How Turning Wind into ValueHow Turning Wind into Valuesebastiendufour.fr.free.fr/docs/wind.pdfsources are limited and may not meet the growing needs of the population. However, they

sources are limited and may

not meet the growing needs

of the population. However,

they are sufficient for their

burning triggers a danger-

ous climate disruption to

the planet.

The Energy problemThe Energy problemThe Energy problemThe Energy problem

Fossil fuels are still widely

used in the world today and

this can cause two main

problems: their rarities will

create geopolitical tensions

in the world and high emis-

sions of CO2 they generate

contribute heavily to global

warming. The availability of

reserves is a major source of

concern. At current rates of

consumption, oil will be the

first fossil fuel which we

should dispense, there

would be between forty and

sixty years of reserves. Natu-

ral gas could, in turn, be

exploited for another sev-

enty years.

The

growth

solicits

since the

beginning

of the in-

dustrial

age an

increasing

demand

for energy.

According

to the International Energy

Agency (IEA), global energy

demand could increase by

more than 50% by 2030. It

is estimated that by 2030

fossil fuels would still repre-

sent nearly 80% of our con-

sumption. Fossil energy re-

Wind EnergyWind EnergyWind EnergyWind Energy

Wind is the flow of gases on a large scale, it is driven by a pressure difference caused by

the differential heating between the equator and the poles and the Coriolis Effect. Gener-ally, wind is Polar maritime air masses that travel over the oceans. Human have used wind power to produce mechanical energy for a long time, but the efficiency of wind power engines has significantly increased with the wind turbine. The power in the wind is estimated in using a Rayleigh distribution, but the velocity is not the unique parameter which influence the wind power, the density of dry air, which change with the air tempera-ture and its molecular content, is also impor-tant. The Betz Law defined the maximum usable wind power at 60%. Different kinds of wind turbine have been invented, but the most efficient and durable is the 3 blades

How Turning Wind into ValueHow Turning Wind into ValueHow Turning Wind into ValueHow Turning Wind into Value

Summary :

• The energy problem

• Sustainability

• Wind Energy

• The Middelgrunden

project conditions

• Technical Specifica-

tions

• Production

• Economical calcu-

lates

“Without major changes in how we produce and use energy, we face significant risks to

our common energy security and the future of the environment” Nobuo Tanaka, director

of the International Energy Agency (IEA) Ministerial Meeting on Clean Energy,

Washington, July 19, 2010.

Friday 1 April

The IEA has estimated that without transition of fossil fuels to clean energy, emissions of

carbon dioxide, considered responsible for global warming, will double by 2050.

SustainabilitySustainabilitySustainabilitySustainability

In establishing the Brundtland CommissionBrundtland CommissionBrundtland CommissionBrundtland Commission, in 1983 the United Nations General Assembly

recognized that environmental problems were global in nature and determined that it was in

the common interest of all nations to establish policies for sustainable development. In this

commission sustainable development has been defined as the “development that meets

the needs of the present without compromising the ability of future generations to meet

their own needs.” Major shift energy is crucial for the sustainability of our planet. This shift

included the use of Renewable Energy in our production including wind.

horizontal axis wind turbine. Increase the blade number from 2 to 3 only gains 3% in aerodynamic efficiency but it reduces mostly the vibrations and instabilities. HAWT use the lift force to converting wind power in mechanical energy.

Sun Shine on Solar Energy Future Sun Shine on Solar Energy Future Sun Shine on Solar Energy Future Sun Shine on Solar Energy Future

Friday 4 March


Friday 1 April

Summary :


• Sustainability

• Wind Energy

• The Middelgrunden project conditions

• Technical Specifica-tions

• Production

• Economical calcu-lates

The Middelgrunden project The Middelgrunden project The Middelgrunden project The Middelgrunden project conditions conditions conditions conditions Off the Copenhagen coast, a wind farm stands in front of a thermal power plant. The Middelgrunden farm is an illustration of the turn taken by Denmark in their energy production in the early 1970s. Nearly 40 years later, with 3.752 GW of wind ca-pacity installed, wind tur-bines have provided 7.81 TWh in 2010, so 21.9% of the electricity consumed in this 5.5 million inhabitants country. Today, one of the symbols of Denmark is these huge wind turbines that mark the land-scape and coastline of the country. Currently, 78% of

the wind electricity comes from wind farms located on land, and 22% of offshore farms. By 2020, Denmark’s goal is to reach 50% of the electricity pro-duced by wind tur-bines, with half of which will comes from offshore farms. The installed capacity will be included between 6 and 6.2 GW.

