Category Archives: Wind Energy

Latest developments in Wind energy use.

Wind Energy and Bats

At the zoo there is a lady I know who cares a lot about bats, she pretty much knows everything one needs to know about them. Some time last year at one of our gatherings she was talking about bats being killed by the wind turbines. She said hundreds of bats were dying around wind turbines in the midwest, so it set me searching to find what was going on.

Some Interesting Bat Facts

Bats are an essential part of our environment, they keep pests in check and are also pollinators for many plants  and trees.

Their names have been maligned by misinformation and myth over centuries.

Of the 1100 species of bats only 3 species of bats feed on blood or are vampires, which do not suck blood but make a cut and lick blood. All 3 are found in South America only.

Bats are mammals.

Bats do use echolocation to fly during the night, but unlike most people believe they do have excellent eye sight.

Most migratory bats are solitary.

Most bat species eat insects, while many tropical species feed exclusively on fruit or nectar.

Bats are, for their size, the slowest reproducing mammals on earth. On average, mother bats rear only one young per year, and some do not give birth until they are two or more years old.

Bats can live up to 40+ years!

Bats have inspired characters from Villains to Superheros! Dracula to bat man 🙂

Wind Turbines and Bats

I came across two articles on the subject the earlier one from 2008 on spoke about how wind turbines were killing bats without hitting them and the other in the National geographic from yesterday was tilted Hope for stemming wind energy’s toll on bats.

The article says that a study conducted had come to the conclusion that most of the bats flew into the low pressure area behind the will turbines which resulted in their little lungs rupturing and causing their deaths, some died by being hit by the turbine tips. The annual bat fatality in West Virginia alone is estimated to be between 1500-4000 bats. Nationally the numbers are much larger. Bats being nocturnal and so tiny, are difficult to keep track of. Before them dying under the wind turbines no one really saw them unless they went looking for them.

Most of the impacted bats are migratory bats which some how seem to drawn to the wind turbines at night. Bat experts have been working for a solution to this problem and some have suggested an ultrasonic sound to be added to the wind turbines (no one is sure about the long term effects of ultrasonic sounds on bats and other wildlife).

Ed Arnett director of Bat Conservation International suggests that wind turbines be turned off when the bats are most active i.e. night. They have been working with a wind energy producer and have seen bat deaths drop by 20-50% as a result. Another solution could be to increase the minimum wind speed needed to set the blades in motion. Most bats are more active in low wind.

As the concern over the high number of bat deaths increased it led to the formation of The Bats and Wind Energy Cooperative (BWEC) in 2003 by Bat Conservation International (BCI), the US Fish and Wildlife Service, the American Wind Energy Association (AWEA), and the National Renewable Energy Laboratory of the US Department of Energy (NREL).

Hopefully something will be done to safe guard the bats right to fly as it has for generations. It is frustrating when we seem to ignore an issue that stares at us just because it does not have a pretty face or loud enough voice.

Sources :

National Geographic Article Article

New Scientist

Bat Conservation International

Futuristic Off Shore Wind turbines: The Wind Lens

Kyushu University professor Yuji Ohya has developed an ultra efficient wind turbine which is unlike anything we have seen before. At the Yokohoma Renewable Energy International Exhibition 2010, Professor Ohya and his team unveiled the Wind Lens, a honeycomb-like structure which supposedly triples the amount of wind energy that can be produced by off shore turbines.

The basic tenet of the Wind lens is kind of like a lens concentrating solar energy onto photo voltaic surfaces, here the ring like structure “the hoop” acts like a wind collector concentrating the wind onto the turbines. The structure has a 112 meter diameter and supposedly will also reduce noise pollution. According to reports verification experiments show that wind lens turbines produce 3 times as much electricity as those without a hoop.

According to Professor Yuji Ohya  even a gentle breeze can accelerate the revolution of the turbines considerably. The 2.5 meter-wide blades can, at with wind speed of 5 meters a second, can provide a sufficient amount of electricity to power an average household. There is a diffuser placed along the edge of the turbine which does not rotate there by reducing the vortices and increasing efficiency.

