Department of Small Wind and Pico Hydel Energy

Objective:

  • To assess the performance of micro Winds turbines at various locations and heights
  • To assess the performance of Solar –Wind hybrid system in various seasons
  • To assess the performance of various models of micro Wind turbines
  • To popularize various models of pico hydal systems with innovative applications at various locations

Faculty:

         Sri. Ravi .K, Deputy Director (Small Wind and Hydro)
         Sri. M.R. Aravind, Assistant Director (Small Wind and Hydro)

Areas of research:

  • Pico Hydro Power Generation from Sewage Water
  • Pico Hydro Power Generation from Canal Water
  • Portable Small Wind and Solar Hybrid System

Consultancy :

  • Wind Potential Assessment
  • Electrification of unelectrified areas through wind solar hybrid & picohydro

Subjects:

Societies have taken advantage of wind power for thousands of years. The first known use was in 5000 BC when people used sails to navigate the Nile River. Persians had already been using windmills for 400 years by 900 AD in order to pump water and grind grain. Windmills may have even been developed in China before 1 AD, but the earliest written documentation comes from 1219. Cretans were using "literally hundreds of sail-rotor windmills to pump water for crops and livestock".

 

The Windmill
Wind EnergyThe Dutch were responsible for many refinements of the windmill, primarily for pumping excess water off land that was flooded. As early as 1390, they had connected the mill to "a multi-story tower, with separate floors devoted to grinding grain, removing chaff, storing grain, and (on the bottom) living quarters for the windsmith and his family." Its popularity spread to the point that there were 10,000 windmills in England. But perfecting the windmill's efficiency to the point that it "had all the major features recognized by modern designers as being crucial to the performance of modern wind turbine blades" took almost 500 years. By then, applications ranged from saw-milling timber to processing spices, tobacco, cocoa, paints, and dyes.
The windmill was further refined in the late 19th century in the US; some designs from that period are still in use today. Heavy, inefficient wooden blades were replaced by lighter, faster steel blades around 1870. Over the next century, more than six million small windmills were erected in the US in order to aid in watering livestock and supplying homes with water during the development of the West. The first large windmill to produce electricity was the "American multi-blade design," built in 1888. Its 12-kilowatt capabilities were later superseded by modern 70-100 kilowatt wind turbines.

Physics of Wind turbines
For all wind turbines, wind power is proportional to wind speed cubed. Wind energy is the kinetic energy of the moving air. The kinetic energy of a mass m with the velocity v is


The air mass m can be determined from the air density ρ and the air volume V according to


Then,


Power is energy divided by time. In small time, Δt, in which the air particles travel a distance s = v Δto flow through. We multiply the distance with the rotor area of the wind turbine, A, resulting in a volume of


which drives the wind turbine for the small period of time. Then the wind power is given  as



The wind power increases with the cube of the wind speed. In other words: doubling the wind speed gives eight times the wind power. Therefore, the selection of a "windy" location is very important for a wind turbine.The effective usable wind power is less than indicated by the above equation. The wind speed behind the wind turbine cannot be zero, since no air could follow. Therefore, only a part of the kinetic energy can be extracted. Consider the following picture:

 
The wind speed before the wind turbine is larger than after. Because the mass flow must be continuous, the area A2 after the wind turbine is bigger than the area A1 before. The effective power is the difference between the two wind powers:



If the difference of both speeds is zero, it will have no net efficiency. If the difference is too big, the air flow through the rotor is hindered too much. The power coefficient cp characterizes the relative drawing power:



To derive the above equation, the following was assumed: A1v1 = A2v2 = A (v1+v2) / 2. It is designate the ratio v2/v1 on the right side of the equation with x. To find the value of x that gives the maximum value of CP, we take the derivative with respect to x and set it equal to zero. This gives a maximum when x = 1/3. Maximum drawing power is then obtained for v2 = v1 / 3, and the ideal power coefficient is given by


TYPES OF WIND TURBINE

There are two types of wind turbines. One is Vertical axis wind turbines and the other is horizontal axis wind turbines. We know that there is enough wind globally to satisfy much, or even most, of humanity’s energy requirements – if it could be harvested effectively and on a large enough scale.

