How practical is geothermal energy?

Geothermal energy attracts plenty of interest on global energy market, despite the fact that this energy source is still far off from turning its abundant potential into a more significant role in generating clean electricity. Geothermal energy has abundant resources that are estimated to be larger than those of fossil fuels and uranium combined. There has been a variety of different studies aimed to determine how much usable geothermal energy is available, and the consensus seems to indicate there is enough resources to last somewhere between 500,000 and 1,000,000 years. From our perspective this certainly looks like limitless form of renewable energy

Geothermal power is mostly used to generate electricity in geothermal power plants. The deciding factor for most companies when building any new power plant are the construction and maintenance costs. If we compare geothermal power plant with the one fired by fossil fuels we can see that the cost of operating the geothermal plant is pretty much competitive to that of the plant that uses fossil fuel to power the turbines. The obvious distinction between the two is that the emissions that fossil fuels give off are full of pollutants, which is not only one of our major health concerns but also contributes to climate change, while geothermal energy is connected with minimum amount of harmful emissions.
The best example on how to really benefit from geothermal energy comes from Iceland. There should be no surprise here because harnessing geothermal energy seems logical and natural with so many geothermal springs on the island. In fact, with all the volcanic activity they have one might say that Iceland is one big geothermal spring. Currently about 75% of Iceland's power comes from geothermal energy and they are striving to be the first county to be 100% renewable by primarily focusing on geothermal energy and to the lesser extent on other renewables such as hydro and wind.

In order for practically and commercially harness geothermal energy developers must first find an adequate site known as a geothermal spring. Once a promising site is found, drilling is needed to determine if there are sufficient geothermal resources below. How deep you have to drill is not the same in all case, the basic rule is that for every 100 meters you go deeper into the earth’s crust, the temperature of the rocks increases by 3 degrees Celsius (5.4 degrees Fahrenheit). Once an appropriate geothermal spring has been located, geothermal power plant is constructed and the generation of clean electricity can start.

The vast majority of currently harnessed geothermal springs are found along the major tectonic boundaries, which represents the area where the majority of volcanic activities and earthquakes are concentrated. The most active volcanic areas have been located along the so called "Ring of Fire"

There are still certain drawbacks that prevent geothermal power from being widely used source of energy. For instance, geothermal springs are found only in limited number of areas and the technology to harness geothermal energy is yet to become commercial though EGS (enhanced geothermal systems) provide a certain level of optimism that the feasibility of building new geothermal power plants could be spread to many new areas all over the world.

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Coal and gas usage continues to grow on global level

The oil is still the world's most important energy source but the use of coal and natural gas continues to grow in significance, according to new study conducted by the Worldwatch Institute. According to recent numbers the global usage of coal increased 5.4 percent in 2011, to 3.72 billion tons of oil equivalent, while natural gas use grew 2.2 percent, to 2.91 billion tons of oil equivalent.

Both coal and natural gas remain primary sources for electricity generation worldwide and they are also often used as substitutes for one other, meaning that in order to get more precise numbers their trends need to be examined together. The large part of total coal consumption is used for electricity generation, with smaller amounts being used in steelmaking industry. The global coal consumption primarily grew because of rising demand in China and India. 

The coal share in the global primary energy consumption was 28 percent in 2011 which represents the highest percentage since the International Energy Agency began keeping statistics in 1971.

China, the fast rising economic giant, alone accounted for nearly half of all coal usage in 2011. India is the second largest contributor to rising coal demand and is the world's third largest coal consumer, after surpassing the European Union in 2009. The United States remains the second largest coal consumer, though it has to be said that U.S. demand decreased by around 5 percent in 2011 and its decline continued in 2012, particularly because of the shale gas popularity and the abundance of cheap natural gas.

Coal production, as well as consumption, is concentrated mainly in China because coal still remains the main fuel behind the China's rapid economic growth.  The United States however still holds the largest proved coal reserves in the world, with 28 percent of the global total, followed by Russia at 18 percent, and China at 13 percent.

Global consumption of natural gas grew at a slower rate than coal - 2.2 percent - to reach 2.91 billion tons of oil equivalent in 2011. Natural gas consumption grew in all regions except in the European Union, which experienced a 9.9 percent decline in natural gas consumption, mostly because of the struggling economy and high natural gas prices.

Natural gas accounted for nearly 23.7 percent of global primary energy consumption in 2011, experiencing a very slight decline from 23.8 percent in 2010. The natural gas consumption increased most significantly in East Asia, primarily in China (21.5 percent) and Japan (11.6 percent).

Natural gas production increased at a higher rate than consumption, by 3.1 percent, reaching 2.96 billion tons of oil equivalent in 2011. The United States and Russia are largest natural gas producers in the world, accounting for nearly 40 percent of the world's output in 2011.

Whether the strong growth in the global coal and natural gas sectors will continue depends on several different factors. Demand for coal would likely decline with the introduction of new technologies in the power sector, or with the adoption of clean energy policies aimed to reduce the environmental and health impacts of coal combustion. Also, the increasing global concern about greenhouse gas emissions and climate change would likely lead to a greater transition from coal to natural gas. In relation to natural gas there have been environmental and other concerns about hydraulic fracturing as well as the possibility that cheap shale gas might prevent the further development of renewable energy sector.

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