The smaller size of the turbines could in the long run make it cheaper to manufacture, for now though they are pricey.

My Opinion

To me anything that interferes with the Ocean and is man-made is not safe until proven safe for the environment around and in the Oceans. So though impressed by the design aspect and the increased efficiency of the wind lens I will wait to see the environmental impact studies.

Check out Professor Yuki Ohya’s website for more details here

Read more about the Wind Lens and Yokohoma Exhibition here

CNN article here article is here

Airborne Wind Turbines: The Future of Wind Energy?

“Wind” movement of air caused by differences in temperatures in the earth’s atmosphere. Wind which is everywhere around us in abundance has been harnessed for centuries. We at Connect-Green keep an eye out for the latest developments on the evolving trends in the alternative energy sector as we believe that is where the future is.

Joby Energy a wind energy company based in Santacruz California is one such innovator. They have been developing airborne wind turbines which harness the winds at higher altitudes. Going higher means an increase in the velocity of the wind. Higher speeds at greater altitudes should produce a higher energy output. The idea for harnessing the high altitude wind has been around since 1970’s but was deemed non-viable.

The System

Their multi-wing structure supports an array of turbines. The turbines connect to motor-generators which produce thrust during takeoff and generate power during crosswind flight. Orientation in flight is maintained by an advanced computer system that drives aerodynamic surfaces on the wings and differentially controls rotor speeds. A reinforced composite tether transmits electricity and moors the system to the ground. The tether that moors the turbine to the ground has electrical conductors inside, which transmit generated electricity from the vehicle to substations.

After testing more than 20 different prototypes, the company has settled on a 30kW system, which it is using to evaluate the efficiency of the design. If successful, it intends to pilot test a 100kW prototype within the next year.

The firm’s goal is to create an initial line of systems with a power capacity of 300kW which would be capable of generating enough energy to power around 150 homes. Larger systems of 3MW or more could potentially power 1500 homes.

What makes their system better than the surface-based systems? According to Joby Energy these are the significant features:

  • Produce energy more consistently. Because they are operated at higher altitudes, the system produces twice the energy for the same rated power. Consistent winds at higher altitudes allow their system to achieve a net capacity factor of approximately 70% versus 35% for surface-based systems.
  • Require lower capital costs. Building their system requires significantly less materials than a surface-based turbine (approximately 1/20), resulting in low capital costs for the given rated power.
  • Deliver the most cost-effective renewable energy. Consistent energy production and low capital costs result in energy production cost per kWh lower than all other renewable sources.

Joby energy website says “High-altitude wind has between 2 and 30 times more power density than surface wind. This is because of two factors: First, the power in the wind decreases linearly with decreasing air density, so air that is one-third as dense contains one-third the power. Second, the power contained in the wind increases as the cube of speed, so five times the wind speed yields 125 times the power. Equally, if not more important is that high-altitude wind is significantly more consistent than surface winds. Even during times of low wind, our system can tack across the sky on the tether, thus maintaining consistent output.”

Many other companies like the Ottawa based Magenn Power,  Sky Windpower and the Italian firm Kitegen Research are also researching the options to capture the high altitude winds for a greener energy future.

“It’s not like the more you use it, the more you run out… It doesn’t matter how much you use it. It’s still there every day. It’s free energy, continuously guaranteed as long as the Earth is what it is. –Cristina Archer, Assistant Professor, Department of Geological and Environmental Sciences, California State University – Chico

Let’s hope sometime soon we will have a solution to harness high altitude wind for a Greener and more wallet friendly solution to replace our dependence on non-renewable energy sources. Live Green!


Joby Energy Website


Wind Energy Good News for Small turbines

Picture Source skystream

Wind energy is on the move! literally! It is good news for the Small wind turbine market. As per the AWEA’s latest report 2010 AWEA Small Wind Turbine Global Market Study despite the recession and economic downturn the US market for small wind turbines grew 15% in 2009 with 20.3 Megawatts of  new capacity and $82.4 Million in sales! Small wind turbines are those with rated capacities of 100 kiloWatt or less. This increase suggests an addition of 10,000 units pushing the total installed capacity to 100Megawatt.

