S. Korea keen on turning waste to renewable energy
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Xinhua, August 31, 2011
South Korea has achieved economic growth at an astonishing rate in the last 50 years, and the greater wealth brought by the country's rapid development has prompted people to consume more commodities and then throw them away.
Nearly 90 percent of the waste was sent to landfills two decades ago, forcing the country to embark on a search for new solutions to deal with waste.
Now, the country has turned its eyes to plenty of new technologies that transform waste into resources. Turning waste into energy has been at the forefront of the green movement that has taken off under the Lee Myung-bak administration that emphasizes "low carbon, green growth."
Energy production from waste has indeed emerged as the most efficient and cost-effective method to realize the goal of "low carbon, green growth."
Currently, more than 76 percent of new and renewable energy is generated from waste, and the manufacturing cost of renewable energy is only about 10 percent of that of solar energy and 66 percent of that of wind energy, according to the Ministry of Environment. Since 2007, the environment ministry has gradually increased government subsidies on expanding power generation facilities from waste.
One of those facilities is situated where used to be Seoul's landfill site for 15 years. Mapo Resource Recovery Plant is a state-of-the-art resource incineration facility that cost over 171 million U.S. dollars and opened in 2005.
Located between two parks in western Seoul and built on two former mountain landfill sites, the facility now deals with waste from five of Seoul's 25 districts, processing an average of 650 tons of waste each day.
To put it simply, waste is transported to Mapo Resource Recovery Plant, burned at extremely high temperatures, and the heat is used to generate energy in the form of electricity or steam.
Heat generated by the incinerator goes to neighboring Korea District Heating Corporation and is consumed to heat 20,000 homes in the Mapo area of Seoul. Though the incineration process is typically unpopular due to the risk of discharging highly toxic emissions, the facility is capable of destroying most dioxins and other harmful gases with high temperature and retention time in the incinerator.
The area, where the facility is located, was once a landfill site called Nanji Island, which contained about 92 million tons of garbage.
Nanji Island posed a serious environmental problem as it overflowed with trash and produced methane gas and toxic water. City authorities halted the dumping of trash at Nanji Island in 1993 and transformed it into a so-called ecology park by covering waste with a one-meter layer of impermeable plastic liners and then topping off with soil.
Kim Dong-sik, site manager of Mapo Resource Recovery Plant, stressed the importance of recycling to facilitate waste-to-energy practices.
"Recycling can be the basis of resource recovery. If we don't recycle, incineration becomes difficult and demands the use of auxiliary fuel. Recycling offers optimal conditions for waste to generate heat," said Kim.
Next to Mapo Resource Recovery Center is a hydrogen-fueling station that develops hydrogen from methane from landfill gas.
There are three more hydrogen fueling stations in Seoul, but what sets this station apart from others is that it transforms landfill gas into a clean form of renewable energy. The three stations either rely on city gas or LPG (Liquefied Petroleum Gas) as the main component to generate fuel.
It is the first station of its kind in the world to extract hydrogen from methane as a clean fuel source. The hydrogen station, which started its operation in June this year, draws upon methane that is produced by decomposing waste at the former landfill site, Nanji Island.
The station is capable of producing 720 Nm3 (normal cubic meters) of hydrogen per day, which is equal amount to power a hydrogen-powered car to drive a total of 7,000 kilometers. The station can fuel about 30 cars a day.
Hydrogen is an environmentally-friendly fuel that does not emit harmful air pollutants, and promotes fuel efficiency. Landfill gas- generated hydrogen goes into fuel cells where it is converted into electricity to power vehicles.
According to the Seoul Metropolitan Government, South Korea produced 2.9 million tons of hydrogen in 2009. In its efforts to expand renewable energy production, the country expects this volume to grow 2 percent each year to reach 4.1 million tons by 2030. More than 30 percent of this total is expected to be used to fuel hydrogen-powered vehicles and for fuel cells.
"Seoul is actively pursuing a green car policy that includes hydrogen fuel-cell vehicles. Hydrogen fuel-cell cars would bring a significant impact on air quality as they reduce urban noise and do not emit vehicle exhaust fumes," said Yu Jun-su from the Seoul Metropolitan Government.
"It is the first time in the world to produce highly pure hydrogen by exploiting methane from landfill gas, and use it for vehicles. In this regard, this hydrogen fueling station can establish a leading image globally and has many good sides in terms of resource recovery," said Yu.
