Last time I talked about how we’re going to power our portable objects such as mobile phones, laptops and cars. This week I want to discuss a stationary but very powerful technology that’s actually very “down-to-earth”
Geothermal power is extracted from the heat stored in the earth from it’s original formation. It can also be seen on the surface in the form of hot springs. This very old technology is now more than ever being looked at as a means to usher in the inevitable end of oil. The number of new geothermal projects in the United States alone has risen 25 percent since last August.
That number sounds very impressive, but geothermal still only counts for a very small percentage of the world’s energy output. 35% of it is from the United States but it only counts for less than 1% of their total energy.
So why the sudden interest? Well as I mentioned the worlds oil supply continues to deplete. We have reached peak oil (according to some) and deposits for this traditional power source will be more and more difficult to find. Another reason is the advancement in the technology. It used to be that in order for geothermal power to be of any major use, you’d have to live near one of Earth’s major fault lines to acquire the heat in a natural convective method. Enhanced Geothermal Systems do this through hydraulic stimulation. When natural cracks and pores will not allow for flow rates, the permeability can be enhanced by pumping high pressure cold water down an injection well into the rock. The injection increases the fluid pressure in the naturally fractured granite which mobilizes shear events, enhancing the permeability of the fracture system. Water travels through fractures in the rock, capturing the heat of the rock until it is forced out of a second borehole as very hot water, which is converted into electricity using either a steam turbine or a binary power plant system. All of the water, now cooled, is injected back into the ground to heat up again in a closed loop. These technologies are impressive enough to garner the attention of internet giant Google. In 2008 they invested 10 million dollars to further research this potential source.
That being said there are still plenty of untapped traditional geothermal sources and may be the safer bet in such a shaky economy. So far, it’s one of the only commercially proven renewable power source that can deliver baseload power ( minimum demands based on customer requirements )
To give you one example of how geothermal power can help. A company called Ormat, located in Reno, Nevada produces enough geothermal power to run that city. When you think of the electricity used to charge the entertainment landscape of Reno, it makes you wonder why we aren’t investing more heavily into this natural and renewable power source.