FAQs

What is wind energy?

Wind energy is the energy contained in the movement of air, known as wind. The sun heats the earth at different rates and at different times. The difference in temperature throughout the earth generates pressure differences that in turn drive the movement of air. Air has mass and when a mass is put in motion it contains what is called kinetic energy, much like a baseball thrown by a pitcher.

Wind energy has been used for centuries to drive pumps and mills by taking the kinetic energy and converting it to mechanical energy through the use of windmills. This same concept is used to convert kinetic energy into electrical energy through the use of wind turbines.

What is a wind turbine and how does it make electricity?

A wind turbine is a machine that harnesses the kinetic energy in the wind and converts it to electrical energy. Mechanical energy created by its rotating blades turns a generator that creates electricity. A typical wind turbine consists of the following features:

What is a kW and what is a kWh?

A kW (kilo-watt) is a rate of energy production or consumption, and a kWh (kilo-watt-hour) is a unit of energy.  Think of it like driving in your car.  Miles per hour is a rate at which you produce distance with your car and a mile is a unit of distance.  For example if you drive for 1 hour at 60 miles per hour you have traveled a total of 60 miles.  Similarly if you produce 60 kW of power for an hour you have produced a total of 60 kWh.

How big is a wind turbine?

The size of wind turbines varies and is directly related to its designed electrical output. For example, the electrical output of a 10kW turbine at maximum windspeed can produce 10 kilowatts of electricity. Utility-scale turbines used for wind farms and utility-scale onsite projects can vary from 100kW to 5MW and have rotor diameters of 21m to 100m respectively. Tower heights of these turbines can also vary from 40m to 90m. Smaller turbines used in residential and agricultural applications are typically less than 100kW and have rotor diameters less than 21m. Towers heights can vary from 15m (or less) to 40m.

How much electricity can one wind turbine generate?

The amount of electricity produced by one turbine depends on its size and quality of wind resource. For example, a 1MW turbine, if placed in an appropriate wind resource, can generate approx 2.5 to 3.5 million kWh annually, enough electricity to supply approx. 250 to 300 homes. However this number is only a helpful way to translate electrical production into familiar terms. A wind turbine is not always generating power and therefore cannot constantly supply electricity to a home. Similarly, a 10kW turbine with sufficient wind resource can generate approx 10,000 kWh annual, enough energy to supply a single home (depending on usage over the course of a year).

How much noise does a wind turbine make?

With advances in the engineering and manufacturing of wind turbines, the noise generated is negligible. Any noise generated is usually from the mechanical components and the rotation of the blades. The mechanical components and blades of a turbine, especially larger machines (100kW and above), have been purposely engineered to produce minimal noise. Some have compared the noise generated to that of a clothes dryer. With smaller machines, less than 100kW, turbine noise is primarily generated by the rotation of the rotor blades, since mechanical components are usually small and kept to a minimal. Siting the turbine at appropriate distances from occupied buildings also minimizes any potential disturbance from turbine noise.

What does SED do?

SED has evolved a good amount since it was founded in April of 2002.  Initially SED’s focus was on the installation and maintenance of metrological towers and as a consultant to large-scale wind developers.  Since then SED has narrowed its focus to the development, design, construction and maintenance of on-site and decentralized wind projects.

What is on-site power generation?

On-site generation also known as “distributed generation” is the generation of power near the location where it will be consumed.  Most of the electricity an average person uses is part of a “centralized” system where large amount of power is produced in a small number of locations (power plants) and transmitted to end users.  More and more people are realizing the benefits and merits of moving towards the decentralized or onsite generation model of power production.  On-site wind power generation can be anything from a 10kW wind turbine to help produce power for your home to one or more megawatt size wind turbines helping to power a manufacturing facility.

Is there advantages of on-site generation over the traditional “centralized” model?