The offshore wind farm of

Middelgrunden is located at

2km on the east of Copenha-

gen. This park consists of 20

BONUS 2MW wind turbines

disposed to form an arch.

With 40 MW of total installed

power, the park has a mean

production of some 90 TWh

of electricity annually,

equivalent to the consump-

tion of 20 000 households,

or 3% of the total electricity

consumption of Copenhagen.

When it was built in 2000,

the Middelgrunden offshore

wind farm was the world’s

largest one.

The wind power farm is located at less than 2km from

the shore in relatively shallow water with deep water

include between 3 and 5 meters. The 20 wind turbines

are disposed in a slight curve with 180 meters distance

between each and a total length of 3.4 km.

Wind measurementsWind measurementsWind measurementsWind measurements Meteorological measurements had been done on a 45 meter mast on the Middelgrunden site during 3 years between 1997 and 1999. Different data were registered, including the turbu-

lence intensity, the stability of the wind, the direction of the wind and its variation. In 45 metres height the average wind speed is 7.2 m/s, that can provide an energy intensity of 380W/m². And the annual park efficiency is estimated at 93%.

Wind Parameters at MiddelgrundenWind Parameters at MiddelgrundenWind Parameters at MiddelgrundenWind Parameters at Middelgrunden Wind speed at 50-m height............................ 7.2 m/s Weibull scale parameter at 50-m height.. 8.1 m/s Weibull shape parameter at 50-m height......... 2.3 Energy density at 50-m height............... 380 W/m²

The environmental considerationsThe environmental considerationsThe environmental considerationsThe environmental considerations Different aspects of the environmental impact has been analyzed during the project elaboration, including the risk of leaking debris and heavy metal contamination from the former dumpsite, the noise pollution, the influence on the free flow of water in the Øren-sund sea, the risk of collisions with vessels and the impact on flora and fauna.

The foundations

During the evaluation of the bids for the foundations, three possibilities have been considered, the monopi-le, the steel caisson type and the concrete slab. It has been conclude that the monopile was not realizable for this site because of the special type of limestone persent. The shal-low water and the protected sea

favored a gravity type of foundation. In shallow water the steel caisson can not compete with concrete. At large wind farm located in less than 10 meters depth water concrete is the most appropriated solution.

Technical SpecificationsTechnical SpecificationsTechnical SpecificationsTechnical Specifications The wind turbines used are delivered by Bonus Energy A/S, the oldest wind turbine factory in the world, which has delivered more than 3 500 turbines since 1980.

The model installed in Mid-

delgrunden farm is the big-

gest built by Bonus with a

generator effect of 2 WM a

rotor diameter of 76 m and a

blade tip height above sea

level of 102 m. Those tur-

bines based on onshore

models has been adapted

for an over sea application

in giving special considera-

tions to the fatigue

strength due to the combi-

nation of wave and wind

stress, the turbulence

caused by the short dis-

tance between each tur-

bines, the ice load com-

bined with the wind load.

The live length of the con-

struction has been esti-

mated at 50 years even

the life span of the tur-

bines is usually 20 years.


Friday 1 April

Summary :


• Sustainability

• Wind Energy



• Production


Grid connectionGrid connectionGrid connectionGrid connection The wind farm is connected from the central turbine to

the shore with 2 cables of 20 MVA transport capability, distanced of 15 m one from

the other. The distance be-tween this central turbine and the 30/132/400 kV transformer located at the Amager power plant on the shore, is 3.5 km. Others 20 MVA cables are used to connect the turbines to-gether in series. In each turbine a 30 kV dry trans-former is installed on the bottom of the tower.


