Green Renewable Energy

Wind power is considered by many as an emerging technology, the truth of the matter is we have been using wind power for many hundreds of years to grind our corn and even for milking our cattle. With the dawn of the industrial revolution the use of wind to power machinery
fell by the wayside as steam and eventually electricity grew in popularity.

Recent environmental concerns have made way for the return of wind power, and in its wake came a host of myths, mistruths and misunderstandings. This article aims to dispel some of the common myths of wind power.

Wind turbines are only efficient in high winds
This is a common misconception regarding wind turbines. Obviously the more wind there is the more electricity each wind turbine will generate, but even in a light breeze both large commercial wind turbines and the smaller residential wind turbines will generate an acceptable amount of electricity. As the wind speed changes, the angle of the turbines blades will adjust themselves accordingly to achieve maximum efficiency, regardless of wind speed.

Wind turbines are noisy
This may have been true in the past as many early wind turbines had no noise emission guidelines to adhere to. Also, wind turbine manufacturers and wind power companies didn’t really consider the impact a large scale wind farm would have on nearby residential areas. These early wind turbines are the source of the current ‘wind turbines are noisy’ myth. Over the last decade wind turbine technology had progressed considerably, rendering mechanical noise almost undetectable.

Wind farm planners have strict guidelines to adhere to in order to protect nearby residential areas from noise emissions. This doesn’t mean that wind farms are silent as there is an audible ‘swoosh’ as the turbines blades pass the tower; however this is only heard at a relatively close range.

Wind farms are not cost effective
Twenty to thirty years ago, wind farms and wind turbine technology was a victim of trial and error to a certain extent. Let us not confuse older, noisier and more costly wind farms with their modern counterparts. In the early 1980’s over 5000 wind turbines were put in place at the Tehachapi Pass in California. These days wind farms consist of fewer, larger wind turbines which have proved not only more cost effective but more attractive on the eye than the early wind farms which dotted the landscape with hundreds of smaller wind turbines.

Home wind turbines are a waste of time and money
The smaller home wind turbines are more often than not used in combination with an array of solar panels. The wind turbine will continue to charge the batteries through the night even in a light breeze meaning a steady trickle of electricity is potentially available 24 hours a day. Prices of home wind turbines vary depending on the output power and installation cost. A small residential wind turbine will reduce an average electricity bill by around 20-35%. Or to put it another way, a residential wind turbine would save around half a ton of CO2 each year.

Wind farms kill birds
It is true that a considerable number of birds have flown into the blades of wind turbines and as a result have been injured or even killed. Saying that, it is also true that a large number of birds are killed each year as a result of flying into tall buildings or are hit by cars, trains, trucks and busses. It is an unfortunate fact that human impact on the environment does take its toll on wildlife to a certain extent; however, wind farms do not pose any considerable threat to birds or any other form of wildlife.

Small wind-electric systems can provide electricity to many differnt areas. Although wind systems require more maintenance and need more attention than solar-electric, if you invest up front in good equipment, design, and installation, wind-electric systems can make economic and environmental sense.

They also bring a great deal of satisfaction—there´s nothing quite like watching your wind generator convert a summer breeze or a winter storm into electrical energy.

How It Works

Boiled down to its simplest principles, a wind generator´s rotating blades convert the wind´s kinetic energy into rotational momentum in a shaft. The rotating shaft turns an alternator, which makes electricity. This electricity is transmitted through wiring down the tower to its end use.

The blades must turn to face the wind, so a yaw bearing is needed, allowing the wind turbine to track the winds as they shift direction. The tail directs the rotor into the wind. Some sort of governing system limits the rotor rpm as well as generator output to protect the turbine from high winds. A shutdown mechanism is also useful to stop the machine when necessary, such as during an extreme storm, when you do not need the energy, or when you want to service the system.

How To Choose A Wind Turbine

Trying to keep an inexpensive wind generator running can be an uphill battle that you´ll soon tire of. But expect to pay more for a better machine—it´s a tough job to design and manufacture a long-lasting, small-scale wind generator.

The bottom line: Buy a turbine that has a very good track record and a good warranty—five years is preferable but not always available in the small wind industry.

