Video Transcript
Which of the following statements correctly describe the disadvantages of geothermal power? a) Geothermal power stations can only be built in certain locations. b) Geothermal power stations produce large quantities of sulfur dioxide, which is damaging to the environment. c) Geothermal power stations are only efficient enough to be economically viable in cold climates. d) Geothermal power stations produce large quantities of carbon dioxide, which contributes to climate change. And e) Geothermal power stations are expensive to build relative to the amount of power they produce.
Alright, based on the way our question is worded, we’re going to need to evaluate each one of these statements to see if it correctly describes a disadvantage of geothermal power. Our first statement says that geothermal power stations can only be built in certain locations. Now, the way these power stations work is they access heat energy underneath the surface of the Earth. They do this using wells that are typically several kilometres deep.
Geothermal power stations work best when they’re built over areas of the Earth that are very thermally active. These include places where there’s been volcanic activity or where tectonic plates within the Earth have been in motion. So it’s true. Geothermal power stations are only built in certain locations. They’re built in places where there’s lots of underground activity.
Moving on, the next option says that geothermal power stations produce large quantities of sulfur dioxide, which is damaging to the environment. Indeed, sulfur dioxide can cause the precipitation of acid rain, which is very damaging to the environment. However, when geothermal power stations operate, they don’t produce large quantities of this pollutant. In fact, during normal operations, these power stations give off almost no emissions. So it’s not true that they produce large quantities of sulfur dioxide.
The next statement says that geothermal power stations are only efficient enough to be economically viable in cold climates. The idea being put forth here is that there needs to be a significant temperature contrast between the temperature of the ambient environment of a geothermal plant and the temperatures it’s able to access using its well. But this ignores the fact that heat energy, as long as we can get it using our well, is heat energy. It doesn’t require a contrast in temperature or energy level in order to be useful to us. As long as our power station is in a spot where it can draw enough heat energy from within the Earth, the average temperature of that climate or that location isn’t important. So we’ll cross this off as a description of a disadvantage of geothermal power.
Our next statement says that geothermal power stations produce large quantities of carbon dioxide, which contributes to climate change. It’s true that carbon dioxide as a greenhouse gas helps to trap heat within Earth’s atmosphere, thereby contributing to climate change. But it’s not true that geothermal power stations produce large quantities of this gas. Instead, as we saw earlier in the case of sulfur dioxide, when geothermal power stations are operating, they produce essentially no pollutants.
Lastly, option e says that geothermal power stations are expensive to build relative to the amount of power they produce. One of the significant costs of a geothermal power station is in drilling the well it uses to access Earth’s heat. And indeed, for the amount of heat energy that’s harvested and converted to electrical energy, the plant overall is very expensive. So this disadvantage of geothermal power stations is accurate. In summary then, the disadvantages of geothermal power are that these power stations can only be built in certain locations and that they’re expensive to build relative to the amount of power they produce.
