Written by Elizabeth Kepl, ESLLC 2015-2016
Geothermal energy is one of the most sustainable energy sources earth provides us. The water used for geothermal energy is pumped down into the earth and the heated water and steam is pumped back up to go through a turbine and create electricity in a generator. This is then pumped to a cooling tower and returned to the earth. Most of these geothermal systems run in a closed-loop water system which means there is no water taken away or being added to this system. The water is reused every time the cycle runs. The water from the ground that is pumped up contains high levels of sulfur, salts, and other mineral, but since most are closed-loop systems there has been no cases of water contamination from geothermal sites. This type of energy can also use different fluids for heating, such as geothermal fluid or non-potable treated wastewater. Overall this type of energy is very water conservative.
In a closed-loop system there are no air emissions because the steam created from underground heating is cooled and pumped right back into the ground, so the minerals that pollute the water are not exposed to the atmosphere. In the rare case there is an open-loop system the emissions can include hydrogen sulfide which gives off a “rotten egg” smell, carbon dioxide, ammonia, methane, and boron. This is where the push to closed-loop systems is huge. There would be zero air pollutants if all of the geothermal systems were closed-loop systems, which most are. Sulfur dioxide forms acid particles which contribute to acid rain, can cause lung disease, damages crops and acidifies bodies of water. The emissions of this are 30 times lower per megawatt-hour than coal plants so even if open-loop systems had to be used they would still be more environmentally friendly.
Considering this, geothermal energy provides a clean and sustainable source of energy from closed-loop systems. This is where the push for closed systems instead of open systems must be accounted for. If in a geological hot spot then this type of energy should be used instead of other energies, but only in a closed-loop system. The energy that is produced creates no pollutants because it is contained to that closed system so the environment is not impacted. In this case we are using our resources in a safe and environmentally friendly way to provide energy by not harming or taking away the earth’s elements.