New construction method that can monitor changes in surroundings of offshore wind power apartment complex in order to overcome negative perception towards renewable energy and install basic structures for offshore wind power that can weigh between 500 to 600 tons using the difference in inner and outer pressures at a 30% cheaper cost has been developed for the first time by Korea Electric Power Corporation’s (KEPCO) Korea Electric Power Research Institute (KEPRI). It will be interesting to see whether this development will propel South Korea to become one of the powerhouses in the renewable energy industry.
◊KEPRI develops offshore wind power environmental monitoring system
KEPRI has completed its R&D process on offshore wind power environmental monitoring system that can observe and send any environmental change around offshore wind power apartment complexes in real-time and applied the system to the test site located in the southern part of Yellow Sea.
South Korea has regularized the development of eco-friendly energy through large-scale offshore wind power farms when it announced its plan to push for 2.5GW offshore wind farm in the southern part of Yellow Sea. This is a large-scale project that will require about $8.53 billion (10 trillion KRW) of investment. However, the project has not gained proper momentum due to realistic issues such as approval from local governments and opposition from residents and compensation for damage.
KEPRI has started its R&D process for the environment monitoring system since December of 2016 and it has made results that are higher than expectations in less than three years. Considering the fact that KEPCO cannot directly participate in the project, KEPRI has performed every responsibility of a public enterprise. Also, there are now high expectations that South Korean Government’s ‘Renewable Energy 3020’ policy will gain even more momentum due to the recent development of the environment monitoring system.
KEPRI’s monitoring system uses X-band radar, sound detector, buoy that observes meteorological changes, and unmanned vessel to observe environmental information such as wave, tidal current, weather conditions, and water quality within 4km of radius in real-time. Observations are sent to a situation room through an information management system developed by KEPRI in real-time and are provided immediately to users who need environmental information.
Although large-scale wind power farms are created in Jeju (30MW) and the southern part of Yellow Sea (60MW), there was not any system that can detect any environmental change in real-time before and after the farms are created. Basically, there was not a plan that can solve resident-related issues such as noise issue and destruction of marine ecosystem through a scientific basis.
Also, investigators have to be present at offshore wind power farms to observe environmental changes in order to perform maintenance and to obtain an approval for construction. Because offshore wind power equipment needs continuous maintenance as it is exposed to sea water and thus prone to corrosion, there have been many cases where maintenance has been difficult due to limited access.
This is a stark contrast to Denmark’s case where Denmark came up with a report based on results from seven years of monitoring in order to persuade residents. Also, Norway has developed Wave X system using radars and applied to analysis of marine environment while France is using 3D scanning, which is an observation method based on sound, to manage facilities within ports. Many advanced countries are actively introducing various observation methods such as radar and sound technology to observe marine environment.
KEPRI believes that its environmental monitoring system can secure safety of investigators and easily collect useful information as it can observe changes without having any person present. Also, it emphasizes the fact that offshore wind power structures can be managed more economically and smoothly as the system can monitor geographical change at the bottom of offshore wind power structures and collect data that can impact the lifespan of offshore wind power generators.
KEPRI is planning to monitor environment of the test site located in the southern part of Yellow Sea until 2020 and develop guidelines for marine activities near offshore wind power farms and offshore wind power simulator using the data it collects from observation. It is currently developing the guideline so that it can actually be used for construction and operation of farms and it is also planning to include information regarding vessel operation and fishery operation near offshore wind power farms to the guideline in order to resolve any complaint that residents may have. Also, simulator is being developed so that it can predict the amount of damage that natural disasters can have on farms and present solutions in advance.
“We are currently linking information from observing environmental changes near offshore wind power farms to a geographical information system.” said Kim Min-seok who is a senior researcher for Renewable Energy Laboratory. “Our research focuses on environment and people first and we are going to put in maximum efforts in order to have renewable energy be accepted by residents and to break any negative perception.
◊KEPRI develops a new offshore wind power generator installation practice
KEPRI completed its R&D process on ‘offshore wind power suction bucket method’ that can finish basic construction of wind power generators on the sea in just one day using differential pressure and applied the method to 3MW commercial turbines and verified technicality and safety at the same time.
South Korea has pile drove posts to the ocean floor in order to set up large-scale offshore wind power generators. If offshore wind power structures are considered as a ‘nail’, they are stabilized to the ocean floor by hammering. As a result, 3,000-ton crane is used in order to install offshore wind power structures that weigh between 500 and 600 tons.
KEPRI’s suction bucket method only uses differential pressure and does not cause any vibration or noise. KEPRI’s method is a new type of basic installation method that mounts large steel pipe piles on the ocean floor and passes water by operating suction pumps installed at the top and it is able to install wind turbines on the sea using just the difference in inner and outer pressures of piles. This method minimizes use of large equipment such as marine crane and reduces installation time to just one day. As a result, it can reduce days of construction by 29 days.
This method also has high economic feasibility. It can reduce manufacturing and installation cost by more than 30% compared to jacket foundation practice. $2.56 million (3 billion KRW) can be reduced per 5MW wind power turbine. If 50% of lower foundation of the test site located at the southern part of Yellow Sea is replaced with suction buckets, $154 million (180 billion KRW) of construction cost can be reduced. In addition, KEPRI is also developing a ‘batch installation system that assembles structures on land and transfers and installs the structures on the sea.
KEPRI’s research has been recognized and it was awarded ‘Outstanding Project Award’, which is the first in South Korea, by DFI (Deep Foundations Institute) and it was also awarded the most outstanding project in wind power field by Korea Energy Technology Evaluation and Planning demonstrating the superiority of its suction bucket practice.
“Our suction bucket offshore wind power system has been producing power smoothly ever since we started operating it in March of last year.” said Yoo Moo-sung of Renewable Energy Laboratory. “It has accumulated about 7GWh of power.”
Staff Reporter Choi, Jaepil | jpchoi@etnews.com