Jeff Postelwait, Associate Editor, Electric Light & Power
May 29, 2013
This level of cost competitiveness is thanks to supportive public policy that has, so far, not been extended to include offshore wind energy, according to the draft.
About 5 GW of offshore wind generation capacity is installed worldwide, with an equal amount in development or under construction. Top countries in the offshore wind market include the U.K., Belgium, The Netherlands, Norway, Finland, Denmark, Sweden and Germany. The E.U. set a goal of 40 GW in offshore wind capacity by 2020 and 150 GW by 2030.
In India, the top areas in offshore wind potential are the coastlines of Karnataka, Kerala and Goa. Wind resource data gathered from the coastlines of Rameshwaram and Kanyakumari in Tamil Nadu and Gujarat also show a potential of about 1 GW.
Obstacles to offshore wind deployment include resource identification, power grid interconnection and operation, and the development of adequate transmission infrastructure, according to the draft.
The role of the Ministry of New and Renewable Energy in the deployment of offshore wind will include monitoring offshore wind development in the country, coordination with other ministries and departments, issuing guidelines and directives for development of offshore wind energy, overseeing the working of National Offshore Wind Energy Authority and extending necessary support and promoting indigenous research for technology development.
Better late than never. I had been advocating offshore wind farms in India since a decade.
Offshore Wind Farms
Offshore wind power:
Offshore wind power refers to the construction of wind farms in bodies of water to generate electricity from wind. Better wind speeds are available offshore compared to on land, so offshore wind power’s contribution in terms of electricity supplied is higher.
Power P = 0.5 p A V3 .. .. (1)
Where P = Power, p density of air,V=speed of the wind and A is the area of the intercepted airstream (equal to the ‘swept’ by the rotor).
In standard conditions (sea level, temperature 15 degrees Celsius) the density of the air is 1.225 kg/m3. So the amount of Power intercepted by each square rotor is:
P=0.612 V3 Watts … (2)
For Example, if the wind speed is 6 m/s (a moderate breeze) the power intercepted per square meter is 0.612 X 63 = 132 W; but if the speed rises to 24 m/s (a severe gale) the power becomes 0.612 X 243 = 8460 W. This massive increase is due to cubic relationship between wind speed and power by equation (2). Here the word’ intercepted’ rather than ‘captured’ is used because the above figures relate to the power in the wind, not the amount actually extracted by a turbine rotor. Large modern turbines typically capture up of about 50% of the wind power presented to them.
Betz's law is a theory about the maximum possible energy to be derived from a wind turbine developed in 1919 by the German physicist Albert Betz. According to Betz's law, no turbine can capture more than 59.3 percent of the kinetic energy in wind. The ideal or maximum theoretical efficiency n max (also called power coefficient) of a wind turbine is the ratio of maximum power obtained from the wind to the total power available in the wind. The factor 0.593 is known as Betz's coefficient. It is the maximum fraction of the power in a wind stream that can be extracted.
Economics and benefits
Offshore wind power can help to reduce energy imports, reduce air pollution and greenhouse gases (by displacing fossil-fuel power generation), meet renewable electricity standards, and create jobs and local business opportunities.
COST COMPARISON OF ONSHORE AND OFFSHORE WIND FARMS
Onshore
Investment of about $1.5 million per MW
Levelized cost of 6-7 cents per kWh
O&M – 1-3% of capital costs
May be built in smaller units
Offshore
Investment of $2.3 million per MW
Levelized cost of about 10-11 cents per kWh
Higher O&M – 40$ per kW and 0.7 cents per kWh variable
Large turbines and farms required
In spite of the higher costs and the uncertainties involved in offshore wind, research in this sector has been significant, and the main reason is the potential offered by offshore wind turbines, especially in lands close to water
At the end of 2011, there were 53 European offshore wind farms in waters off Belgium, Denmark, Finland, Germany, Ireland, the Netherlands, Norway, Sweden and the United Kingdom, with an operating capacity of 3,813 MW,[ while 5,603 MW is under construction
USA, China, South Korea, Taiwan, France and Japan have ambitious plans to go in for offshore wind farms on a massive scale.
Length of coastline of India including the coastlines of Andaman and Nicobar Islands in the Bay of Bengal and Lakshwadweep Islands in the Arabian Sea is 7517 km. Length of Coastline of Indian mainland is 6100 km.
Thorough Wind studies have to be carried out along the coast to identify the prospective offshore wind farm sites. Based on these studies a Pilot project can be started by MNRE which will help as a Demonstration project.
