Wind power basics:

How do you calculate the Energy stored in the wind?:

Wind kinetic Energy is KEw = AirMass*WindSpeed^2/2

AirMass is defined by the AirVolume that flows through the wind turbine * AirDensity

AirVolume is defined by the TurbineArea*WindSpeed & AirDensity is roughly 1.3 kg/m3

TotalEnergy KEw= TurbineArea * WindSpeed^3 * AirDensity / 2

Wind Speed is completely dominating the available wind energy. How high is it then?

Average Wind Speed

Image show average annual wind speed in Stockholm, Sweden.

See: http://www.windfinder.com/

In Stockholm then we can assume the Average Wind speed to be 8 kts or 4 m/s

Which are the factors reducing the available average Wind Speed?

Altitude Dependent Wind Speed Reduction

The image show how the wind speed is changing with altitude and type of surrounding.

As an example the wind speed on a roof top is reduced by 30% compared to high level undisturbed wind.

Wind speed Reduction and Amplification Around Different Barriers

The physical placement of a Wind turbine is greatly affected by its surroundings.

Either the wind speed is reduced by trees or buildings or it can be amplified by different objects.

How much is lost when harvesting the energy in the Wind turbine?

Wind Turbine Peak Efficiency

Maximum theoretical Wind turbine efficiency is 59%

Efficiency for different solutions is displayed in the Image.

The dominant solution today is the HAWT with 2 ,3 or 4 blades.

+ So far the highest peak efficiency of about 47 %

+ Mature established technology with high competition

- Requires a lot of free space, sensitive to turbulence & has lifetime issues

- Not for households due to its estetic nature and the propeller generated infra sound noise levels of 30-40 db

Cost/w Small scale: 600 W for 3000 $ = 5 $/W

Cost/W large scale 45 kW for 80000$ = 1.8 $/W or 0.04 $/kWh

Average efficiency: 1kW equals roughly 2000 kWh/year

Technology Potential: Wind farms will be dominated by the HAWT for a long time with a cost/kWh soon at competitive levels if lifetime can be extended but it will not be a hit for households.

2. Rural windmill

A rural windmill like in old western movies providing water.

Multiple concave wing forces a slow rotation ideally suited for water pumps and other slow rotation applications.

+ Very low cost and simple production

+ Operates at low wind speeds.

- Low efficiency < 20%

- Not ideal for electricity production due to its low TSR

Technology potential: This is a low cost solution and may be a hit for low cost niche applications.

3. Darrieus Wind Turbine

Lift-Type Vertical Axis Wind Turbine

Instead of collecting the wind in cups dragging the turbine around, lift forces generated by the wind hit aerofoils to create rotation.

+ High Tip Speed Ratio, meaning fast rotation compared to wind speed makes it suitable for electricity generators

+ Simple construction and low forces on bearings

+ As high theoretic efficiency as the HAWT Propeller of 40 -45 %

- – Needs a push to start & breaks in a storm

Technology Potential: Very high potential due to its simplicity and high efficiency. However this may be a future solution for a long time due to practical issues connected to the start and high speed issues.

4. Giromill or H-Bar Wind Turbine

The Darrieus Variant with 2 or more vertical straight blades

Lift force generated rotation commonly on a vertical shaft

+ Decent theoretical efficiency 30-35%

+ Quite simple & low cost to build + Works well in high turbulence

- High forces on the structure

- Needs a push to start

Technology potential: This is already a big hit due to high performance/cost ratio however there is variant called the CycloTurbine that can twist the blades so that it can start in low wind which could be even better.

5. Savonius Wind Turbine

A drag type Vertical Axis Wind Turbine that uses the air to push the rotation.

Since it uses Drag the TSR, Tip Speed Ratio, is low < 1 but it works at low wind speeds and gives smooth rotation.

+ Works at low speeds and gives a smooth rotation even in storms

+ Very simple, robust and low cost construction

- Low TSR make it not ideal for electricity production.

- Low Efficiency at roughly 15 %

Cost Example: 36W @ 10 m/s @ 0.3 m2 for 500 $

Technology Potential: This technology has all the rights except for Low efficiency. New generators can probably handle the low TSR. This solution will be found in many future products.

