energy growth and plan to reduce carbon emissions.

“I think the United States could do a better job educating people on green initiatives, comments Dawn Herring, member of the Wind Generator senior design project team at Stevens Institute of Technology. “Just last year Stevens, for example, introduced the green minor.  It’s a new and exciting program which focuses on improving global scale sustainable energy and systems using available resources.”

Government policy is certainly lining up behind more small-scale resources.  Recently, President Obama signed into law the American Recovery and Re-investment Act of 2009. With a significant emphasis on renewable energy technology innovations, the bill allows homeowners and small businesses a hefty tax deduction off the installed cost of a wind turbine.

Stevens engineering graduate, Christine Couzo,  comments, “With Stevens investing in solar panels our team figured, why not do some good?  We could create another renewable energy source here on campus.”  That’s exactly what this team did when they proposed to harness wind on the Babbio Center roof.

Advantages  of Wind Energy

Wind energy is versatile and offers many advantages, which explains why it is the fastest growing energy source in the world. First, it is a clean energy source meaning there is no resulting pollution. This energy doesn’t rely on combustion of fossil fuels and produces no atmospheric emissions that contribute to the causes of acid rain and global warming through greenhouse gases. Second, wind is an infinite source that can be implemented anywhere there is wind, rural or urban areas, large scale wind farms, or small scale micro turbines. Finally it is the cheapest renewable energy to implement and maintain.
Says Couzo, “I think it’s good to invest in something you know can’t go wrong.  Fossil fuels will run out - there is not an infinite source of fossil fuels. It’s about evolving and creating technologies that you can implement on a forever basis. “

What Is Wind Energy

Renewable energy is energy generated from natural resources—such as sunlight, wind, rain, tides and geothermal heat—which are renewable (naturally replenished).  Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind resources are best along coastlines, on hills, and in the northern states, but usable wind resources can be found in most areas. Wind resources are influenced by terrain and other factors that make it much more site specific than solar energy. “Turbine engines were mounted on the Babbio roof with a mount designed and fabricated by students,” reports Herring.   “For our project, we used the natural local resource, which is the wind.”

In hilly terrain, for example, you and your neighbor are likely to have the exact same solar resource. But you could have a much better wind resource than your neighbor because your property is on top of the hill or it has a better exposure to the prevailing wind direction. Conversely, if your property is in a gully or on the leeward side of the hill, your wind resource could be substantially lower. In this regard, wind energy must be considered more carefully than solar energy.

“The public needs to understand that it’s beneficial to get your electricity from solar energy or wind resources and not from fossil fuels,” reports Couzo.  “This can also sustain or maintain our natural environment.”

How Wind Energy Is Harnessed

The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.

A wind turbine is a rotating machine which converts the kinetic energy in wind into mechanical energy. If the mechanical energy is used directly by machinery, such as a pump or grinding stones, the machine is usually called a windmill. If the mechanical energy is then converted to electricity, the machine is called a wind generator, wind turbine, wind power unit (WPU), wind energy converter (WEC), or aerogenerator.

Turbines used for commercial production of electric power are usually three-bladed and pointed into the wind by computer-controlled motors. These have high tip speeds of up to six times the wind speed, high efficiency, and low torque ripple, which contribute to good reliability.


How Wind Turbines Work

So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.

Herring describes the team’s design process.   “We implemented micro-turbine as a feasibility study of a 20 unit design system. Our system creates electricity. The wind hits the blades, turning the blades, which then cycles the generator,” she says. “The generator creates a current into the inverter, which translates into an alternating current.  Basically, it’s a pinwheel with a coil.”

What’s the next challenge for these industrious engineers?  “I was hired as an energy analyst for a company generating electricity and natural gas,” remarks Couzo.  “Being an environmental engineer now offers great opportunity.  There’s a huge job market  since it’s a relatively new area of engineering.”

Adds Herring, “When you study environmental engineering, you lead the pack in a any job market. We all have starting salaries that are well above average.”