Construction rigs tackle fine dust

An excavator at a waste recycling facility in Gumi, North Gyeongsang Province, is powered by an electric motor that SEAEF installed after removing the machine's original diesel engine. / Courtesy of SEAEF

Electric-motor excavators tested as rising eco-friendly machinery

By Ko Dong-hwan

Diesel-engine vehicles have long been blamed as a major cause of fine-dust air pollution now rampant in Korea, but a cleaner alternative is being tested in Daegu.

The city office announced on Apr. 17 a demonstration project to replace aged excavators' diesel engines with electric motors. The Ministry of Environment and the city are splitting the 750 million won ($658,000) cost of the project that will replace Daegu-registered excavators' diesel engines graded Tier 1 or under with motors consuming no diesel fuel.

Applicants, required to use the upgraded rigs in a fixed working area, will receive 40 percent of the replacement motor cost ― 45 million won for a 30-ton machine in general ― or up to 16.5 million won as a subsidy.

"This kind of project has never been put into practice in Korea," Kim Hong-tae, from the Environment Policy Department of Daegu City Office, told The Korea Times. "The environment ministry put funds into other previous projects to reduce air pollutants, like installing diesel particulate filters or incentivizing scrapping of aged vehicles. But after the ministry reckoned that excavators contribute significantly to the growing fine-dust pollution in Korea, it has launched the latest bid as a trial."

The central government already subsidizes engine upgrades for construction machines, replacing diesel engines for Seoul-registered machines with engines of the higher Euro or Tier grades ― engines that passed stricter emission control standards introduced in Europe and the U.S., respectively. But they are still internal-combustion engines that burn fuel.

SEAEF's compound in Daegu. / Courtesy of SEAEF

A few companies in Korea have shifted the paradigm in a greener way, promoting electric motors over diesel engines for excavators. And the motors have some definite selling points ― from customer satisfaction with maintenance cost savings to maximizing user comfort and helping reduce air pollutants.

"A big diesel excavator with 20,000 cubic centimeters of torque fumes exhausts as much as 50 one-ton trucks combined," said Lee Han-gi, founder of SEAEF, a Daegu-based electric motor specialist that introduced the engine replacement technique in 2008 and has a related patent. "When its engine is replaced with an electric motor, it makes zero exhaust, zero noise, has zero jolts and the maintenance cost is cut down by 80 percent." He is now developing the same idea for loaders.

"An electric motor is almost semi-permanent, allowing the machine to run up to 20 years without a single repair, which saves tens of millions of won compared with its diesel counterpart that has a limited lifespan and requires an overhaul every one to two years. It can also bring the same amount of horsepower as its diesel predecessor."

The company's outdoor compound in the city's industrial district in Horim-dong is filled with tens of heavy machines in various stages of engine transplant and a heap of ripped-out diesel engines. Lee has fixed more than 200 excavators so far, many of them weighing over 30 tons.

He embraced the ministry's latest project but complained it should have been introduced earlier for the sake of the owners of about 137,000 excavators registered in Korea as of March 2016, most of whom are cash-strapped after paying for them with high-interest loans.

"The owners seldom replace their rickety diesel engines because of a financial burden," said Lee Dong-choon, the firm's director. "The subsidy from the latest project is not enough but will certainly encourage the operators to participate, which will reduce a tremendous amount of fine dust."

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The prediction goes in tandem with what has been said in the media since last year that over 454,000 construction machines in Korea ― from excavators and forklifts, to dump trucks and concrete-mixing trucks ― are a major source of fine dust, ultrafine dust and nitrogen oxide that increasingly fills the sky.

The Seoul Institute's 2015 report on heavy equipment's role in the city's noise and air pollution revealed the machines produced 31 percent of fine dust, 32 percent of ultrafine dust and 17 percent of nitrogen oxide. A report analyst said heavy equipment had higher engine output than other diesel vehicles, producing more fine dust.

"The more engines are used, the more air pollutants construction machines exhaust," the analyst said. "Besides, they are generally used longer than other diesel vehicles. It is why measures to cut down heavy equipment's exhausts are imminent."

In October 2015, the central government banned six types of construction machines with maximum engine outputs of 560 kilowatts, unless they passed the Tier 4 standard. A year before, three other types of heavy equipment were required to pass the Euro 6 standard. The authority also subsidized some 230 machines, replacing their Tier 1 diesel engines with Tier 3 ones.

But such efforts are just scratching the surface of the nearly half-million legion of diesel construction machines: over 55 percent of them aged 10 years or more were not graded and off the authority's radar. Users also complained about installing diesel particulate filters because it cut the machines' horsepower.

"Finding solutions for fine dust from construction machines has been difficult because they particularly require a high engine output," an automotive engineering professor from Daeduk University said. "Nonetheless, users have had no other options but diesel-running equipment to meet that need."

SEAEF Director Lee Dong-choon shows the inside of an excavator at the company compound. The diesel engine was removed, to be replaced with an electric motor (inbox). / Korea Times photo by Ko Dong-hwan

For now, electric-motor excavators are the closest to the solution. While being eco-friendly, they are cost-effective, quiet and as powerful as diesel machines. Acknowledgement of that brought together for the first time Daegu, the environment ministry and a state-funded private machinery parts recycling researcher to come up with the city's latest engine replacement project.

"About 15 to 20 percent of construction work in Korea occurs in a fixed working area such as scrap metal recycling yards or waste management facilities, and they are concentrated within urban regions," said Choi Byung-woon, Technical General Director at the Korea Construction Equipment Parts Remanufacture Association, based in Gyeongsan, North Gyeongsang Province.

"Heavy equipment there is noisy and costly to maintain, with consistent fueling and repairs, so more people get around engine upgrades with electric motors."

He estimated there are almost 2,000 electric-motor excavators in Korea, rigged and new from assembly lines.

"Major firms like Hyundai Industries and Doosan Infracore sell 30-ton electric excavators for as much as 250 million won each but many interested cannot afford them," he said. "They instead choose to replace their diesel engines with electric motors for just 45 million won."

The central government has invested 5.2 billion won in the association over the past three years after seeing the research group's recycling works ― disassembling aged construction machines to parts and remaking them with up to 90 percent of original performance ― helped reduce fine dust and provided jobs. It is the third arm of the nation's remanufacturing industry approved in June 2016 by the Ministry of Trade, Industry and Energy, following those for auto parts and print cartridges established in the early 2000s.

The association was founded by 10 innovative construction machinery parts specializing firms, including SEAEF. It will move into the Gyeongsan Knowledge Industry District, a 2.6 million-square-meter business park that will be completed and running by June 2018, built by the Daegu-Gyeongbuk Free Economic Zone Authority.

Working with the central government to save energy and reduce environmental pollution, the group focuses on vitalizing the Korean remanufacturing industry that started late compared with advanced nations like the U.S. and Japan.

"For now, we need electric-motor excavators," Choi said.