Accurate wind measurements at the site are the constraint. Many a time wind data is extrapolated to the hub height at sites where the wind turbines are to be erected. In the US in California wind farm developers used to monitor (Anemometers, Anemographs) in the past at the sites where wind turbines to be erected (Now Wind Masts). This gives more or less reliable wind data and hence the turbine output.Unfortunately in some cases Wind Farm developers can't wait for years to measure the wind data(In some cases to avail the tax benefits quickly) and hence correlate the nearest wind mast data. That is why there will be variation in the output. Moreover terrain also plays an important role in wind energy production.
Remote sensing measurement techniques enable measurements to hub height and beyond. There are resource measurement technique using sodar and lidar which need to be adopted in India along with at least 75 meter Wind masts.
As of September 2012, the Greater Gabbard Wind Farm in the United Kingdom is the largest offshore wind farm in the world at 504 MW, followed by Walney Wind Farm (367 MW), also in the UK. The London Array (630 MW) is the largest project under construction. The biggest producer of wind energy is Horns Rev 2 in Denmark even though it has a smaller nameplate capacity than a few other wind farms. In 2011 Horns Rev 2 produced 911.03GigaWatt-hours (GWh). The second largest producer is Rodsand 2 with 833,47 GWh produced in 2011. In terms of total production since introduction Horns Rev 1 remains the largest with 5.200,57 GWh produced since the park opened. Nysted 1, also in Denmark, is the second largest wind farm in the world in terms of total energy produced. Nysted 1 has produced 4.521,45 GWh since its start. Third is Horns Rev 2 with 2.002,66 GWh produced.
Despite economic and political uncertainties, weakening investments, grid connection issues and a dip in the U.S. onshore wind energy market, offshore wind around the world continues its momentum. The European Wind Energy Assn. (EWEA, Brussels, Belgium) says 132 offshore wind turbines in 13 wind farms (523.2 MW of capacity) came online in the first six months of 2012 — an increase of 50 percent from the same period in 2011. EWEA also reports that as of June 2012, 4.3 GW of offshore turbines had been installed off the European coast, and conservative estimates are that the total could grow to 25 GW by 2020. In Japan a huge new 1-GW offshore wind farm — the world’s largest to date — was announced in January to replace the nuclear power capacity lost in the March 2011 earthquake and tsunami. Although the U.K. (the world’s leader in installed offshore units), Germany, Belgium, France and Italy lead the offshore surge, China’s offshore wind industry is reportedly poised for huge growth. Moreover, Morocco and Tunisia have active developments, and in 2014, Egypt will begin work on a 200-MW wind farm in the Gulf of Suez. In fact, the offshore wind analysts at 4C Offshore (Suffolk, U.K.) are tracking 1,301 offshore wind projects in 38 countries with a total nameplate power capacity of 3.6 GW
Conclusions and Prognosis
With advanced wind turbine technology and more accurate wind data at higher heights available, there is wide scope to expand wind farms in India. Wind farm co-operatives can be started in India. A Wind Fund can be created and the investments in it by Individual Income Tax payers can be exempted under Section 80 C. This way there will be funds available for large scale wind farms besides large participation of people in the Wind Farms. Offshore wind farms will be future energy option to supplement conventional power. With extensive research on large size wind turbines and installation techniques of offshore wind turbines, the cost of power generation through offshore wind farms is expected to come down to be competitive with conventional power. USA, China, South Korea, Taiwan, France and Japan have ambitious plans to go in for offshore wind farms on a massive scale.It is hoped MNRE will initiate at least a Pilot project of Offshore Wind Farm in India. All modern techniques of wind assessment have to be undertaken which will identify prospective locations to set up offshore wind farms in the country. Wind masts to obtain wind data at higher hub heights (about 80 m) need to be carried out at as many locations as possible besides resource measurement using Sodar and LIDAR. The Centre for Wind Energy Technology(C-WET) under the Ministry of New and Renewable Energy (MNRE) launching a reassessment programme to validate the revised estimates for wind power potential made by various organisations will help generate data for taller towers being erected in the country in the near future. C-WET had estimated the potential of 102GW at hub height of 80 metres, and a decade back a potential of 49.2 GW was estimated at 50 metres hub height.
It is hoped at least a Pilot Offshore wind farm is started by MNRE so that the Private Industry will follow suit.