Vertical Axis Wind Turbines
Vertical axis wind turbines (VAWTs), which may be as efficient as current horizontal axis systems, might be practical, simpler and significantly cheaper to build and maintain than horizontal axis wind turbines(HAWTs). They also have other inherent advantages, such as they are always facing the wind, which might make them a significant player in our quest for cheaper, cleaner renewable sources of electricity. VAWTs might even be critical in mitigating grid interconnect stability and reliability issues currently facing electricity producers and suppliers. Additionally, cheap VAWT’s may provide an alternative to the rain forest destruction for the growing of bio-fuel crops.


Vertical axis wind turbines (VAWTs) in addition to being simpler and cheaper to build have the following advantages:
  • They are always facing the wind – no need for steering into the wind.
  • Have greater surface area for energy capture – can be many times greater.
  • Are more efficient in gusty winds – already facing the gust
  • Can be installed in more locations – on roofs, along highways, in parking lots.
  • Do not kill birds and wild – life – slow moving and highly visible.
  • Can be scaled more easily – from milliwatts to megawatts.
  • Can be significantly less expensive to build – are inherently simpler.
  • Can have low maintenance downtime – mechanisms at or near ground level
  • Produce less noise – low speed means less noise
  • Are more esthetically pleasing – to some one.

Horizontal Axis Wind Turbines
Horizontal-axis wind turbines (HAWT) have the main rotor shaft and electrical generator at the top of a tower, and may be pointed into or out of the wind. Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a servo motor. Most have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive an electrical generator.


HAWT Advantages

  • Variable blade pitch, which gives the turbine blades the optimum angle of attack. Allowing the angle of attack to be remotely adjusted gives greater control, so the turbine collects the maximum amount of wind energy for the time of day and season.
  • The tall tower base allows access to stronger wind in sites with wind shear. In some wind shear sites, every ten meters up, the wind speed can increase by 20% and the power output by 34%.
  • High efficiency, since the blades always moves perpendicularly to the wind, receiving power through the whole rotation. In contrast, all vertical axis wind turbines, and most proposed airborne wind turbine designs, involve various types of reciprocating actions, requiring airfoil surfaces to backtrack against the wind for part of the cycle. Backtracking against the wind leads to inherently lower efficiency.
HAWT Disadvantages
  • The tall towers and blades up to 90 meters long are difficult to transport. Transportation can now cost 20% of equipment costs.
  • Tall HAWTs are difficult to install, needing very tall and expensive cranes and skilled operators.
  • Massive tower construction is required to support the heavy blades, gearbox, and generator.
  • Reflections from tall HAWTs may affect side lobes of radar installations creating signal clutter, although filtering can suppress it.
  • Their height makes them obtrusively visible across large areas, disrupting the appearance of the landscape and sometimes creating local opposition.
  • Downwind variants suffer from fatigue and structural failure caused by turbulence when a blade passes through the tower’s wind shadow (for this reason, the majority of HAWTs use an upwind design, with the rotor facing the wind in front of the tower).
  • HAWTs require an additional yaw control mechanism to turn the blades toward the wind.
(Source-The Case for Vertical Axis Wind Turbines Terrence C. Sankar, Robert Morris University, Pittsburgh)

Wind Turbines That Push the Limits of Design
The company, WhalePower, has redesigned the typically smooth blades on a turbine, adding a series of ridges, based on tubercles, the bumps on humpback whale fins. The company says this new blade design could increase annual electrical production for existing wind farms by 20 percent.


The qr5 wind turbine is designed for an urban environment with low wind speeds and changing wind directions.




Windspire is a vertical wind turbine, similar to the Quiet Revolution. This 30-foot tall, 4-foot wide turbine generates 2000 kilowatts per hour given 12-mph winds, and it can survive winds up to 105 mph.



MARS is a high-altitude wind turbine that stays afloat with a helium-filled, airship-like body. It can be tethered up to 1000 feet in the air. MARS rotates around a horizontal axis as the wind hits fins along the side. The rotation generates electricity, which is transferred down the power line, which doubles as its tether, to the ground.

