Offshore wind farm promises cleaner energy
Published on : Monday 30-11--0001
Increasing amount of pollution and depleting fossil fuels are driving the energy sector to look for other alternative energy sources. Renewable energy, mainly sourced from sunlight and the wind, are becoming better alternatives to fossil fuels.
By 2020, renewable energy is expected to account for almost 26 percent of global electricity generation, according to Medium-term Renewable Energy report1.
When compared to other countries, India has the fifth largest onshore wind market with almost 27 GW of total installed capacity. However, India has a huge demand for large scale and indigenous clean energy production to fulfill the needs of its rapidly growing economy. Offshore wind energy could play a vital role in generating large scale wind energy from locations where there is high energy demand.
In India, the International Renewable Energy group, DNV GL, is working in collaboration with the Ministry of New and Renewable Energy to prepare a roadmap for setting up offshore wind farms in Gujarat and Tamil Nadu. At the initial stage, a 100-megawatt offshore wind energy project will be installed in the coastal areas of Gujarat within the next three years. At this pace, it would take another three to five years to see commercial offshore wind energy projects in India.
Offshore wind energy
Based on the location of the wind turbines, the wind energy procurement can be broadly classified into two categories – Online wind energy and offshore wind energy. Offshore wind energy has 40 percent higher energy output than onshore wind energy, which shows why government and industries are giving more emphasis to this sector.
However, offshore turbines have to operate in a harsh marine environment, very vulnerable to erosion. Even the high wind speed, which is considered as the main advantage of offline wind energy, can be a negative factor, as wind turbines tend to stop working when wind speed is over 25 meters per second.
To overcome the challenges, the size of the turbine parts has been increased, improving durability and increasing output. For installing more turbines, a sophisticated logistical setup including construction, transportation, and installation is required, so for setting up wind turbines offshore, logistical issues are the biggest challenge. In most of the cases, the location of the power plants can be miles away from the shore, and it would be difficult to access during bad weather conditions. So, even a minor service-related issue can exponentially increase the cost. Hence, a highly tested and proven technology is important for gaining investor confidence and higher returns.
Challenges and opportunities
Many industry players are establishing their presence in the offshore wind energy sector. Siemens, Vestas, GE Energy, Senvion, Sinovel, Alstom, Areva, Clipper Windpower, and Doosan Heavy Industries & Construction, and Gamesa Technology are some of the leading players in the market. Though there are challenges regarding cost and logistical inconveniences, offshore wind energy is expected to be more efficient aided by fast evolving technology and cost competitiveness due to government subsidies.
In countries like the US, almost half of the total population lives in coastal areas. Due to this, the cost and demand for energy are high, and the availability of land-based renewable energy resources is also limited in coastal areas. In this scenario, offshore wind resources are the best alternative and have the potential to supply required quantities of renewable energy to major coastal cities like New York, Los Angeles, and Boston.
Commercial-scale offshore wind energy
Commercial offshore wind energy generation is similar to onshore wind facilities. The key difference is that the wind turbine generators used for offshore wind energy generation are modified to prevent corrosion. Moreover, the foundations of the offshore wind turbines are specially designed to endure the tough environmental situations such as powerful waves, strong winds and also ice flows.
Industries and Technology experts are trying different ways to set up offshore wind turbines. Innovative foundation and floating wind turbines are some of the ways they use to stabilize wind power generation even in the challenging conditions of deep waters. To gain maximum benefit from the strong and steady winds, offshore turbines are designed bigger than onshore turbines. They have higher energy generation capacity. On an average, the tower height of offshore turbine is more than 200 feet with the rotor diameter of 250 to 430 feet. The height of the offshore wind turbine can easily reach 500 feet.
Storage and shifting
The energy generated from offshore wind turbines has to be transferred to shore and connected to the power grid. A power cable connects each turbine to an Electric Service Platform (ESP). The ESP is placed within the turbine premises, and it functions as a substation and also a common electrical collection point for all the wind turbines. In addition to this, ESPs can also function as the main service facility which can also be used as a communication station, helipad, staff accommodation and storage for emergency backup equipment.
When the power from the offshore wind turbines are collected, high voltage cables connected to the ESP transfer the power to the substation located on shore and the integration of power in the grid happens. To avoid damages caused by fishing nets or anchors and to minimize the corrosion caused by the harsh marine environment, the cables connected to ESP are buried under the seabed. These cables are very expensive and require a major proportion of the investment. The requirement of cable relies on multiple factors – distance from the shore to the location of the offshore wind turbine, space between each turbine and the presence of hindrances that require rerouting the cable in certain directions.
IRENA’s Innovation Outlook: Offshore Wind report predicts that the offshore wind energy sector is capable of out powering today’s commercial technology and playing an important role in fulfilling global energy demand in the next three decades2.
Development in technology has reduced costs and expanded the market for wind energy. With onshore wind energy facing cost competitiveness with traditional power generation technologies, more focus is required on offshore wind energy generation, as it makes use of high wind resource areas.
By 2030, the global offshore wind energy market is expected to reach 100GW of total installed capacity. Though government subsidies and incentives could be the key driver of this transformation, reducing wind energy production costs has a much more important role. Once the cost and logistical challenges are addressed by new technological developments, offshore wind energy will be able to cover the major proportion of the world’s electricity needs.
Quote:
"The position of ‘global manufacturing hub for the wind industry’ is today “vacant.” China has not been able to break into the global market, but India is well positioned to do so. India will soon be the global manufacturing hub for wind turbines, just as China is for solar panels today,"
- Tulsi Tanti, Chairman, and Managing Director, Suzlon Energy3
"We are preparing India for offshore wind (and) providing the Ministry of New and Renewable Energy a road map for offshore wind for Gujarat and Tamil Nadu. It would take three to five years that we see commercial offshore winds projects in India,"
- Mathias Steck, Executive Vice President, and Regional Manager, DNV GL, an international renewable energy group4
“We are witnessing a transformation of global power markets led by renewables and, as is the case with other fields, the center of gravity for renewable growth is moving to emerging markets,”
- Dr. Fatih Birol, Executive Director, International Energy Agency5