May 29, 2013
India's Ministry of New and Renewable Energy has released a draft national offshore wind energy policy for 2013. The draft policy was written with input from a steering committee on offshore wind energy. According to the draft, onshore wind energy has reached a stage of deployment that makes it competitive with traditional fossil fuel power generation.
This level of cost competitiveness is thanks to supportive public policy that has, so far, not been extended to include offshore wind energy, according to the draft.
About 5 GW of offshore wind generation capacity is installed worldwide, with an equal amount in development or under construction. Top countries in the offshore wind market include the U.K., Belgium, The Netherlands, Norway, Finland, Denmark, Sweden and Germany. The E.U. set a goal of 40 GW in offshore wind capacity by 2020 and 150 GW by 2030.
In India, the top areas in offshore wind potential are the coastlines of Karnataka, Kerala and Goa. Wind resource data gathered from the coastlines of Rameshwaram and Kanyakumari in Tamil Nadu and Gujarat also show a potential of about 1 GW.
Obstacles to offshore wind deployment include resource identification, power grid interconnection and operation, and the development of adequate transmission infrastructure, according to the draft.
The role of the Ministry of New and Renewable Energy in the deployment of offshore wind will include monitoring offshore wind development in the country, coordination with other ministries and departments, issuing guidelines and directives for development of offshore wind energy, overseeing the working of National Offshore Wind Energy Authority and extending necessary support and promoting indigenous research for technology development.
For Full Article:
Comment by Anumakonda Jagadeesh
Offshore Wind Farms
Offshore wind power:
Offshore wind power refers to the construction of wind farms in bodies of water to generate electricity from wind. Better wind speeds are available offshore compared to on land, so offshore wind power’s contribution in terms of electricity supplied is higher.
Power P = 0.5 p A V3 .. .. (1)
Where P = Power, p density of air,V=speed of the wind and A is the area of the intercepted airstream (equal to the ‘swept’ by the rotor).
In standard conditions (sea level, temperature 15 degrees Celsius) the density of the air is 1.225 kg/m3. So the amount of Power intercepted by each square rotor is:
P=0.612 V3 Watts … (2)
For Example, if the wind speed is 6 m/s (a moderate breeze) the power intercepted per square meter is 0.612 X 63 = 132 W; but if the speed rises to 24 m/s (a severe gale) the power becomes 0.612 X 243 = 8460 W. This massive increase is due to cubic relationship between wind speed and power by equation (2). Here the word’ intercepted’ rather than ‘captured’ is used because the above figures relate to the power in the wind, not the amount actually extracted by a turbine rotor. Large modern turbines typically capture up of about 50% of the wind power presented to them.
Betz's law is a theory about the maximum possible energy to be derived from a wind turbine developed in 1919 by the German physicist Albert Betz. According to Betz's law, no turbine can capture more than 59.3 percent of the kinetic energy in wind. The ideal or maximum theoretical efficiency n max (also called power coefficient) of a wind turbine is the ratio of maximum power obtained from the wind to the total power available in the wind. The factor 0.593 is known as Betz's coefficient. It is the maximum fraction of the power in a wind stream that can be extracted.
Economics and benefits
Offshore wind power can help to reduce energy imports, reduce air pollution and greenhouse gases (by displacing fossil-fuel power generation), meet renewable electricity standards, and create jobs and local business opportunities.
COST COMPARISON OF ONSHORE AND OFFSHORE WIND FARMS
Onshore
Investment of about $1.5 million per MW
Levelized cost of 6-7 cents per kWh
O&M – 1-3% of capital costs
May be built in smaller units
Offshore
Investment of $2.3 million per MW
Levelized cost of about 10-11 cents per kWh
Higher O&M – 40$ per kW and 0.7 cents per kWh variable
Large turbines and farms required
In spite of the higher costs and the uncertainties involved in offshore wind, research in this sector has been significant, and the main reason is the potential offered by offshore wind turbines, especially in lands close to water
At the end of 2011, there were 53 European offshore wind farms in waters off Belgium, Denmark, Finland, Germany, Ireland, the Netherlands, Norway, Sweden and the United Kingdom, with an operating capacity of 3,813 MW,[ while 5,603 MW is under construction
USA, China, South Korea, Taiwan, France and Japan have ambitious plans to go in for offshore wind farms on a massive scale.
Length of coastline of India including the coastlines of Andaman and Nicobar Islands in the Bay of Bengal and Lakshwadweep Islands in the Arabian Sea is 7517 km. Length of Coastline of Indian mainland is 6100 km.