6. Mag-Wind Vertical Axis Wind Turbine

An interesting combination of technologies with the aim of beeing discrete, self started, low cost and robust.

- Efficiency as a savonius engine of 15-20%

+ Discrete, robust, Low Cost & Self Started

+ Perfect for a roof top at urban homes to provide necessary household electric consumption.

See:http://www.enviro-energies.com/

Cost: 5 kW -> 12,5 k kWh/year for 25 k$

Technology potential: Huge! It is not as efficient as a Stuart mill but it could work in our homes where its price/performance is to its advantage.

New Creative Designs with Potential

7. FloDesign Jet engine Wind turbine

Jet engine technology based Wind turbine design.

See Video: http://www.youtube.com/watch?v=RagPPrHUMTY

Technology Potential: I guess if it is true what they say, the efficiency can be very high but there must be a cost and complexity issue.

8. WindSpire Wind Turbine

The Windspire is really nothing more than a slicker form of the older gyromill technology. Lift forced created rotation with 3 blades.

+ It is slicker and nicer looking which gives it an advantage of the classic Straight blade Gyromill.

+ Decent performance, COP of 30-30%

- It could be fragile even though the selling company says that it is not.

Cost: 5000$ for a system that produces 2000 kWh annually.

Technology potential: Same as the gyromill although the selling company has made a nice work productifying it for your back yard.

See: http://www.mariahpower.com/windspire-overview.aspx

9. WindPod Wind Turbine

The Australian inventor Graeme Attey has made himself quite a name in green business with this invention. It is a Savonius-gyromill combination that uses both lift and drag. It is shaped like a big tube 1 m long and 45 cm in diameter.

+ Could be on everybody’s roof tops in 10 years.

+ Very Low price/performance

+ Decent Efficiency of 30-35 percent and it self started.

- Has an optimal angle of the wind

Technology Potential: Of Course the potential is very high since it is slick, low cost and high efficient. All the rights except for the wind angle efficiency.

See Video:http://www.youtube.com/watch?v=WZ5kX5Yw4eY

10. Helix Wind Turbine

A Creative, savonius based, vertical axis wind turbine with a frame at the top and the bottom for a more rigid construction and elegantly designed.

+ Probably high endurance and quite nice to look at.

+ Low noise

- Efficiency. Produces 3500 kWh per year. Price 14500$

Technology potential: HelixWind corporation has understood the need for a slick design when going into urban locations. The design may be more important than efficiency for the targetet customers. It is however way to expensive for that output. Return on investment is 30 years.

Homepage: http://www.helixwind.com/en/S594.php

Video: http://www.youtube.com/watch?v=q9flSPAdOLk

11. HAWT made by wood

Optimization of the core Wind technologies will see many creative solutions. Making the HAWT in Wood is one of them and it is really interesting. The steel solutions up until today take damage in salty offshore conditions, the price for a wooden constuction is much lower and the complete life cycle environmental impact is greatly improved with this construction. The Tower comes in different shapes and can raise 200 meters above ground.

+ environmental friendly

+ Fast mounting

+ Wheather endurance

+ Low Cost/Performance

- Have not found any real minuses even though they need to prove lifetime (20 years garanteed).

Technology potential: If their lamination works out so that the life time is as great as they say this will most likely be a big hit on the market and we can send gratulations to the german company Timber Tower for having a bright future.

Link: http://www.timbertower.de/

Video: http://www.youtube.com/watch?v=MX2rngm2GC4&feature=player_embedded

Links:

http://www.designboom.com/weblog/cat/16/view/5308/wind-power-technology.html

http://www1.eere.energy.gov/windandhydro/wind_how.html

Authors Thoughts:

If a technology will make it to the big masses it has to fulfill the requirement that the business case it provides to the customers need to be excellent. Very few will invest in a green technology if the return on investment is too far off or if the sacrifice to normal standards is too high. There is also always a threshold to adapt new concepts which makes the financial aspect even more important.

As an example In Sweden the Air to Air inverter heat pumps has become very popular to provide low cost heat. Why? Because in many households the return on investment is less than 2 years.

In Sweden also the pumps from geothermal heating has become popular although they are very expensive. Why? Because at the same time it gives you cheap and nice energy it increases the market value of your home.

I believe that harvesting Energy from the wind is VERY competitive and in 50 years this market will be huge. There will be room for both large scale plants to small building solutions. There is soo! many yet undiscovered business cases to be made in the wind power industry. Price/performance is everything and new innovations must focus on lower cost and improved average wind speed solutions to make nice green low cost kWh.

This post will be continuously updated with the summary of the most relevant and promising wind power technologies.

The post Technology solutions for wind power generated electricity appeared first on Green Energy Reporter.

Since it’s founding in 2009 Green Energy Reporter has published nearly 2,000 articles chronicling the most important developments in the North American renewable energy industry.

We are proud to have brought our readers exclusive, actionable market

intelligence for over two years. However, given the continuing challenges affecting this sector, we have made the difficult decision to suspend daily publication.

Today renewables are an essential source of energy, and their share of the North

American energy supply will continue to grow in the coming years. We at G.E.R.

recognize that market conditions are always changing, and we hope that they will

change in a way that will allow us to resume our coverage of green energy finance and policy.

Over the last few years we have truly been honored by your continued readership, and we hope to reconnect with you in the future.

Please contact us by email at editors@greenenergyreporter.com if you have any

comments or questions.

Best regards,

Terrence Murray and Mark Pabst

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Solar Thermal Technologies

What dominating technology will play the largest part in the solution of providing clean energy in the future?

Well the answer is that it stands between a handful of technologies where large scale or utility scale solar thermal generated electricity might be the winner.

A more detailed update of the companies active in the utility scale solar power area is found here

There are many estimations made that say that solar power generated electricity will see a tight competition between photovoltaics and solar thermal where the arguments for photovoltaics usually are:

• Faster getting down in cost due to faster volume ramp including China and improved production techniques
• Concentrated Photovoltaics is moving fast to lower the amount of neccesary silicon and thereby cost.
• All PV technologies are pushing performance, Silicon PV, Thin Film CIGS, CdTe, CIS and AmSi are quickly improving their performance.
• More modular and the infrastructure supports using photovoltaics from the best sub contractor.
• Easier to install and lower maintenance cost

The arguments for solar thermal is usually:

• Higher quality of the produced electricity (Less abrupt spikes from clouds blocking the sun)
• Some of the technologies can store thermal energy to be used when the sun is blocked. Lots of research here to lower cost of the storage solution.
• Ability to capture a larger part of the solar light spectrum like infra red, enables higher efficiency.
• The high temperatures that are used to produce steam for the Concentrated solar power turbines can be achieved with a secondary plant based on natural gas or other biofuels and can be used during night and in the winter as backup.

I guess we will see in 50 years but the large scale solar thermal market is expected to grow roughly by a factor of 40 between 2009 and 2014 and that is not bad.

Here are 5 different Solar Thermal Electricity generating technologies:

1. Solar Tower with updraft wind Turbine

Solar Thermal – Updraft Wind Turbine

Solar Tower functionality description

Principle of operation:
Heated air is generated below the glass shield covering the ground. The heated Air travels, by convection, up through the large chimney where wind turbines generates the electricity.

Technology strenghts:
+ Low cost to cover the ground with glass.
+ The moving media (ie the upward air) is moving through a limited area where turbines can work in a very efficient way.

Technology threats:
- Requires a very tall chimney
- How do you maintain a turbine within this tower??

Technology Potential:
Probably very robust way of large scale solar thermal generated electricity where these types of towers are allowed.

Links:
The Australia project: http://www.enviromission.com.au/EVM/content/home.html

Companies active in the solar updraft tower area is found here

2. CSP Solar Power Tower

BrightSource Solar Thermal Power Tower

Principle of operation:
This solution is all about maximizing the efficiency from thermal energy to electrical energy (Rankine cycle efficiency).

