3.2        Social Implications

As the economic benefits of using geothermal energy remain in the region it helps rural areas to develop without environmental pollution. It also contributes to the reduction of energy import; therefore it is especially important for those nations (particularly the developing ones) which depend heavily on fossil fuels such as oil, coal or natural gas. For example in Tibet, where fossil fuels are not available, the Nagqu geothermal field could provide a useful energy source for the local population. In Iceland, New Zealand, Japan, Kamchatka and the west of North America these sources are already available to serve local demands.

Geothermal power plants installed in remote locations can raise the standard of living and the quality of life by bringing electricity to people far from the "electrified" population centres. This is because the technology is suitable for rural electrification and mini-grid in addition to national grid applications.

In summary, the most obvious advantage of geothermal energy from a social point of view is that it reduces energy import and benefits local communities, offering modular, incremental development and village power to remote sites.

3.3        Environmental Implications

Geothermal energy is clean and safe. Although plants release some CO₂ and H₂S, the emission level is much lower than that of fossil fuel combustion. Atmospheric emissions average only about 5% of those discharged by fossil based plants of equivalent output.

Besides its apparent environmental benefits, geothermal energy utilization may also have some adverse impacts, which need to be balanced against its obvious advantages over fossil fuels.

 

 

 

 

 

 

Geothermal fluids usually contain gases such as carbon dioxide (CO₂), hydrogen sulphide (H₂S), methane (CH₄), as well as dissolved substances, for example, sodium chloride (NaCl), boron (B), and in some cases traces of arsenic (As) and mercury (Hg) - a source of chemical pollution if discharged directly into the environment - whose concentrations usually increase with temperature.

The wastewater produced by geothermal plants is hotter than the surface environment, and can therefore be a potential source of thermal pollution. The relatively high salt content can also significantly spoil the quality of ground and catchment waters.

However the common practices of re-injecting geothermal fluids, as well as gas extraction or chemical conversion eliminate all these impacts on aquatic life and - compared to traditional power production systems – result in emitting far less pollutants.

It is a much-debated question whether earthquakes can be induced by geothermal fields or not. It has been pointed out that geyser fields are situated where earthquakes are natural phenomena. Sometimes re-injection of fluids has an impact on fault lines, which result in pressure concentration. It might lead to microseismic activity, especially where the fluid is re-injected into a different stratum than that of production. Though not a form of pollution, increased seismic activity certainly alters the environment. Rural areas where buildings have fragile construction are especially prone to damage caused by seismicity.