To understand geothermal energy, imagine having a fireplace nearby, one which never goes out. The fire we speak of exists at the core of our planet. But let’s look at geothermal energy advantages and disadvantages and more geothermal energy basics for a deeper dive.
Earth’s Geothermal Energy Basics
The temperature at Earth’s core measures close to 7200 degrees Fahrenheit. As you might imagine, such a high temperature can produce extraordinary amounts of sustainable energy and untold gigawatts of electricity. Technically speaking, geothermal energy is regarded as a renewable source of energy which can produce energy for as long as our planet exists.
According to the Geothermal Energy Association (GEA), the geothermal power industry reached about 3,442 MW at the end of 2013. Add to this about 1,000 MW of planned capacity additions under development and about 3,100 MW of geothermal energy resources under development. The industry’s US additions in 2013 added about 85 MW of new capacity at new and refurbished power plants in Utah, Nevada, California, and New Mexico.
The GEA’s 2014 Annual U.S. & Global Geothermal Power Production Report states, “The international geothermal power market is booming, growing at a sustained rate of 4% to 5%. Almost 700 geothermal projects are under development in 76 countries. Many countries anticipating the threats caused by climate change realize the values of geothermal power as a baseload and sometimes flexible source of renewable energy.”
Upper estimates show a remarkable worldwide geothermal energy potential of 2 terawatts (TW), though — much more than we are on track to tap.Then why aren’t we producing such energy? Let’s take a closer look at some of the advantages and disadvantages when it comes to producing geothermal energy for home, business, or city.
Using geothermal energy is not a new practice. Writing for Kids Discover, Robin Koontz describes how our ancient ancestors knew about the earth’s heat and used it to heat dwellings, cook food, and bathe.
Today, there are two ways in which geothermal energy can be used.
First, heat from the Earth’s surface can be used with geothermal heat pump systems. An air delivery system using ducts, along with a heat exchanger buried in the ground, can pump heat into a home or building. The heat pump can also work in the summer, removing heat from inside the building into the heat exchanger. That hot air can also be used to provide hot water.
Secondly, there is the option of electricity, writes Koontz.
“Electricity-generating power plants convert hydrothermal fluids to electricity, depending on the state of the fluid and its temperature, in three ways – dry steam, flash steam, or binary cycle. Dry steam systems extract steam out of fractures in the ground, harvesting hot water and steam that can drive turbines on electricity generators.”
No matter how good all of this might sound, a number of advantages and disadvantages come into play when considering the development of geothermal energy plants. I have provided the following ‘advantages/disadvantages’ compilation, using information from energyinformative, TriplePundit, and ConserveEnergyFuture. There are plenty of pro/con lists to choose from, but I chose these.
→ Also recommended: Geothermal Energy: What It is & How It Works
→ Also recommended: Geothermal Energy Facts
Geothermal Energy Advantages
- Environmentally friendly – There are a few polluting aspects to harnessing geothermal energy, and the carbon footprint of a geothermal power plant is seen as minimal. An average geothermal power plant releases the equivalent of 122 kg CO2 for every megawatt-hour (MWh) of electricity it generates – one-eighth of the CO2 emissions associated with typical coal power plants.
- A renewable resource – Geothermal reservoirs are naturally replenished. According to some scientists, the energy in our geothermal reservoirs will last billions of years. While fossil fuels have an expiry date, renewable sources like geothermal energy is not going to expire anytime soon.
- Potential capacity – Estimates for the potential of geothermal power plants vary between 0.035 to 2 TW.
- A stable resource – The power output of a geothermal plant can be accurately predicted. Not subject to the same low-energy fluctuations as with solar or wind.
- Great for Heating/Cooling – There is significant growth in the number of homeowners utilizing geothermal heating/cooling over the last couple of years.
- No fuel required – After installation, no mining or transportation activity is necessary.
- Small land footprint – Smallest land footprint of any major power source.
- Stable resource – Can provide base load or peak power.
- Economic factors – Cost-competitive in some areas.
- Accessibility – Some level of geothermal energy available most places.
- Renewable – Geothermal energy is extracted from earth’s core and will be available as long as earth exists. It is therefore renewable and can be used for roughly another 4-5 billion years.
- Abundant Supply – With geothermal energy, there are no shortages or other sorts of problems which sometimes occur with other types of power.
- Significant Savings for Home Owners – There has been a tremendous increase in the number of homeowners who want to utilize geothermal energy for heating and cooling purposes. The result is that less energy is used for heating homes and offices which results in significant savings for home owners. After the initial expense, a 30-60% savings on heating and 25-50% savings on cooling can cover that cost within few years.
Geothermal Energy Disadvantages
- Potential emissions – Greenhouse gas below Earth’s surface can potentially migrate to the surface and into the atmosphere. Such emissions tend to be higher near geothermal power plants, which are associated with sulfur dioxide and silica emissions. Also, and the reservoirs can contain traces of toxic heavy metals including mercury, arsenic and boron.
- Surface Instability – Construction of geothermal power plants can affect the stability of land. In January 1997, the construction of a geothermal power plant in Switzerland triggered an earthquake with a magnitude of 3.4 on the Richter scale.
- High cost for electricity – Total costs usually end up somewhere between $2 – 7 million for a 1 MW geothermal power plant.
- High up-front costs for heating and cooling systems – While there is a predictable ROI, it will not happen quickly.For an average sized home, installation of geothermal heat pumps costs between $10,000 – $20,000 which can pay off itself in another 5-10 years down the line
- Location Specific – Good geothermal reservoirs are hard to come by. Iceland and Philippines meet nearly one-third of their electricity demand with geothermal energy. Prime sites are often far from population centers.
- Distribution costs – If geothermal energy is transported long distances, cost can become prohibitive.
- Sustainability questions – