코리아헤럴드

The following is the 62nd in a series of articles focusing on the Korean government`s "green growth" strategy. The series will also introduce the increasing efforts of major advanced countries to promote a green economy. - Ed.

By Cho Chung-unTo replace fossil-fuel based energy with green energy, Korea plans to take full advantage of one of its most plentiful marine resources - tides.

Tidal power generation - which produces electricity as advancing and retreating ocean currents spin turbines - is the most effective alternative energy source for the country and will lead green energy production in the future, some experts believe.

"Every country has different environmental, geographical benefits. The western coastal area of the Korean Peninsula, where the difference between the ebb and flow of tides is great, is said to be a favorable location to develop tidal power plants," said Park Jin-soon, senior research scientist of the coastal engineering and ocean energy research department of the Korea Ocean Research and Development Institute.

"Unlike other energy sources, tidal power is predictable and (consistent)," he said.

According to a KORDI study, the potential oceanic energy in Korea is over 14,000 megawatts.

The electricity produced by tidal power plants would also be more cost effective than other types of renewable energy.

The estimated price per kilowatt of a tidal power plant is about 62 won to 90 won, a highly competitive price compared to other alternative energy sources such as solar power (600 won per kilowatt) and wind power (107 won per kilowatt).

Seoul is currently pushing ahead with building four tidal power plants, all on the western coast. Among them, three are in Gyeonggi Province - Sihwa, Incheon and Ganghwa - while one is in South Chungcheong Province - Garolim. The government began to promote these projects in the early 2000s as part of its effort to reduce carbon emissions and dependence on imported oil.

Korea, the world`s 10th-largest emitter of global warming gases, relies on oil imports for 44 percent of its energy needs.

By developing renewable energy, the government plans to reduce the dependence on oil to 35 percent by 2030. It plans to increase the share of renewable energy in the total energy mix to 5 percent in 2011, from the current 2.3 percent.

The government has been injecting billions of won into alternative energy development. It has also encouraged local manufacturers to invest in green energy by offering tax benefits. Hundreds of solar power plants, wind farms and small- and medium-sized hydro-electric plants are already operating or are under construction.

The government has been offering subsidies for manufacturing companies to develop new technology while encouraging utility companies to voluntarily invest in renewable technology under a renewable portfolio agreement. In the future, utility firms will be forced to have a certain share of their power supply come from green energy.

The Incheon Bay Tidal Power Plant, pushed by the Ministry of Land, Transport and Maritime Affairs, is the largest among the country`s envisioned tidal power plants.

The ministry plans to build the plant on an embankment bridging Yeongjong Island, where Incheon International Airport is located, with Ganghwa Island, an island in the estuary of the Han River, which is close to Gaeseong, a North Korean city where the two Koreas jointly operate an industrial complex.

One justification for the project is that the embankment can replace a bridge connecting the two islands. The Seoul government has a plan to construct a bridge linking Yeongjong Island with Gaeseong via Ganghwa Island to export goods produced in the North Korean industrial complex through Incheon International Airport.

The embankment will create a huge lake covering 157.45 square kilometers of sea. The government plans to build it by 2017 at a cost of 3.92 trillion won. When completed, it will have a capacity of 1,320 megawatts, five times more than the Rance Tidal Power Plant in France, currently the world`s largest tidal power plant with a capacity of 240 megawatts.

Located in northwestern France, the plant was built 40 years ago. There has been no major tidal power plant project undertaken since then.

The plant`s projected capacity of 1,320 megawatts is much larger than that of an average nuclear power plant, which is approximately 1,000 megawatts. According to a report by the government, the Incheon Bay TPP would meet 4.5 percent of national household demand for electricity and supply power to 60 percent of homes in Incheon City. Incheon is the country`s third largest city.

The first Korean tidal power plant that will go into operation is the Sihwa Tidal Power Plant. It is scheduled for completion next year. Located on Sihwa Lake in Gyeonggi Province, south of Yeongjong Island, the plant will have a capacity of 254 megawatts, slightly larger than the Rance Tidal Plant in France. Its production cost is approximately $250 million.

The method of energy generation at the Sihwa plant is simple. Tidal power plants generate electricity by using tidal currents to spin turbines. Dams are built in places where the difference between the tide`s ebb and flow is high.

So when the tide is on the rise, the water level on the lagoon side of the embankment becomes lower than the water level on the sea side. The Sihwa plant has 10 turbines that will start spinning and drive generators after the opening of underwater gates installed in the seawall. When the sea level drops, the plant`s eight sluice gates will open to empty out the water in the lagoon.

Sihwa`s turbines are manufactured by VA Tech Hydro, based in Austria. The Austrian company has agreed to transfer its turbine technology to Korea.

When completed, the Sihwa plant would help the country reduce carbon emissions by 315,000 tons, according to engineers. The plant was registered as a clean development mechanism project with the United Nations in 2006.

