South Korea failed to reach its target for the development of clean, renewable energy sources last year, the government said Thursday, again raising questions over what many have been an unrealistic goal to cut the country\'s greenhouse gas emissions by 30 percent. Under the so-called renewable portfolio standards (RPS), introduced late 2011, all major electric power companies in the country were required to produce 2 percent of their power supplies from renewable energy sources in 2012. They are required to gradually increase the portion of power generated from renewable energy sources to 10 percent by 2022. The power companies, however, failed to reach the target, only fulfilling 64.7 percent of their requirements last year, according to the Ministry of Trade, Industry and Energy. Such a failure apparently comes as the country has yet to fully develop renewable energy sources. In 2012, the power companies fulfilled 95.7 percent of their requirements for power generation from solar energy, which is a relatively well developed and industrialized field, but only 63.3 percent of quota from non-solar energy sources. Still, the failure is raising alarms over the country\'s ambitious goal to voluntarily reduce its greenhouse gas emissions by 30 percent in 2020 from its business-as-usual levels . The goal, announced in 2009 under the former Lee Myung-bak administration, is also facing difficulties due to a growing public demand to cut the country\'s dependence on nuclear power, currently the largest source of the so-called clean energy here that supplies about 30 percent of the country\'s electricity consumption. The companies that have failed to fulfill their requirements will be fined, though the ones that had legitimate or unavoidable reasons for their failure will have their fines reduced by up to 30 percent, the ministry said. The ones that have failed without any legitimate reason can be imposed an additional fine of up to 50 percent.