Environmental aspects of geothermal energy

1. Human and the environment.
When the social and economical aspects are developed in a country, the levels of stress in the environmental landscape increased. The rising rates of natural resources consumption and of environmental harm, are one of the principal problems of governments and institutions worldwide. They are seeking for ways to ensure the sustainability of our natural resources.
Todo this, we need to have adequate energy supplies at acceptable cost. This is a prerequisite to social and economic progress. [2]
We must be aware of that the sustainable use of a resource, any type depends on its initial amount, the rate of generation, and its rate of consumption.
Even if the rate of consumption exceeds the rate of generation, energy production can nevertheless be sustainedover some time period dependent upon the magnitude of the difference between these rates and the initial amount of the resource available.
These issues have direct relevance to geothermal systems, particularly in the context of the dimensions of a specific resource. [3]

All energy production changes over the environment and needs some kind of engineering and building activity, which producessome kind of environmental impact. Although geothermal energy is deemed to be a clean energy source, its development may result to some emission of gases and effluent water that must be eliminated. Compared with other energies, like nuclear and fossil fuels, geothermal is a benign energy source. The relative amounts of greenhouse gas emissions are of the same magnitude as most other renewable energysources, such as hydro and solar energy. [5]
In the last years, the attention towards renewable sources of energy production has intensified. There is now an international effort to develop and utilize new sustainable energy to combat the climate change.

2. Key indicators of sustainability
The positive and negative aspects of this environmental impact have to be considered prior to anydecision to develop a geothermal field. The main purpose of the indicators is to reduce the complex and poorly understood problem to a limited number of variables that portend impending changes in the environment to support life and management systems. [9]

The main reasons for the indicators used are:
1. Are useful in describing baseline, actual conditions and performance of a system. They providethe common language for describing a specific system that is necessary for effective and clear communication among stakeholders.
2. The indicators offer a measure of the effectiveness of actions and policies to move a system toward a more sustainable state. Provide objective information in order to find a solution, a treatment or intervention in relation with the principal objective.
3. Might beused to predict the future, because of stochastic processes between human-environment. [9]

We will use them for assessing progress toward achieving a goal.
The key points of sustainability used in this area:
• Environmental aspects. Greenhouse gas emissions.
Air pollution
Water pollution
Land issues
Noise
Smells
Surface disturbances
Physical effects of fluid withdrawal.
Chemicalpollution
Biological effects.
Protection of natural features.

• Availability
• Efficiency
• Water consumption
• Economy
• Social impacts

3. Advantages and Disadvantages of using geothermal energy

• Environmental aspects. Greenhouse gas emissions.
Air pollution: Steam from major geothermal fluids contain between 1.0 and 50 g/kg of non-condensable gases emitted, such as CO2, H2S,NH3, CH4, N2 y H2. [6]
The Co2 emissions are less if we compare it with gas, oil or carbon.
H2S is cause for concern because it causes acid rain.
Emissions of Hg are similar to those produced by coal-fired power stations. [7]

Water pollution: Water quality, water availability and use of water resources, are the possible problems that we can find in this natural resource exploitation.
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