Thorough Wind studies have to be carried out along the coast to identify the prospective offshore wind farm sites. Based on these studies a Pilot project can be started by MNRE which will help as a Demonstration project.
Accurate wind measurements at the site are the constraint. Many a time wind data is extrapolated to the hub height at sites where the wind turbines are to be erected. In the US in California wind farm developers used to monitor (Anemometers, Anemographs) in the past at the sites where wind turbines to be erected (Now Wind Masts). This gives more or less reliable wind data and hence the turbine output.Unfortunately in some cases Wind Farm developers can't wait for years to measure the wind data(In some cases to avail the tax benefits quickly) and hence correlate the nearest wind mast data. That is why there will be variation in the output. Moreover terrain also plays an important role in wind energy production.
Remote sensing measurement techniques enable measurements to hub height and beyond. There are resource measurement technique using sodar and lidar which need to be adopted in India along with at least 75 meter Wind masts.
As of September 2012, the Greater Gabbard Wind Farm in the United Kingdom is the largest offshore wind farm in the world at 504 MW, followed by Walney Wind Farm (367 MW), also in the UK. The London Array (630 MW) is the largest project under construction. The biggest producer of wind energy is Horns Rev 2 in Denmark even though it has a smaller nameplate capacity than a few other wind farms. In 2011 Horns Rev 2 produced 911.03GigaWatt-hours (GWh). The second largest producer is Rodsand 2 with 833,47 GWh produced in 2011. In terms of total production since introduction Horns Rev 1 remains the largest with 5.200,57 GWh produced since the park opened. Nysted 1, also in Denmark, is the second largest wind farm in the world in terms of total energy produced. Nysted 1 has produced 4.521,45 GWh since its start. Third is Horns Rev 2 with 2.002,66 GWh produced.
Despite economic and political uncertainties, weakening investments, grid connection issues and a dip in the U.S. onshore wind energy market, offshore wind around the world continues its momentum. The European Wind Energy Assn. (EWEA, Brussels, Belgium) says 132 offshore wind turbines in 13 wind farms (523.2 MW of capacity) came online in the first six months of 2012 — an increase of 50 percent from the same period in 2011. EWEA also reports that as of June 2012, 4.3 GW of offshore turbines had been installed off the European coast, and conservative estimates are that the total could grow to 25 GW by 2020. In Japan a huge new 1-GW offshore wind farm — the world’s largest to date — was announced in January to replace the nuclear power capacity lost in the March 2011 earthquake and tsunami. Although the U.K. (the world’s leader in installed offshore units), Germany, Belgium, France and Italy lead the offshore surge, China’s offshore wind industry is reportedly poised for huge growth. Moreover, Morocco and Tunisia have active developments, and in 2014, Egypt will begin work on a 200-MW wind farm in the Gulf of Suez. In fact, the offshore wind analysts at 4C Offshore (Suffolk, U.K.) are tracking 1,301 offshore wind projects in 38 countries with a total nameplate power capacity of 3.6 GW
Conclusions and Prognosis
With advanced wind turbine technology and more accurate wind data at higher heights available, there is wide scope to expand wind farms in India. Wind farm co-operatives can be started in India. A Wind Fund can be created and the investments in it by Individual Income Tax payers can be exempted under Section 80 C. This way there will be funds available for large scale wind farms besides large participation of people in the Wind Farms. Offshore wind farms will be future energy option to supplement conventional power. With extensive research on large size wind turbines and installation techniques of offshore wind turbines, the cost of power generation through offshore wind farms is expected to come down to be competitive with conventional power. USA, China, South Korea, Taiwan, France and Japan have ambitious plans to go in for offshore wind farms on a massive scale.It is hoped MNRE will initiate at least a Pilot project of Offshore Wind Farm in India. All modern techniques of wind assessment have to be undertaken which will identify prospective locations to set up offshore wind farms in the country. Wind masts to obtain wind data at higher hub heights (about 80 m) need to be carried out at as many locations as possible besides resource measurement using Sodar and LIDAR. The Centre for Wind Energy Technology(C-WET) under the Ministry of New and Renewable Energy (MNRE) launching a reassessment programme to validate the revised estimates for wind power potential made by various organisations will help generate data for taller towers being erected in the country in the near future. C-WET had estimated the potential of 102GW at hub height of 80 metres, and a decade back a potential of 49.2 GW was estimated at 50 metres hub height.
It is hoped at least a Pilot Offshore wind farm is started by MNRE so that the Private Industry will follow suit.
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