Science of Geothermal – Video
Summary
Science of Geothermal Video: How Earth Heat Can Power and Heat
This geothermal energy video explains how Earth’s internal heat can be used to produce electricity, heat buildings, and in some cases help with cooling. Dr. Scott W. Tinker introduces geothermal by defining the term itself. Geo means Earth and thermal means heat, so geothermal energy is energy from Earth’s heat. The video then guides students through three main ways geothermal energy is used, and it emphasizes why availability, cost, and location determine which methods are most common.
The first type of geothermal is the most powerful but also the rarest. In regions near plate boundaries and geologic hotspots, heat from Earth’s interior rises close to the surface. This can superheat groundwater, creating hot water and steam that can be accessed by drilling wells. Students learn how this hot water and steam can be circulated through radiators to heat homes and even entire cities. The same heat source can also drive steam turbines to generate electricity, using systems similar to other steam-based power plants. The video notes that this method is limited because hotspots and plate boundaries are not common in most regions.
The second type is often called enhanced geothermal systems. Vertical wells are drilled and hydraulically fractured, similar to oil and gas drilling. Water is injected, heated underground, and then produced back to the surface. Students learn that this method could expand geothermal electricity generation to more locations, but it remains experimental and expensive compared to the energy it returns today.
The third type is the most widely available and focuses on heating and cooling buildings. Just below the surface, Earth stays at a nearly constant temperature. The video explains that by burying a closed loop of pipe in shallow trenches or deeper vertical wells, water can circulate and take on the ground temperature. That water is then used in a building system to help maintain indoor comfort. These systems cost more to install but can cost less to operate, last longer, and reduce emissions compared to conventional heating and cooling.
This geothermal energy video works best with the Science of Geothermal lesson and is intended for use with the vocabulary and quiz activity.
Transcript:
[Dr. Scott W. Tinker] Geo means Earth and thermal means heat, so geothermal energy is just the heat of the Earth which we use to make electricity or heat and sometimes even cool buildings. There are three main types. The first is by far the rarest but the most powerful; at geologic plate boundaries like Japan or California or geologic hotspots like Iceland, the heat of the Earth’s interior comes very near the surface and it super heats the groundwater. We can drill wells to tap into this hot water and steam, which can then be circulated into people’s homes and through simple radiators. Whole cities can be heated this way or it can be used to drive steam turbines similar to those and other kinds of power plants to make electricity. This is an amazing energy source but since hotspots and plate boundaries are not widespread, it’s not widely available. There’s a second way to get hot water from the Earth. Vertical wells are drilled and hydraulically fractured much like an oil and gas well. Water is pumped in here where it’s heated and produced from a well here. Some think this technology has the potential to generate significant electricity worldwide, but today it’s experimental and therefore expensive for the amount of energy that it returns. The last king of geothermal can be done almost anywhere. Just below the surface, the Earth stays a constant temperature. In the U.S. that’s between 60 and 70 degrees. If we bury a long, closed loop of pipe either in trenches or vertically to as little as 200 feet and then circulate water through it, it takes on the temperature of the Earth. We then pump it into a building and blow air across it like a regular heating or AC system. This keeps the building at a constant temperature whether it’s hotter or colder outside. These systems are twice as expensive to install as conventional heating and cooling, but they’re cheaper to operate, longer-lasting, and produce fewer emissions. That means this most widely available form of geothermal energy may be the most adopted of all three.