Tuesday, October 20, 2009
Renewable duel: Geothermal vs. Wind
Why geothermal energy is at least visible among the other types of Renewables? Is it worse or less competitive in comparison with the others? Surely not. We would like to give some arguments into discussion, which demonstrate positive and negative sides of both - geothermal and wind energy.
One can compare installation costs, cost per kWh of electricity produced, visual impact on scenery, environmental issue as well as other "natural properties".
Initial costs depend on the level of general technology advance as well as the size of market. It is fact that each year installation costs for wind energy decrease, especially since the very recent decade. On the other hand, one wind park is composed of several (many) wind turbines, each with installed relatively expensive technology. The price of one installed MW is about 1 million USD. In addition, in order to exploit the economy of scale, wind park should be in excess of 20 MW. In comparison, developing the geothermal power plant requires about 2-3 times higher initial costs (it depends on fact whether it is smaller or bigger power plant - in case of reaching synergy, the initial costs decrease). Well, this imbalance between geothermal and wind is caused by relatively low level of innovation and technology progress on field of geothermal energy. In line with development of EGS, those initial costs would decrease under the level of installation costs of wind parks - but this is still the issue of the near future.
In case of operating costs (or the price per 1 kWh of produced energy), given to choose better option, geothermal energy leads. The price for single amount of energy produced from geothermal rises up to 3 - 3,5 USD cents. In comparison, 1kWh of energy gained from wind could cost 4 - 6 USD cents.
In addition to previous paragraph, geothermal heat is accessible 24 hours per 7 days. Its average availability is about 90 percent. Wind power plant productivity depends on actual weather situation - simply said whether it is windy or not. Wind turbine cannot guarantee that it will always generate as much electricity as it would be needed.
Not the last advantage of geothermal is the combination of visual and environmental impact. Imagine you are a human that had never seen any wind turbine. Once you see it, probably you would admire it as an symbol of industrial development. But would you choose area near wind park as a destination for vacation or as a place for living? Surely not, if there would be other possibilities. In addition, wind turbine's rotor generates not only electricity, bus noise as well. The mill sometimes kills birds crossing its operational space:
However, most of those problems have been eliminated thanks to technological advance, but the part of them still remains. Regarding geothermal energy, facilities could produce some solid materials, which require disposal. On the other hand, some of those "side products" can be sold and utilized in industry, especially sulphur, zinc or silica. This makes geothermal much more environmental friendly. In matter of visual impact, there is no noise as well as no large area built up with wide-visible industrial facilities.
And the last, but not the least important, is the possibility of exploiting geothermal water as a source of heat utilized in municipality heating systems. This is something that wind power plant could never offer. In conclusion, when EGS is additionally developed, geothermal will become better choice than wind - from any perspective.