Wind Turbine Generator Knowledge and FAQ
Knowledge about wind generator
More info on Wind Turbines (Electric)
A wind turbine, which is installed on top of a tall tower, collects kinetic energy from the wind and converts it to electricity that is compatible with a home’s electrical system.
Wind turbines are a clean and efficient method of turning raw kinetic wind power into electric power. Wind turbines can be connected directly to machinery for mechanical energy or they can be connected to power generators and can create electricity. These three bladed structures, mounted on high poles or towers, are typically pointed into the wind using computers and sensors. The wind turbine itself is made up of a rotor mounted to a wind turbine generator which is mounted to a frame and then a tail is mounted on the opposing side of the rotor. If the wind turbine does not have a sensor based system pushing it into the wind, the tail will adjust it manually. Higher towers and broader rotors will generate more energy overall, so if you are considering the investment, understand that it is long term outlay and that the relatively low additional cost for a higher tower or larger rotor on your wind turbine will help offset the overall cost more quickly. As you consider your investment in a wind turbine generator, consider a hybrid power system using solar electric panels as well. Depending on where you live the seasonality of wind speed and the amount of sunshine produced in the warm summer months, you may find that you’ll reap more benefits from using all of your natural resources to power your home rather than just one or the other.
On grid or Grid-connected wind system
In a normal residential application, a home is served simultaneously by the wind turbine and a local utility. If the wind speeds are below cut-in speed， there will be no output from the turbine and all of the needed power is purchased from the utility. As wind speeds increase, turbine output increases and the amount of power purchased from the utility is proportionately decreased. When the turbine produces more power than the house needs, the extra electricity is sold to the utility. All of this is done automatically. There are no batteries in a modern residential wind system.
Will a small wind turbine save me money?
The wind turbine typically lowers your electricity bill by 50 to 90 percent. It is not uncommon for wind turbine owners with total-electric homes to have monthly utility bills of only $8 to $15 for nine months of the year. If less air conditioning is used the bills can be very low year-round. The amount of money a small wind turbine saves you in the long run will depend upon its cost, the amount of electricity you use, the average wind speed at your site, and other factors.
Who should consider buying a wind turbine?
A residential wind turbine can be a relatively large device and is not suitable for urban or small-lot suburban homes. Except for very small wind turbines (i.e., with rotors one meter or less in diameter) on very small towers, a property size of one acre or more is desirable.
The economics of a wind system are very sensitive to the average wind speed in the area, and to a lesser extent, the cost of purchasing electricity. As a general rule of thumb, if economics are a concern, a turbine owner should have at least a 10 mph average wind speed and be paying at least 10 cents/kWh for electricity.
Will it help the environment if I install a wind turbine at my home?
Yes. Wind turbines produce no pollution and by using wind power you will be offsetting pollution that would have been generated by your utility company. Over its life, a small residential wind turbine can offset approximately 1.2 tons of air pollutants and 200 tons of greenhouse gases (carbon dioxide and other gases which cause climate change).
Don’t I have to take wind measurements for a year or more?
For most residential systems the cost of taking wind measurements is not justified. Wind resource data published by the U.S. Department of Energy is sufficient for an experienced evaluator to predict wind turbine performance. In very hilly or mountainous areas, however, it may be best to collect wind data before purchasing a system to ensure that your site is not in a sheltered area.
Do wind turbines make noise or interfere with TV reception?
Small wind turbines do make some noise, but not enough to be found objectionable by most people. A typical residential wind system makes less noise than the average washing machine. Wind turbines do not interfere with TV reception.
Will my utility allow me to hook up a wind generator?
Federal regulations (specifically, the Public Utility Regulatory Policies Act of 1978, or PURPA) require utilities to connect with and purchase power from small (less than 80 MW) wind energy systems. A wind turbine manufacturer should be able to help arrange the required utility company approvals.
Will I have to change any of the wiring in my house?
No. A wind turbine is easily retrofitted to virtually any home without the need to change any wiring or appliances. In most cases, the utility will install a second utility meter to measure how much surplus electricity it is purchasing from the turbine owner.
What about towers?
Towers are necessary to raise the wind turbine above turbulence generated by obstacles on the ground and trees. Wind velocity and, therefore wind turbine performance, increases with altitude. Several different types of towers are available, depending upon which you select. Each type has its advantages; the most economical type of tower is the guyed lattice tower, but a hinged tower can be easier for you to install yourself and provides easier access for maintenance.
How reliable are wind turbines? Will I have to perform much maintenance?
Most small turbines have very few moving parts and do not require any regular maintenance. They are designed for a long life (up to 20 years) and operate completely automatically.
How do wind turbines perform as an investment?
The wind system will usually recoup its investment through utility savings within 6 to 10 years and after that the electricity it produces will be virtually free. Over the long term, a wind turbine is a good investment because a well-sited wind system increases property value, similar to any other home improvement. Many people buy wind systems in preparation for their retirement because they don’t want to be subject to unpredictable increases in utility rates.
Choosing a Home-Sized Wind Generator
You’re about to make the big decision: should a wind generator be in your future? You’ve analyzed your resources, both environmental and monetary, and weighed the pros and cons of having a wind generator. The only question left is: which system should you choose?
“what do you recommend?” is the most frequently asked question that I get. The answer—it all depends on your situation. I can honestly say that,properly specified and installed, any one of these machines will do a fine job of producing electricity for you for many years, in the right location.
If you install a light duty machine where the winds are severe, even for part of the year,you are asking for trouble.
If you install a light duty machine on a short tower where turbulence will be an issue, you are asking for trouble.
If you install a machine with lots of moving parts, knowing full well that you have no intention of climbing the tower to do maintenance and repairs, you are asking for trouble.
If you never do routine maintenance on your car or house, what makes you think you’ll do it on your wind generator?
All of these wind generators have their own personalities and idiosyncrasies, just like the cars we drive. And, just like the cars we drive, they come in a variety of shapes and prices. Finally, just like the cars we choose, they all will get us from point A to point B. However, not all cars, nor all wind generators, are created equal. As the saying goes, “You get what you pay for.” Quality always comes at a price. To quote longtime wind energy user and HP editor Ian Woofenden,“Remember, what you want is value. I put high value on low maintenance, long-term performance. You do not want to buy bragging rights to the highest peak output at the lowest price. Instead you want the most energy put into your battery or the grid for as many years as possible. That doesn’t come cheap.
How does it work?
Most small wind turbines generate direct current (DC) electricity. Systems that are not connected to the national grid require battery storage and an inverter to convert DC electricity to AC (alternating current – mains electricity)..
Wind systems can also be connected to the national electricity grid. A special inverter and controller converts DC electricity to AC at a quality and standard acceptable to the grid. No battery storage is required. Any unused or excess electricity may be able to be exported to the grid and sold to the local electricity supply company.
Is it suitable for my home?
Individual turbines vary in size and power output from a few hundred watts to 1kw – 6 kilowatts. Uses range from very small turbines supplying energy for battery charging systems to turbines on wind farms supplying electricity to the grid.
You should consider the following issues if you’re thinking about small scale wind. An accredited installer will be able to provide more detailed advice.
Wind speed increases with height so it’s best to have the turbine high on a mast or tower.
Generally speaking the ideal site is a smooth top hill with a flat, clear exposure, free from excessive turbulence and obstructions such as large trees, houses or other buildings.
Small scale wind power is particularly suitable for remote off grid locations where conventional methods of supply are expensive or impractical.
Small-scale building-integrated wind turbines suitable for urban locations are also available to install in homes and other buildings.
Please note that the electricity generated at any one time by a wind turbine is highly dependent on the speed and direction of the wind. The windspeed itself is dependent on a number of factors, such as location, height of the turbine above ground level and nearby obstructions. Ideally, you should undertake a professional assessment of the local windspeed for a full year at the exact location where you plan to install a turbine before proceeding. In practice, this may be difficult, expensive and time consuming to undertake. Therefore we recommend that, if you are considering a domestic building mounted installation and electricity generation is your main motivation, then you only consider a wind turbine under the following circumstances:
If you are in any doubt, please consult a suitably qualified professional.
Planning issues such as visual impact, noise and conservation issues also have to be considered. System installation normally requires permission from the local authority, so it’s important to always check with your local authority about planning issues before you have a system installed.
Turbines can have a life of up to 15 years but require service checks every few years to ensure they work efficiently. For battery storage systems, typical battery life is around 6-10 years, depending on the type, so batteries may have to be replaced at some point in the system’s life.
How Wind Turbines Work?
Wind is a form of solar energy. 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 flow patterns are modified by the earth’s terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.
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.
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.
Types of Wind Turbines
Modern wind turbines fall into two basic groups: the horizontal-axis variety and the vertical-axis design.
Horizontal-axis wind turbines typically have three blades. These three-bladed wind turbines are operated “upwind,” with the blades facing into the wind.
Sizes of Wind Turbines
Utility-scale turbines range in size from 100 kilowatts to as large as several megawatts. Larger turbines are grouped together into wind farms, which provide bulk power to the electrical grid.
Single small turbines, below 100 kilowatts, are used for homes, telecommunications dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations, where a connection to the utility grid is not available.