The Republic of Korea appointed 11 fields for new/renewable energy other than petroleum, coal, nuclear, natural gas in the provisions of Article 31 in the Act to Promote the Development, Use and Distribution of New Energy and Renewable Energy.
Renewable energy: solar, photovoltaic, bio-mass, wind, small-sized hydroelectric, geothermy, ocean energy, energy from wastes (8 fields)
New energy: fuel cell, coal liquefied gas, hydrogen energy (3 fields)
Geothermy refers to energy kept by the earth including hot water and rocks existing in the depth of several kilometers in addition to the shallow places in the earth surface. Such hot water is called a thermal spring and the melted rocks a magma.
The geothermal sources are endless as a treasure house of energy continuously generated as long as the sun and the earth are existed.
Sustainable and renewable heat sources
  - Securing stable heat sources from hundred meters underground
- Nearly no change of temperature around the year
Stable heat sources

- Ground temperature is higher in winter and lower in summer than air-heat source.
- No deterioration in the performance of cooling and heating even in the extreme hot or cold weather
- Nearly no change under 15m around the year
- Ground temperature is higher in winter and lower in summer
- Maximizing the efficiency in the cooling mode and heating mode.