Monday, January 12, 2015
Environmental Impact of Geothermal Energy
Strong and weak aspects one can identify when studying various issues. Let's summarize impacts of geothermal energy. In this shot we will write about impact on environment, the next one will be focused on human health impact.
The linguistic origin says that „Geothermal“ represents the heat coming from Earth's depths („Geo“ like Earth, „thermal“ like heat). It means that this source of energy is natural and this heat is primary one. In comparison for example with fossil fuels, there are no additional steps or „mid-steps“ required in order to make and obtain heat. In previous article we wrote that according various estimations, Earth accumulates heat that would be enough to satisfy global energy demand for more than 10 billion years (see this link). In addition, this heat is accumulated either by adsorbing sunshine through surface or by happening specific chemical and physical reactions in Earth's solid iron core. Dangerous products of these reactions (UV radiation, dangerous gases, nuclear elements etc.) remains either in space, outside the ozone layer of Earth's atmosphere, or enough deep in proximity of Earth's core, which means deeper than magma. Therefore creating of this heat doesn't represent relevant danger, no question about it.
There are just three main objections towards geothermal energy:
Drilling issue is comparable with mining issue in matter of obtaining power sources for coal or nuclear power plants. On the other hand, geothermal wells do not require such a long diameter than mining s ahaft or the colliery. It is true that geothermal wells could be deeper than mining shafts, but altogether they require less capacity of soil to be removed.
Cooling the Earth is being mentioned as the second objection. Yes, if we exploit more heat than is capable to be renewed, by time the geothermal well produces ever colder water stream and becomes comercially uneffective. This can be resolved by better customizing EGS approach (more about EGS on this link).
Water issue becomes step by step of an ever higher political priority. Climate change means also the change of global water regime. On the other hand, operating geothermal wells is managed like closed water loop, so there can be no question about wasting the water sources.
In conclusion, environmental impact of geothermal energy depends on how it is being exploited and which approach is taken. But geothermal plants in general does not burn fossil fuels or coal in order to produce electricity. In comparison with „traditional“ power plant, it produces just 1 percent of CO2 emission in contrast with incineration of fossils. In addition, U.S. Environmental Protection Agency (EPA) adds regarding geothermal heating systems (secondary utilization of geothermal power) that geothermal heat pumps are the most energy-efficient, environmentally clean, and cost-effective systems for temperature control. Altogether, geothermal energy represents clean modern solution for growing energy demand as well as for steps against climate change.