Currently, energy-related issues of the future are more interesting to discuss. The reason, in addition to non-renewable resources, is increasingly thinning due to excessive exploitation, as well as the implications of fossil fuels that greatly affect the increase of carbon emissions and greenhouse gases.

The world was competing in developing renewable energy. Several countries are working together to develop and transfer the use of fossil energy to renewable energy. Iceland is one of them, as a country with huge geothermal potential, Iceland utilizes geothermal for power generation.

Aceh is the region with the second largest geothermal potential after the United States. As many as 40% of the world's geothermal potential is in the territory of Indonesia. Generally, geothermal sources in Indonesia are associated with high topography volcanoes (volcanic Stratos), because geographically Indonesia is on the Pacific Ring of Fire or Ring of Fire.

Some areas in Indonesia through which the Ring of Fire of the Pacific among them stretch from Sumatra, Java, Sulawesi, Maluku islands, to the Pacific Ocean basin. This area is better known as the Pacific Belt.

Thus, it is possible that there are geothermal sources in the region within the Pacific Ring of Fire. In the region, there are components of geothermal sources such as heat source, reservoir rock, inflow, and outflow/lateral flow or up the flow. Simply put, illustrations of geothermal systems are associated with volcanic environments.

Basically geothermal is defined as the natural heat that comes from within the earth and is formed due to radioactive decay. In general geothermal is a natural heat transfer process in the earth, from the heat source to the reservoir. The heat transfer occurs by convection and conduction

Geothermal potential can be seen from the emergence of existing manifestations on the surface. According to Wohletz and Heiken (1992), geothermal manifestation is the release of geothermal fluid from the reservoir to the surface through fractures or permeable zones.

Geothermal manifestations may be water such as hot springs, warm springs, hot water pools, and warm water pools, or they may be fumaroles and geysers, depending on the reservoir temperature and the fluid flow rate of the geothermal. In addition, deposits such as sinter silica or travertine can form on geothermal systems.

Surface geothermal manifestations can be used in determining the condition of the reservoir that lies beneath the surface. There are two types of manifestations on the geothermal surface, which are the active manifestations and fossil manifestations. Active manifestations have a fluid output, whereas fossil manifestations are rock alterations.

Manifestations on the surface are common manifestations of geothermal with a system of steam and water dominance. The reservoir temperature for the water dominance system is approximately less than 90 oC for low temperatures, 90-150 oC for intermediate temperatures, and 150-240 oC for high temperatures.

The temperature of the hot springs alone will not exceed the boiling point of water at the elevation level of the springs. Examples of water domination systems are found in countries such as Indonesia, Taiwan, Japan, the Philippines and New Zealand. Surface geothermal manifestations are generally an exploratory target for understanding reservoir conditions.

The steam dominated reservoir system is generally characterized by steam amounts of more than 85%. The steam system is an ideal geothermal source, but not much more than the water dominance system.

Hot springs are the most visible manifestation of water domination systems. The springs group is usually a direct output to the geothermal system and is used as a guide for drilling sites at the exploration stage.

However, sometimes these springs are the result of an output that has flowed several kilometres away from the centre of the reservoir. The chemical analysis of hot springs will provide information on the level of mixing between groundwater and water from geothermal reservoirs.

If water chemistry analysis shows that the mixture content of groundwater with hot springs is very small, it can be stated that hot springs are directly above the source of heat and reservoir temperature can continuously be obtained through the drilling process.

The history of geothermal utilization is not known much besides its utilization as a power plant. Though geothermal can be utilized directly or indirectly. The indirect utilization of geothermal is generally as a power plant.

Direct use includes hot water baths, industrial use, agriculture, and aquaculture, to warming up the room. Geothermal exploration and exploitation are a concern from time to time, both conventionally and using the most up-to-date technology.

The development of geothermal energy exploration technology is very rapid. For example, in the past heat extraction only ranged in depths of 1 to 3 km. However, in Iceland today, the depth of drilling of wells that can be achieved for power plants is around 5 km.

Currently also under development EGS (Enhanced/ Engineered Geothermal System) or host dry rock, which is a geothermal extraction technology that aims as a power plant.