The Windbelt, created by PM Breakthrough Award Winner, Shawn Frayne, is a small-scale wind turbine that can generate 40 milliwatts in 10-mph winds and only costs a couple of dollars. The goal is to help the poor power their lights cheaply and safely.
A pair of magnets fitted on a membrane oscillate between two wire coils to generate electricity.

 
Honeywell is a rooftop wind turbine that works in wind speeds as low as 2 miles per hour.
The Honeywell turbine does not have gears like traditional wind turbines. Instead, it creates power from magnets in its blade tips and in the enclosure for the blades. This, claims Honeywell, results in lower resistance, which can mean higher energy output.
 
WePOWER is a vertical-axis wind turbine that operates quietly and performs well in low-speed winds.
Unlike many turbines, which either rely solely on lift (in the case of traditional three-blade turbines) or drag (used in wind-speed gauge anemometers), WePOWER uses a combination of both. Its unique airfoil lets it produce power at low wind speeds.
 
Architectural Wind is a small wind turbine that can be mounted on the top edge of a building.
When wind hits a building, the resistance creates an area of accelerated air flow--straight up the side of the building. This wind turbine catches the faster winds as they travel up the wall.
 
The Sky Serpent makes use of multiple rotors attached to a single generator.
Past multirotor turbines have run into trouble because their rotors just catch the wind generated by the spin of neighboring rotors. The Sky Serpent's rotors are spaced and angled to ensure that each one is catching fresh wind.
 
This vertical axis turbine uses drag propulsion to push the blade that is designed as an involute spiral.
The turbine uses aluminum vanes formed into an involute spiral--giving the blade extremely high surface area--to capture wind and rotate.
 
Total Renewable Energy Installed Capacity (May 2014)

Source Total Installed Capacity (MW)
Wind Power
21,262.23
Solar Power (SPV)
2,647.00
Small Hydro Power
3,803.65
Biomass Power
1,365.20
Bagasse Cogeneration
2,512.88
Waste to Power
106.58
Total
31,833.01
 

Wind Energy Sources
Today, people are realizing that wind power "is one of the most promising new energy sources" that can serve as an alternative to fossil fuel-generated electricity.

As of December 2013 the installed capacity of wind power in India was 20149.50 MW, mainly spread across Tamil Nadu (7162.18 MW), Maharashtra (3021.85 MW), Gujarat (3174.58 MW), Karnataka (2135.50 MW), Rajasthan (2684.65 MW), Madhya Pradesh (386.00 MW), Andhra Pradesh (447.65 MW), Kerala (35.10 MW), West Bengal (1.10 MW), other states (3.20 MW)  It is estimated that 6,000 MW of additional wind power capacity will be installed in India by 2012. Wind power accounts for 6% of India's total installed power capacity, and it generates 1.6% of the country's power. In its 12th Five Year Plan (2012-2017), the Indian Government has set a target of adding 18.5 GW of renewable energy sources to the generation mix out of which 11 GW is Wind Energy.

Wind Turbine Size
Wind turbine size and power generation capacity grown in last three decades is shown below.


 
Present World Biggest Wind Turbines

1) SeaTitan 10MW Wind Turbine
The SeaTitan™ 10MW wind turbine designed by American energy technologies company AMSC is currently the biggest wind turbine in the world. The direct-drive turbine, with 190m rotor diameter, has a rated power capacity of 10MW and hub height of 125m. AMSC started developing the turbine in 2010 and completed the design in 2012. The generator for the wind turbine has been tested by the US Navy in harsh offshore conditions. AMSC is currently negotiating with potential partners to build and commercialise the SeaTitan 10MW wind turbines.

2) Sway Turbine ST10
The ST10 offshore wind turbine designed and developed by the Norwegian technology company Sway, is the world's second biggest wind turbine. It has a power output of 10MW, is equipped with a rotor of 164m diameter, and has a 2rpm nominal speed and blades 67m in length. The turbine was developed between 2005 and 2012 with an investment of €20m ($27.4m), and is suitable for both fixed and floating foundations. Sway Turbine is looking for potential partners to commercialise the ST10 turbine technology.
(Besides AMSC and SWAY, Mitsubishi and Sinovel are also reportedly developing 10MW wind turbines, the details of these turbine designs have not however been revealed.)