Friday 1 April

Summary :


• Sustainability

• Wind Energy



• Production


ProductionProductionProductionProduction From march to December 2001, the first year of opera-tion, the turbines of the Middelgrunden farm produced 68 000 MWh, a very satisfactory ratio if we consider that 2001 was the poorest wind year of the last 22 years with only 80% of the normal wind per year. In 2002 the farm produced 100 GWh with 97% of the normal wind. More-over there were some maintenance operation has been done on the turbines during those two first years. The turbines have shown 5.7% better performance than guar-anteed by the constructor.

Economical calculates for the projectEconomical calculates for the projectEconomical calculates for the projectEconomical calculates for the project

The investment for this project has been estimated at 47.6 million €, for 40 MW in-

stalled. Annual production of the Middelgrunden wind farm is about 100 GWh of electric-

ity. Consequently, we can calculate that the investment is 1.2 €/kW and that the produc-

tion price of electricity is 0.044 €/kWh in taking a life time of 25 years and a service cost

of 1c€/kWh, which is the normal cost.

COCOCOCO2 savingssavingssavingssavings CO2 emission of a coal power plant P output = 40 MW, Efficiency=P output / P input = 0.36 _ P input = 40 / 0.36 = 111 MW W = 1 J/s P input = 111*3600*24*365/1000 = 3 504 000 GJ/year GCV coal (dry) = 28.54 GJ/t Mass Coal (dry) = 122 775 t/year %Ash in Coal = 15.8%, %C in ash of Coal = 85.1% Mass C=0.851*0.842*MassCoal = 87 973 t/year

Every kg of C produces 3.67 kg of CO2

Mass CO2 coal = 87 973 * 3.67 = 322 863 t/year

The wind power plant permit to save about 323 000 t/year of CO2

Considering 25 years lifetime it will permit to save more than 8 million tones of C02


Friday 1 April

Summary :


• Sustainability

• Wind Energy



• Production


BibliographyBibliographyBibliographyBibliography

University of Delft, Offshore Wind Energy – Ready to Power a Sustainable Europe, décem-

bre 2001.

Internet website of the Middelgrundens Vindmøllelaug cooperative:

www.middelgrunden.dk

Sørensen, H.C. et al., Prestudy for the Danish Offshore 750 MW Wind Program, Internatio-

nal Society of Offshore and Polar Engineers, ISOPE 2000 Conference Seattle 2000

Sørensen, H.C., Hansen, J., Experience from the Establishment of Middelgrunden 40 MW

Offshore Wind Farm, SPOK ApS & SEAS Wind Energy Centre

RETScreen International, Project Wind Power Plant, Offshore wind farm/ Copenhagen,

Denmark

Vølund and Jens Hansen, Department of Wind Energy, SEAS DENMARK, Middelgrunden

40 MW offshore wind farm near Copenhagen, Denmark, installed year 2000

Copenhagen Environment and Energy Office CEEO, ISEN 87-986690-3-6, the Middelgrun-

den Offshore Wind Farm

Jens H. Larsen Copenhagen, April 1999 (updated July 2000), Organization of wind power

in Copenhagen

Jens H. M. Larsen 1, Hans Christian Soerensen 2, Erik Christiansen, Stefan Naef, Per Vølund, KMEK - Copenhagen Environment and Energy Office (CEEO), Copenhagen Off-shore Wind 26-28 October 2005, Experiences from Middelgrunden 40 MW Offshore Wind

Farm

ISOPE 2000 Conference Seattle 2000, International Society of Offshore and Polar Engi-neers, Middelgrunden 40 MW offshore wind farm, a prestudy for the danish offshore 750

mw wind program

Non-technical Summary of the EIA, 1st Revision. January 2001, Environmental Impact

Assessment of the wind farm at the Middelgrunden Shoal.

Documents

How Turning Wind into ValueHow Turning Wind into Valuesebastiendufour.fr.free.fr/docs/wind.pdfsources are limited and may not meet the growing needs of the population. However, they