• Two dimensional moving mirrors, or heliostats, focuses the sunlight roughly 500 times toward a receiver, containing a working fluid, recently molten salt, located close to the top of the turbine tower.
• Water is pressurized by a pump from 0,02 Bar to 100 Bar to prepared for the boiler
• The working fluid driven boiler or evaporator generates dry 550 C steam of the high pressure water to drive the steam turbine which generates the electricity.
• The lower pressure and lower temperature steam is condensed back to water in a condenser.
• Thermal energy is stored in a molten salt(a mix of sodium and potassium nitrate) container to be used when the sun is not shining. As a reference a 9 m high and 25 m in diameter molten salt container drives a 100 MW turbine for 4 hours.

Technology strengths:
+ The medium heated during the day can be stored in vessels to keep the turbines running at night to perhaps if the storage cost is reduced, produce electricity 24/7.
+ They claimed earlier to achieve the highest Efficiency.
+ High boiling temperature and small relative receiver area together with large scale turbines enables good price/performance for large scale plants.
+ Lots of research ongoing of lower cost/ high quality mirrors that will also scale with volume.
+ Requires less water than Parabolic trough

Technology threats:
- The mirror cost itself + 2d axis movement and syncronisation of mirrors need to get down in cost.
- There are some safety concerns with reflections from the tower and there are also some environmental concerns regarding bird life and highly concentrated light.
- Will the storage solutions ever get down in cost so that electricity can be produced 24/7?

Technology potential:
This is already becoming a large scale technology and it has had its breakthrough. Success gives volume and then the expensive 2 axis mirrors and the storage solution could be cheap enough.

Links:
http://www.brightsourceenergy.com/technology

Companies active in the CSP Solar power tower area is found here

3. Parabolic trough CSP

Parabolic trough solar thermal power plant

Andasol 1: Parabolic trough power plant

Parabolic Trough Functionality Description

Principle of operation:
A parabolic reflector is used to concentrate sunlight on an insulated tube (Dewar tube) or heat pipe, placed at the focal point, containing coolant which transfers heat from the collectors to the boilers in the power station. The world’s largest parabolic trough facilities, located in the Mojave Desert, consist of nine plants producing 354 megawatts of power at peak output.

Technology strengths:
+ Parabolic trough power plants are the only technology for utilizing solar energy in large power plants that has been commercially proven over a number of years
+ Simple & robust technology
+ Probably still the lowest price/performance of the large scale thermal solutions, especially when looking at maintenance cost and life time.
+ Can easily be combined with other sources electricity production, like natural gas, during cloudy days to produce electricity 24/7

Technology potential:
Likely to be one of the big electricity generating technologies for the future.

Companies using the parabolic trough solution is found here

4. Concentrating Linear Fresnell reflector (CLFR)

One dimensional moving flat deflector for solar thermal electricity

Principle of Operation:
The Compact Linear Fresnel Reflector (CLFR) solar collector and steam generation system, uses linear flat reflector mirrors to focus the sun’s heat onto elevated receivers, which consist of a system of tubes containing the heated working fluid. Some solutions use water directly as the working fluid to reduce complexity and a heat exchange step.
The working fluid boils pressurized water in the boiler or evaporator, generating high-pressure steam for producing electricity by the turbine.

CLFR Optical principle

Technology strenghts:

• Claims to be one of few to use water as a working fluid and that it is animal safe .
• Mirrors are said to be cheaper than parabolic trough due to the flat design.
• Easier to maintain and less efficiency reduced shading compared to Parabolic trough due to its flat construction.

Technology threats:

• A more complex and potentially more expensive solution compared to parabolic trough
• Does the same thing as parabolic trough and parabolic trough was there first and already have volumes.

Technology potential:
As large as the conventional parabolic trough technology.

Companies using the CLFR solution is found here

5. Two dimensional parabolic dish solar thermal collector or Stirling dish

2D parabolic dish solar thermal plant

Parabolic dish system

Principle of operation:
Parabolic dish concentrators are similar to trough concentrators, but focus the sunlight on a single point. Dishes can produce much higher temperatures and the small focal heating area reduces the thermal radiation loss, and so, in principle, should produce electricity more efficiently. This technology have not yet had its big breakthrough due to its higher complexity but recent use of the Stirling engine have increased the efficiency and perhaps lowered the price/performance.
More info of the Stirling dish system technology can be found here

Technology strengths:

• A modular solution providing very high temperatures in a small low thermal radiation area enables a high rankine cycle efficiency and solar irradiation collector efficiency.
• Requires no water which is a big advantage in the desert
• Combine the dish with a sterling engine in the focal point and you get the highest efficiency so far with a record of 32%

Technology threats:

• Complexity and cost (At least initially)
• Same limitations as photovoltaics with uneven production and no energy storage to produce electricity during night
• Why did Tessera solar loose lately?