Batteryless Grid-Tied Wind-Electric System

Connecting to the grid without batteries is the most cost-effective and environmentally friendly way to go. You eliminate batteries, which are costly, require maintenance, and carry a significant efficiency penalty. The only drawback of batteryless systems is that when the grid is down, your system shuts down. But in most grid-serviced areas, utility outages are only a few hours a year—a small inconvenience to endure for the efficiency, environmental friendliness, and thriftiness of these systems.

Grid-Tied Wind-Electric System with Battery Backup

Connecting a wind-electric system to the utility grid with battery backup gives you the best of both worlds. You have the unlimited capacity of the grid at your disposal, and you can send your surplus wind energy to the grid. When the grid is down, you can still use your system, within the limitations of the battery bank and turbine.

Off-Grid Wind-Electric Systems

Off-grid wind-electric systems are battery based. People generally choose these systems because their home or other energy use is not connected to the grid, and connection would be expensive. Others prefer the independence of off-grid systems, or live where utilities and governments make it difficult to tie a renewable energy system to the grid.

solar power for the home

Solar electricity, or photovoltaics (PV), is a thriving business worldwide. It makes good on its promise of “delivering clean, reliable, on-demand power.”

Research progress continues, better positioning current and next-generation photovoltaic (PV) technologies to meet future electricity needs. But these successes seem to spark some criticisms and questions. Some are warranted. Some are based on partial truths. And others are perpetuated from urban legends or myths about the technology.

Common among these criticisms and questions are the seven myths of solar electricity:

• Myth 1: Solar electricity cannot serve any significant fraction of U.S. or world electricity needs.
• Myth 2: Solar electricity can do everything — right now!
• Myth 3: Photovoltaics cannot significantly offset environmental emissions.
• Myth 4: Photovoltaics is a polluting industry.
• Myth 5: Photovoltaics is merely a cottage industry, appealing only to small niche markets.
• Myth 6: PV is too expensive and will never compete with “the big boys” of power generation. Besides, you can never get the energy out that it takes to produce the system.
• Myth 7: Nothing remains to be done. Essential R&D is complete, the product works — just close the laboratory doors and let industry fight it out.

Here are the facts behind the myths:

1. PV technology can meet electricity demand on any scale. The solar energy resource in a 100-mile-square area of Nevada could supply the United States with all its electricity (about 800 gigawatts) using modestly efficient (10%) commercial PV modules.
   A more realistic scenario involves distributing these same PV systems throughout the 50 states. Currently available sites—such as vacant land, parking lots, and rooftops—could be used.
2. No way. Solar electricity will eventually become a major player in the world’s energy portfolio. The industry just doesn’t have the capacity to meet all demands right now.
3. PV systems produce no atmospheric emissions or greenhouse gases. Also each kilowatt of PV electricity annually offsets up to:
   • 16 kilograms of nitrogen oxides
   • 9 kilograms of sulfur oxides
   • 2,300 kilograms of carbon dioxide (CO₂)
4. The PV industry is neither “squeaky clean” nor a major environmental, safety, or health problem. When it comes to emissions, PV’s electricity-generating portion of the fuel cycle is the clear winner versus fossil fuel sources. However, semiconductor processing can involve the use of chemicals and toxic materials.
5. This is a real business — one that has been growing by more than 35% per year over the past 2 years. In 2001, PV module shipments closed in on the 400-megawatt mark, representing a $2.5 to $3 billion market. The U.S.-based industry itself is now approaching $1 billion per year and providing 25,000 jobs. It’s expected to grow to the $10-$15 billion level in the next 20 years, providing 300,000 jobs by 2025. This sustained growth exceeds that of the semiconductor industry.
6. The cost of producing PV modules, in constant dollars, has fallen from as much as $50 per peak watt in 1980 to as little as $3 per peak watt today. This causes PV electricity costs to drop 15¢-25¢ per kilowatt hour (kWh), which is competitive in many applications.
7. As high-tech energy production, PV has immense potential to evolve, develop, and advance. Our current technologies still have substantial potential for improvement.
   Research and development (R&D) in processing, process understanding, and manufacturing remains in its infancy. There is much important R&D still to be performed, not just on cells and modules, but also on balance-of-systems components and on systems themselves.