The southwestern sea of Korea contains an archipelago with several straits through which strong tidal currents flow, which are advantageous for the development of tidal current energy.
The Uldolmok Strait experiences peak tidal current speeds of up to 6 m/s with the width of the strait being approximately 300 m, and a water depth of 20 to 32 m below datum level. The tidal range is up to 4/5 in spring tides and around in the neap tides. According to earlier studies the annual energy density of the Uldolmok Strait is 52.1MWh/m2.
The Uldolmok Tidal Current Power Pilot Plant currently produces tidal current energy using a cross-flow Helical Turbine (1 m diameter x 2.5 m length). Long helical blades run along a cylindrical surface like a screw thread, which create a reaction thrust that rotates the turbine faster than the flow of water itself. Due to its axial symmetry, the turbine always develops unidirectional rotation, even in reversible tidal currents. This provide the advantage of simplified design and exploitation of the double-action tidal power plants
The site includes a jacket-type support structure measuring 50 m tall x 36 m long x 16 m wide with a total weight of 1360 tons. The plant additionally functions as a sea test facility for tidal current energy.
The Uldolmok Strait in the Yellow Sea, at Jindo Island, South Jeolla, South Korea.
The Low Carbon Green Growth Basic Act (Feb 2009) and the Green Growth 5-Year Plan: Restructuring S&T R&D Policies (July 2009) were passed in the hope that “A national paradigm that aims to deal with the challenges of climate change while at the same time create jobs and restore growth by minimizing environmental degradation and carbon emissions.” By 2020, South Korea hopes to produce 5,377 GWh/yr from ocean renewable energy. This could reach 113,000 residents and reduce carbon dioxide emissions by 2.3 million tons.
Korea East West Power Co. and South Jeolla Province signed an investment agreement in 2006 to develop a tidal plant in Jindo. Hyundai Construction & Engineering was chosen to construct a test power plant, while Hyundai Heavy Industries was named to develop generators and Iljin Electric was chosen to manufacture mechanical equipment.
The plant was commissioned in May 14, 2009 by the South Korean government. The plant cost 10 million USD and has an installed capacity of 1,000 KW (1 MW), generating 2.4 GWh annually, sufficient to meet the demand of 430 households.
In June 2011 Hyundai Heavy Industries completed the site trial of a prototype 500 kW tidal current power system at the site.
The prototype tidal current power system directly connects a tidal turbine, a gearbox and a generator for power transmission.
The system can operate regardless of current direction using a specially designed turbine system, the company said. After completing factory and basin tests last year, the company produced target power generation from site trials and the system continues to operate at the site.
The Korean Institute of Ocean Science and Technology (KIOST) is developing a 200kW active-controlled tidal current energy converter (TEC), which aims to develop, validate and suggest a standard model for an efficient and wide scope applicable TEC that actively manages variations in tidal current speeds and directions while controlling flow amounts. The cassion-type gravity-based support structure associated with the TEC is 15 m diameter x 9.5 m height, and a total weight of 350 tons.
The 200kW active-controlled TEC is planned to be installed in the Uldolmok test site for open sea testing in 2019.
A project for an open sea test bed with five berths of a collective 4.5MW capacity, known as the Korea Tidal Current Energy Center (K-TEC), is planned to be built on two possible sites around the Uldolmok Strait (single 0.5MW berth) and the Jang-Juk Strait (four 1 MW berths).
It is planned to expand the facility to 50 MW by 2018.
Key Environmental Issues
No studies have been conducted to analyse the direct environmental effects of the pilot turbines, much less the effects once the project expands to the planned 50 MW stage two of development. However, the project will reduce reliance on greenhouse gases for energy in accordance with UNFCCC.