Companies using the Parabolic dish or Sterling solution is found here

Companies within large scale Solar Power Generation

Photovoltaics:

• SunPower Corporation
• First Solar
• Sharp Solar
• SunEdison Solar Electricity
• Neo Solar Power Corporation
• Abound Solar
• SunTech Solar

Concentrated Photovoltaics:

• SolFocus
• Whitfield Solar
• Amonix
• Circadian Solar
• Concentrix Solar

Parabolic dish concentrating photovoltaics

• Solar Systems

CSP Solar Power Tower

• BrightSource Energy
• eSolar

CSP Fresnel Reflectors

• AREVA (Former Ausra)

CSP Parabolic Trough

• Siemens (Aqquired Solel Solar Syatems and Archimede)
• ACCIONA Energy
• Solar Millennium AG
• Solar Trust of America
• Capital Sun Group

CSP Sterling dish

• Tessera Solar
• Stirling Energy Systems

Micro CSP

• Sopogy Micro CSP

List of current and ongoing Solar Power Plants in the world can be found here

The post Solar Thermal generated electricity – Future dominating technology? appeared first on Green Energy Reporter.

The suspension, NRG said, would impact the Mid-Atlantic Wind Park, a 200-megawatt projects slated for construction off the coast of Delaware.

NRG, which acquired the Mid-Atlantic project as part of its 2009 buyout of New Jersey developer Bluewater Wind, said it’s been forced to scale down its offshore ambitions because it was unable to find a partner to help finance Mid-Atlantic and other projects. The company also blamed the overall regulatory uncertainty and a lack of subsidies. All of these factors made the project unfinanceable and financially untenable, the company said.

NRG said it had terminated the long-term PPA it had signed with Delmarva Power & Light Co., back in 2008.

Despite a deep offshore potential, the U.S. has so far been unable to build a single project. Cape Wind, the country’s pioneering developer of a 486-megawatt project in Massachusetts, has been trying to get an offtaker for half of its unsold output for years and can’t launch construction until it has secured this second PPA. In 2010 National Grid said it would buy half of Cape Wind’s output.

When NRG acquired Bluewater, in 2009,  the outlook for offshore wind was much more positive. The Obama administration had clearly stated that it wanted to populate the U.S. coasts with large wind farms. This political goodwill helped Bluewater receive preferential development rights for a project it was developing off the coast of New Jersey. The project was inline to get a Department of Energy Loan Guarantee.

A little more than two years later, with DOE loan guarantees no longer available and investment and production tax credits not extended, the outlook for U.S. offshore is bleak.

Its seems Bluewater founder, Peter Mandelstam, which two years ago engineered the sale to NRG, hasn’t given up on the Delaware project or on any of his other projects. Trade publication North American Windpower reports that he has been out in Europe, scouting for investors to take over Bluewater’s project pipeline.

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Under its revised guidance, First Solar expects 2011 net sales to range between $2.8 billion and $2.9 billion, down from an initial range  of $3.0 to $3.3 billion. Next year, First Solar forecasts net sales of  $3.7 to   $4.0 billion. According to Bloomberg the company had expected 2012  revenues of $4.06 billion.

The earnings’ cut reflects the challenging market conditions faced by Western solar panel makers, which are competing with a flood of cheap Chinese panels. Specific to  First Solar, overproduction has also  cut into the Arizona company’s revenues. To reverse the situation, last month, First Solar founder Michael Ahearn rejoined the company as interim CEO, replacing Robert Gillette, a former executive with Honeywell International’s aerospace division, who had joined the company three years earlier.