First it is important to realize that it would be difficult for the electric grid to remain stable solely with distributed generation, so centralized generation is still a very important and a critical part of the overall system.  That being said some of the advantages of distributed generation are:

Less electricity wasted in the delivery process- With centralized power production, the electricity produced needs to travel through miles of transmission wires before it arrives at your location to be consumed.  No matter what, a portion of that electricity is lost traveling through those lines.  With distributed generation system, the power is produced near where it is consumed so electric line losses are minimized.

Taking control of your power generation- Energy flows in electric grid to the area of least resistance.  Regardless of who you “purchase” electric supply from the actual electrons could come from any number of nearby power plants. (Think of the electric grid as a pool of water… suppliers dump water in and consumers scoop water out with little choice of who’s water you are actually taking)  With On-site generation you actually know exactly where a large portion of your power is produced and how it is produced.  By knowing that the wind turbine on your property is actually powering the lights in your home or business, you ensure your energy consumption is from a clean source.

Long term savings – The installation of an on-site wind turbine requires a large upfront cost and a small amount of operations and maintenance costs throughout its lifecycle.  Over time the wind turbine will pay for itself in energy savings, and you will pay significantly less money in the long run than if your purchased your power the traditional way, exclusively from a utility.

Is it possible to make money or see large economic returns by putting up a large wind turbine and selling that power back to the utility?

More likely than not the answer to this question is No, because doing so would mean that you are competing with large wholesale energy generators such as coal, oil, nuclear, natural gas plants or large wind farms.  One of the largest advantages of on-site generation is that you are offsetting your own high cost retail energy.  By way of example, lets say you pay 13 cents per kWh for energy at a manufacturing facility and the current wholesale cost of power is 6 cents per kWh.  Every kWh of power you produce for yourself and consume at your facility means you don’t have to pay the utility 13 cents.  If you produce more power than you need and sell it back to the utility they will give you 6 cents.  The money you don’t pay because you produced your own power and the money you get from the utility for selling them power is essentially the “value” of the power you generate.  The more of your own power you supply the closer to 13 cents a kWh the power produced by your wind turbine will be worth, the more you sell back to the utility the closer to 6 cents a kWh the power produced by your wind turbine will be worth.  The higher overall “value” of the power you produce will dictate economic indicators such as payback period directly.

What is net metering?

Renewable energy sources such as solar and wind produce power intermittently, meaning their output varies greatly hour-to-hour and day-to-day.  With a properly matched wind turbine there will be times when it is producing no power (not enough wind) and times when it is producing significantly more power than needed (plenty of wind).  Without net-metering any power that is produced above what you need is sold back to the utility at wholesale pricing.  With net metering, any excess power essentially turns your electric meter backwards and you can receive that energy back on non-windy days at a net cost of zero.  Another way of thinking about it the electric grid can serve as battery backup where excess energy is stored for future use.  The availability and specifics of net-metering depends on your local market and the size of the generator.

Is there funding opportunities to help pay for a wind turbine or wind studies?

Absolutely, but the amount and type of funding varies greatly depending on factors such as:

• What state you are in.
• If it’s for a public or private business.
• The size of the installation
• If there are agricultural or educational ties to the project.
• What electric utility serves you

A qualified wind consultant will be able to help you sort through what type and amount of funding is available for your specific project and location.

Do I need to do a feasibility study before installing a wind turbine?

Generally the need for a feasibility study depends on how big the project is and what degree of confidence is needed for the investment to be made.  In addition, most funding agencies will require some form of feasibility study before a project will qualify for large design and construction grants.

How much does a feasibility study cost?

This cost of feasibility study can depend on many factors.  For a 10kW wind turbine, typically the free initial analysis we perform is all that is needed.  For a large project like the 1.5MW wind turbine at Jiminy Peak, a more in-depth study was required for the Massachusetts Technological Collaborative (MTC) to provide funding, as well as for financiers to invest in the project.  Every project is going to be different and aside from any specific grant contingencies, the study serves to satisfy the parties investing in the project at a level of confidence indicative of the size of investment needed.  Currently, SED’s feasibility studies for a single turbine range from $20,000-$100,000.