Experts said that the Sihwa TPP is set to open a new chapter in domestic alternative energy development.

"Development of pollution-free, ocean-source energy from tidal power plants will help make Korea less reliant on imported energy and reduce the volume of carbon emissions," said Kim Man-ki, director of the tidal power plant construction department of Korea Water Resources Corporation. The state-run company owns the Sihwa project.

"It satisfies the Korean government`s three policy goals - expanding alternative energy sources, acquiring certified emission reductions, and complying with the U.N. Framework Convention on Climate Change," Kim said.

There are more benefits. K-Water plans to make the plant and the surrounding area a draw for tourists.

"We are planning to turn Sihwa Lake into a clean energy park that also accommodates wind and solar power plants and a sprawling artificial wetland. The government expects 1 million visitors a year," Kim said.

Besides the Sihwa and Incheon Bay tidal power plants, the government has been studying the feasibility of tidal power plants in Garolim, south of the Sihwa TPP. At the same time, the Incheon City government in a joint venture with Daewoo Engineering and Construction has been separately pushing for the Ganghwa tidal power plant project in an area just to the north of the Incheon Bay TPP.

Tidal current power

Korean engineers have also been developing turbines and plants that generate electricity through the movement of tidal currents. The difference between a tidal power plant and a tidal current power plant is that the latter has no dams and can be operated 24 hours a day.

One of the advantages of having tidal current power plants is they have less of an impact on marine ecosystems.

"Tidal current power plants can be called underwater windmills. They have less of an environmental impact than tidal power plants because they do not need dams and embankments," Park of KORDI said.

Recently, a group of Korean engineers succeeded in generating 1,000 kilowatts of electricity by using an underwater turbine that generates electricity from tidal currents near Jindo, an island on the southwestern tip of the peninsula.

The electricity is enough for about 1,000 homes and the engineers plan to increase the power output to 1,200 kilowatts in the near future. The project, being undertaken by a consortium, is the first of its kind in Asia. The consortium, consisting of the Ministry of Land, Transport and Maritime Affairs, KORDI and Korea East-West Power Corp., a unit of Korea Electric Power Corp., aims to build more underwater power turbines capable of generating 50 megawatts by 2013.

Jindo is a meeting point of two-way tides coming from the South Sea and the West Sea. Korea East-West Power Corp. also plans to build tidal power generators in two other locations, which would allow the company to produce an additional 400 megawatts per day. This amount of green energy could effectively replace 180 billion won of crude oil consumption per year and reduce 700,000 tons of carbon emissions, company officials said.

"The speed of tidal streams in the sea off Jindo is among the fastest in the world. This is enough to generate green, economical power for the future," said an official of Korea East-West Power Co.

Tidal turbines harness the energy of these fast-moving streams with the added advantage that the resource is, unlike wind, predictable and consistent.

"This project is an Asia first and will help the country reduce its dependency on fossil fuels and secure reliable energy supplies for the future," he said.

The cost of installing one set of marine turbines is 15 billion won.

Another utility company, Korea Midland Power has also been developing a tidal current power plant in Wando, in the south of the Korean Peninsula.

Companies feeling the pinch

The country`s power companies are moving fast to secure sea-based renewable energy supplies.

But local power companies, due to lack of technological know-how, have been feeling the pinch from the government`s plan.

According to an official at a utilities company, producing renewable energy is not easy because it is not predictable, sustainable and costs a lot more than energy produced in traditional ways.

"We feel a burden to meet the mandatory standard to be adopted in 2012, because producing renewable energy is not as easy as it seems," he said. "Power companies may have to raise the price of electricity for end users."

Last month, the country`s nine state-run energy companies reached a renewable portfolio agreement to voluntarily pledge a combined 3 trillion won investment in building and developing renewable energy production facilities across the country by 2011.

According to the agreement, the utility companies will dedicate more resources to renewable energy, including solar, tidal and wind power. They promised to expand research and development efforts in the sector.

The announcement came as the government plans to adopt the Renewable Portfolio Standards regulation, which obligates utility companies to produce 3 percent of their electricity from renewable sources in the next three years.

Renewables must make up 10 percent of supply by 2020.

The mandatory system - already adopted in some advanced countries - imposes penalties if power companies fail to meet the standard.

Between 2006 and 2008, the companies spent a combined 605.9 billion won to increase generation of electricity through renewable means.

Environmental impact

Controversy is growing over the tidal plants planned in Korea because of their impact on the environment. Environmental groups are calling for a cautious approach, saying the marine power plants would damage sea life and marine ecosystems.

Referring to the large-scale land reclamation works that have to be undertaken before building tidal power plants, environmental activists say the plants would destroy entire ecosystems.

Park of KORDI, however, said environmental changes are inevitable when installing plants for alternative energies.

"Environmental issues have been raised regarding tidal power plants. But other renewable power plants using solar and wind also cause negative impacts on the surrounding environment. It is unavoidable," he said. (christory@heraldm.com)