Wind energy has a history of 80 years and more than half of the growth has been in the last 3 years when the price of petroleum sky rocketed and the issue of clean energy came to the fore front.

The 2009 Amercian Recovery and Reinvestment Act expanded the Federal Iinvestment Tax Credit (ITC) for small wind turbines, allowing consumers to take fully 30% of the total cost of installing a small wind system as tax credit. Private investors also helped the economy  by pumping in investement  into wind turbine manufacturing.

Some key points and data from the report :

  • 95% of all small turbines sold in the US were also manufactured in the US!
  • 2/3rd of all wind turbines sold the world over were manufactured in the USA.
  • Approximately 250 manufacturers around the world manufacture or plan to manufacture small wind turbines, of which 95 are based in the USA.
  • Most wind turbines have a 15-25 year life span and minimum maintenance if any.
  • The federal ITC provided a monetary impetus & in addition gave the industry a positive boost making it more viable to investors, state governments and media alike.
  • A Property Assessed Clean Energy (PACE) bond is a financial tool which helps consumers with the high initial investment cost of renewable energy equipment. It is available in 18 states now.
  • Approximately 100,000 units of small wind turbines have been sold in the US since 1980.
  • Manufacturer’s say the fastest growth last year was in the Midwest states.
  • In the recent years these states showed the highest sales percentage : California, Nevada, Arizona, Oregon, New York, Massachussets and Ohio. The State governments have played a big part in making this happen by providing incentives and helping with streamlining permitting laws.
  • Poor or nonexistent local permitting laws hinder installation of about 1/3rd of the planned small wind turbine installations.
  • Standardizing and simplyfying grid interconnection procedures will help promote all alternative energy installations.

A single residential scale turbine displaces (or reduces) Carbon Dioxide produced by 1.5 average cars!

100 MW cumulative small wind energy installations total to approximately :

  • 17,000 cars removed from the road
  • 12,000 equivalent numbers of homew powered
  • 101,000 tons of Carbon Dioxide displaced!!


The report says the following about demand for small wind energy systems. Economically investors look at the Internal Rate of Return (IRR) of renewable energy sources as a better way to assess its value istead of the payback period. Hedging against the rising price of conventional electricity and it being market dependant where as alternative energy prices are steadier once installed.

Small wind turbines integrated with a hybrid Solar system is becoming a practical option for home owners. Zero Energy Home is a very attractive proposition in a volatile energy market. there is also the charm of owning one’s own electricity instead of renting!

Pricing is always a big worry on everyone’s mind as one considers an alternative energy source, same is true for wind. On the web there are pricings from

Price ranges for small wind turbines – and even for a single model – vary widely due to the numerous factors affecting installation, but costs for a well-sited turbine tend to gravitate between $3 – 6 per Watt, and $0.15 – $0.20 per kilowatt-hour. Costs and cost-recoupment periods can vary due to the following factors, ranked in approximate order of importance:

  • Availability and quality of state incentives and state/utility net metering policies
  • Average annual wind speed
  • Prevailing costs of traditional electricity. Installations tend to be most cost-effective in regions where the cost of utility provided electricity exceeds $0.10 per kWh.
  • Cost of equipment, installation, and maintenance.
  • Estimated operations and maintenance (O&M) costs average $0.01 – $0.05 per kWh. Other calculation methods place O&M costs at roughly 1% of the retail cost of an installation, accrued annually.
  • Sales and property tax rates (and incentives).
  • Raw manufacturing materials.
  • Insurance.
  • Method of financing.
  • Permitting costs, which can range from $0 to $1,000+ depending on the zoning jurisdiction.
  • Application type.
  • Installations for businesses may benefit from special tax incentives.