3) Areva 8MW wind turbine
French energy company Areva's 8MW wind turbine, launched in November 2013, is the world's third biggest wind turbine by rated capacity. The three blade offshore turbine, featuring 180m diameter rotor and a medium-speed hybrid gearbox, produces up to 8MW of power in an average wind speed of 12m/s. The turbine design is based on Areva's M5000 series wind turbines installed at the Global Tech I and Borkum West II offshore wind farms in Germany. The turbine's prototype is scheduled to be installed in 2015, while commercial production is expected to begin in 2018.

4) Vestas V164-8.0 MW
The Vestas V164-8.0 MW, with a rated capacity of 8MW and rotor diameter of 164m, is currently the fourth biggest wind turbine in the world. The turbine is designed for offshore operation and offers a swept area of more than 21,000m². Each of the three blades of the turbine is 80m long and weighs 35t. The nominal rotor speed of the turbine is 10.5rpm.

5) Enercon E-126/7.5 MW
The Enercon E-126/7.5 MW wind turbine, launched by the German company Enercon in 2007, is the world's fifth biggest wind turbine. The 7.5MW gear-less turbine has a hub height of 135m, a 127m diameter rotor, and provides a swept area of 12,668m². The rotational speed of the upwind rotor with active pitch control varies between 5rpm and 11.7rpm. The turbines are operational at Magdeburg-Rothensee and Ellern onshore wind farms in Germany, and the Estinnes onshore wind farm in Wallonia, Belgium. Noordoostpolder onshore wind farm in the Netherlands will also use Enercon E-126/7.5 MW wind turbines.

6) Samsung S7.0-171
The Samsung S7.0-171 wind turbine, developed by Samsung Heavy Industries, is the sixth biggest wind turbine in the world. The offshore wind turbine has a rotor diameter of 171m and rated power capacity of 7MW. The swept area of the turbine is 23,020m² and hub height is 110m. Each of the three blades of the turbine is 83.5m long.A prototype of the Samsung S7.0-171 was installed in the Fife Energy Park off the coast of Scotland in 2013. Commercial availability of the 7MW wind turbine is expected in 2015.
REpower 6.2M152 / REpower 6.2M126

7) REpower 6.2M126 & 6.2M152

The 6.2M126 and 6.2M152 wind turbines, developed by the Suzlon group company Repower, are the seventh biggest wind turbines in the world. They are the latest in REpower's 6.XM series and have a rotor diameter of 152m and 226m respectively. Both the turbines have a rated power output capacity of 6.2MW.
The prototype of the REpower 6.2M152 turbine with 124m hub height is planned to be constructed at an onshore site in northern Germany by 2014.
Commercial production of the turbine is expected in 2015. REpower 6.2M126 wind turbines are already in use at Westre onshore wind farm in Germany, Vlissingen and Westereems onshore wind farms in the Netherlands, and Thornton Bank II offshore wind farm in Belgium.

8) Siemens SWT-6.0-154

The 6MW gearless offshore wind turbine Siemens 6.0 MW-154 is the eighth biggest wind turbine in the world currently. The turbine has 75m long blades and rotor diameter of 154m providing a swept area of 18,600m². Three new units of the Siemens SWT-6.0-154 wind turbines were installed at Hunterston test site of the UK-based utility SSE in October 2013.

9) Haliade 150-6MW wind turbine
Alstom's Haliade 150-6MW wind turbine, with 150m rotor diameter and 6MW rated power capacity, is the world's ninth biggest wind turbine.The blade length of the upwind wind turbine is 73.5m and the swept area is 17,860m². The rotor speed ranges between 4rpm and 11.5rpm. The turbine is suitable for operation in both offshore and onshore sites. The prototype of the Haliade 150-6MW wind turbine produced first power at an onshore site near Nantes in West France in July 2012 during its certification programme. A second prototype was installed at the Belwind wind park located 45km off the coast of Ostend, Belgium, in November 2013.