In a prepared statement First Solar’s Ahearn said the company was recalibrating its business “to focus on building and serving sustainable markets rather than pursuing subsidized markets.” He  also remains optimistic about his company’s long-term success. “Our diverse business model and robust project pipeline will help First Solar generate a significant amount of cash in 2012 while improving operational efficiencies,” Ahearn explained.

While these lower costs have helped push solar generation closer to grid parity, it’s also forced a number of capital-intensive solar companies to shutdown. Just this year EverGreen Solar, Solyndra and SpectraWatt all filed for bankruptcy protection, and  on Wednesday the tough market conditions pushed solar module company Solon to seek creditor protection, reports GreenTechMedia.

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First Reserve is putting $150 million of its own equity in the venture, writes Reuters, which first reported the news. Fully developed First Reserve and Renovalia could invest as much as $1 billion.

The First Reserve investment comes as project finance banks, pressed by the European debt crisis, are tightening lending, forcing renewable energy developers to secure new sources of capital to finance their projects. Also, in the U.S. the end of some key subsidies, has wrapped the local industry  in uncertainty. This challenging climate hasn’t stopped large, PE investors, including First Reserve, to invest in the sector, attracted by the long-term, stable returns generated by contracted wind and solar farms.

Renovalia oversees 295 megawatts of operating wind-powered capacity, largely in Europe. In the U.S., Canada and Mexico Renovalia has a 494-megawatt project pipeline.

First Reserve is invested in solar developer 9Ren New Energies Group, formerly Gamesa Solar. First Reserve also holds a stake in the 70-megawatt Rovigo solar PV power plant.

We’ve reached out to First Reserve for more details.

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The navy will buy a biofuel blend made from non-food waste distilled by Louisiana-based Dynamic Fuels, which is jointly-owned by Tyson Foods and Solazyme unit, Syntroleum Corporation.

The deal is part of the Obama’s administration’s $510 million, three-year investment program to advance the development and deployment of drop-in biofuels to substitute conventional, carbon-based diesel and jet fuel. The Agriculture, Energy, and Navy departments oversee the program.

The purchase, which still has to be approved by Congress, could act as a catalyst that could speedup the commercialization of next-generation biofuels.

“In March, the President challenged me, Secretary Mabus, and Secretary Steven Chu to work with the private sector to cultivate a competitively-priced—and domestically produced—drop-in biofuel industry that can power not just fighter jets, but also trucks and commercial airliners,” said Agriculture Secretary  Tom Vilsack. Dynamic Fuels’ Andy Rojeski added: “This contract clearly demonstrates that we’re building momentum for the continued commercialization of advanced renewable fuels production here in the U.S.”

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The Los Angeles company, pressed by a tightening credit market, has stopped the development of its wholly-owned, 55 megawatts, $225 million, Port Saint Joseph biomass project in Florida. This was one of the company’s signature initiative and is the third project axed by Rentech. The company blamed the Saint Joe shutdown on its inability to secure “private financing on acceptable terms.”

Until this summer Rentech had been counting on a Department of Energy Loan Guarantee to finance part of Saint Joe. However, earlier this summer, the DOE effectively turned down Rentech’s loan application.

To make up for the DOE money Rentech turned to a group of unnamed private funders but was not able to strike a deal with them. Those talks coincided with the European debt crisis, which over the past weeks has pushed banks to tighten lending, increasing overall cost of funds.

The overall tough funding climate has forced Rentech to significantly slim down its project pipeline. In October the company stopped the development of its 1,500 barels per day Rialto biofuel refinery in California. It also halted development work supporting a  30,000 barrels per day coal-to-synthetic fuel refinery in Natchez, Miss.

Rentech will book a $4.8 million charge because of the Saint Joe shutdown. Combined, the closing of the Saint Joe, Rialto and Natchez projects will generate up to $60 million in non-cash impairment charges, the company said.

Rentech is not totally walking away from project development. The company recently completed a $59 million demonstration syngas plant in Colorado. The government funded facility is expected to go live by year-end.

Earlier this month Rentech’s, Rentech Nitrogen Partners, a manufacturer and marketer of nitrogen fertilizer products, raised more than $136 million in an Initial Public Offering.

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