There are quite a few energy sources in the world, with some sources producing energy at a greater cost than others. Comparing various energy sources can help consumers make wise choices when it comes to their own energy consumption. Both natural gas and geothermal energy are used to heat structures and even generate electricity. But the two energy sources are quite different from one another. To make an educated decision about which source to use, it’s necessary to understand both their similarities and differences.
It’s important to remember that natural gas is a fossil fuel, just like coal and petroleum. On the plus side natural gas is considered the cleanest of the fossil fuels. Natural gas comes from plants and animals that were buried in layers deep in the Earth. As these decomposing organic materials were exposed to heat and pressure from the Earth they eventually turned into natural gas. The energy in natural gas comes from the carbon the plants and animals obtained from the sun when they were still alive.
Natural gas must first be extracted from the Earth, which involves drilling to reach the natural gas deposits deep in the ground. Of course drilling can destroy the natural habitats for both animals and plants in the area and lead to groundwater pollution. Once the natural gas has been extracted from the ground it is transported to gas plants. Impurities like carbon dioxide, helium, hydrogen oxide and even water moisture are filtered out of the natural gas. The natural gas is transported through pipelines to the various buildings where it is to be used for energy purposes.
The most common use for natural gas in many areas is for heating buildings. The natural gas is combusted in a furnace to heat the air, which is then transported around the building through a series of ducts. In some buildings the natural gas is combusted to heat the water in a boiler. The water is then sent to various baseboard heaters, radiators or radiant heat panels in various rooms.
Power plants can also use natural gas to produce electricity. This is done by combusting the natural gas so that it heats up water in an enclosed area. The water eventually turns into steam that turns one or more turbines. The spinning turbines are attached to a generator that turns the kinetic energy of the spinning turbines into electricity.
Of course burning natural gas does produce pollution. Compounds released from the burning of natural gas include carbon dioxide, nitrogen oxides and even methane when the gas is not burned all the way. As with other fossil fuels, the carbon dioxide released has been stored for thousands of years, resulting in a net gain of carbon dioxide in the atmosphere and contributing to global warming. Still, burning natural gas does not produce as much pollution as burning other fossil fuels. For example, a power plant that uses natural gas results in about half the amount of carbon dioxide emissions, a third of nitrogen oxides and one percent of the sulfur oxides that are produced by a coal burning power plant.
Natural gas is used in a variety of residential applications. These include furnaces, boilers, clothes dryers, stove ranges and water heaters. Natural gas can also be compressed and used to fuel vehicles, which results in fewer emissions than petroleum.
In contrast, geothermal technology can only be used in residential applications to heat a building with radiant or steam heat or to provide hot water for cooking and bathing.
Unlike natural gas, geothermal energy is a renewable resource. Geothermal heat comes from magma embedded deep under the Earth’s surface. Wells are drilled into the Earth to capture the hot water or steam that is produced by the magma. In some applications, a system is actually designed to send water down the well where it will come into contact with either magma or hot stones buried deep in the ground, producing steam that rises back out of the well. Since the Earth is constantly hot geothermal energy is a source of energy that can continually be used without risking depletion. The only resource problem might arise from sending water into the Earth to generate steam.
One problem with geothermal energy is that the magma ideally needs to be located relatively close to the Earth’s surface for it to be of much use for generating electricity. This means geothermal energy is more economical to use in some areas versus others. In other words, buildings that are not located in areas with significant geothermal energy located near the surface cannot economically take advantage of the alternative energy source.
Another key difference between geothermal energy and natural gas is pollution and environmental impact. Since nothing is combusted to produce geothermal energy, there is no air pollution produced. Most systems that send water down a geothermal well to produce steam are set up to capture the water vapor and reuse it over and over. Some of the water evaporates and cannot be recaptured, but it is a small amount of the water and so presents only a minimal strain on water resources. The ground water in an area might be negatively affected by the drilling of geothermal energy wells and even the extraction of hot water or steam from deep within the Earth, but such ground water contamination is preventable with certain safety practices followed properly. Water extracted from the ground for geothermal uses is usually sent back into the Earth via a second well set up expressly for this purpose.
A geothermal energy system in a building is generally more durable than furnaces or other natural gas appliances. The lack of regular maintenance makes geothermal energy more compelling as an energy source. Of course going with geothermal heating means that you will need to use other energy sources for drying clothes or cooking food on a stove, meaning you might still use some natural gas.
One of the most compelling reasons to consider using geothermal energy in a structure versus natural gas is cost of operation. While it might cost more to have a geothermal system installed, over time the lack of utilities costs outweighs the initial cost.