10) Sinovel SL6000
China's largest turbine manufacturer Sinovel designed and developed the world's tenth biggest wind turbine, the SL6000 6MW. The 6MW offshore wind turbine has a 128m diameter rotor and offers a swept area of 12,868m². It is the first 6MW wind turbine in China to be independently developed by a domestic company.The Sinovel SL6000 is an advanced version of the Sinovel SL5000. The first testing unit of the Sinovel SL6000 6MW was installed in Sheyang, in the Jiangsu Province of East China, in October 2011.

Pico Hydel Energy

To fulfill the Sampoorna Grameena Abhivruddhi dream of our Father of Nation and to achieve the energy independence dream of our former president, we need to give more thrust on development of renewable energy which is decentralized and more reliable. To save the earth from environmental disaster and also to tackle the energy crises development of renewable energy is the best solution. Renewable energy is green energy, environmental friendly, and they are the part of solution in energy conservation. Small hydro is also one among renewable energy sources.

Water is white coal which produces energy without any pollution and this coal does not require any firing time hence the generator can be started instantaneously without burning or firing action and thereby no addition of Carbon, Sox, and Nox etc. Hence Small Hydro Projects are Green Energy Projects.

Pico Hydro: Small Hydro Power is the part of renewable source of energy as it only uses and doesn't consume water for generation of electricity. Further, it is more environment and eco friendly than conventional hydro project and does not involve in setting up of large dams associated with problems of deforestation, submergence or rehabilitation and least impact on flora and fauna (aquatic and terrestrial).

A micro or mini hydropower station can divert only potential energy of the water which would have dissipated to no benefit in the natural flow along the water course. The domain where these can have potential impact on development is domestic lighting and stationery motive power demand for such diverse productive uses as water pumping, wood and metal work, grain mills, agro processing industries, etc' Those hydro projects which are defined under renewable energy, have an advantage of decentralized power supply. The disadvantages of associated with large hydro power plants, like transmission cost, environmental issues like submergence of forest and agricultural lands, and displacement of families, are not present. Moreover, the harnessing of local resources like Pico hydro projects being of a decentralized nature, lends itself to decentralized utilization, local implementation and management, making rural development possible based on self reliance and use of local natural resources.

Hydro Project Classification of Hydropower Plant

Power Class
> 10 MW Large
< 10 MW Small
< 1 MW Mini
<100 kW Micro
< 5 kW Pico
 

Small Hydro Potential in India
Estimated potential - 15,000MW
Commissioned as on date - 2013.17MW

Small Hydro Potential in Karnataka
Estimated potential - 2,500 MW
Allotted Capacity - 1937.45 MW
Commissioned as on date - 396.00 MW

Classification of SHPs based on head:
a) Low Head plant < 15 m.
b) Medium Head plant 15m < H < 50m
c) High Head plant H > 50m

Micro hydro power is the small-scale harnessing of energy from falling water. Hydraulic power can be captured wherever a flow of water falls. The vertical fall of water, known as the “head”, is essential for hydropower generation (fast-flowing water on its own does not contain sufficient energy for useful power production). Hence, two quantities are required for production of hydropower: a Flow Rate(volume,Q) of water and a Head(H). These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without purchase of fuel.Micro hydro systems complement photovoltaic solar energy systems, because in many areas, water flow, and thus available hydro power, is highest in the winter when solar energy is at a minimum

Power Potential is the product of available head and quantity of water at any point of time
P = 9.81Â x Q x h x n
P = Power in kW
Q = discharge in cum. m. per sec.
H = Net head in meters
n = overall unit efficiency (0.85to 0.9)

Advantages of SHP
1)    SHP s are encouraged because they are Eco friendly.
2)     SHPs are locally placed hence employment potential for local people.
3)     Decentralised power. (Minimises the T&D losses.)
4)    Development of infrastructure in rural area.
5)      No rehabilitation and displacement.
6)      It is green power.
7)      Nation gets the Carbon credit.
8)      By use of small hydro the water resources in major Reservoirs are conserved.
9)      Minimum submergence.
10)      Flora and Fauna of the nature is not disturbed.

Since it has become an attractive business for IPPs, states get power without any exchequer from its budget