5 Leading Manufacturers of small wind energy systems as of 2009 are (in order of total kiloWatts sold world over)

  1. Southwest Wind Power (US)
  2. Northern Power Systems (US)
  3. Proven Energy (UK)
  4. Wind Energy Solutions (Netherlands)
  5. Bergey Wind Power (US)

Hoping this trend will continue! Green is a new lifestyle! and it is even more attractive when financially viable. There is talk about a legislation in 2010 which will try to create a nationwide requirement for all major utilities to derive a certain percentage of their energy generation from renewable sources. This is called Renewable Energy Standard or RES, which is in place in 28 states already.

You can read the entire report here

Check out a small wind turbine system from Skystream here

Source for picture :

Graphs :

Your Own Wind Turbine Basics

Picture courtesy Dhruv

Wondering about How to get a Wind turbine for your home? Wondering whether it will be worth it? Wondering what, how etc… Then read on…

Before starting realize if you don’t live in a plot around an acre in area it is better to not to go for full fledged wind energy.

Reasons – Turbines needed to generate enough power to run a home are generally large and noisy. The standard towers stand at 80-120 feet with turbine blades between 10 -20 feet.

Simply put wind turbines collect kinetic energy (energy from the moving wind which turns the blades) and convert it into electricity usable in homes. If you live in a neighborhood with decent wind during most of the time (7-10 miles per hour minimum) meaning open areas around etc that will help. Homes are also connected to a local utility just in case there is not enough wind. When your turbine produces power you use it and sell the excess back to your utility (check with your local utility whether they have the set up for that).

Before thinking about going with wind turbines find out whether there are any zoning or other restrictions in your area. Some restrictions might cap the height of structures allowed in an area etc…  Also whether your utility company is set up to buy back the excess power you may generate, meaning a grid connected system. Stand-alone wind energy systems can be economically viable for homes, farms, or even entire communities (a co-housing project, for example) that are far from the nearest utility lines.

Size of the Turbine – In general homes use around 800-2000kWh per month, there by requiring a 5-15 kilowatt range turbine (which will again depend mainly on the wind in your locality).  The towers are generally 80-120 feet tall and the rotors around 10-60feet in length. Smaller turbines have rotor blades between 3feet to 4 feet in length.

Price – A standard home wind turbine can cost 6000 to 22,000$ as per the manufacturers charges based on the size, application, service agreements and installation. There are 2kWh turbines available from around 2000$ and smaller 450Watt turbines for less than 1000$. A wind turbine will lower your power bills by 60-90%. One good thing is the larger turbines are made to function smoothly without major maintenance for up to 20 years.

If economics is of concern make sure you have a steady wind of around 10mph for a steady production of electricity. Check your wind resource here or get an anemometer for around 500-1500$ to measure the wind in your site.

Another option is to have a hybrid system ie a system with a photovoltaic cell system (Solar) so that it will make up for lower wind speeds in summer when the Sun shines bright!

Once you invest in a wind turbine, be ready for the long haul it is a long time investment for economic and environmental returns.

Some interesting facts from the EERE website –

Today, U.S. wind energy installations produce enough electricity on a typical day to power the equivalent of more than 9.7 million homes.

America’s wind power fleet will avoid an estimated 62 million tons of carbon dioxide annually, equivalent to taking 10.5 million cars off the road, and will conserve approximately 20 billion gallons of water annually, which would otherwise be consumed for steam or cooling in conventional power plants. Is that cool or what??

Over its life, a small residential wind turbine can offset approximately 1.2 tons of air pollutants and 200 tons of greenhouse gases, that is so Green!!

If you are thinking about installing a wind turbine I hope this article helped you. Live Green!!

Some more pages to read if interested:

1. EERE Wind
2. Bergey
3. American Wind Energy Association

How do Wind turbines work?

Wind Farm

Wind Farm

Simply put wind turbines convert kinetic energy from the rotating blades and turbines into electrical energy using a generator. There are two types of turbines in use one is horizontal (the 3 blade ones like propellers which we see more often) and the vertical ones (which are very very rare). Commercially the horizontal axis wind turbines are more widespread. The vertical axis ones are mostly used in smaller stand alone units and on off grid systems to pump water. The commercial turbines now available in the market vary between 1-4 MW output.

Continue reading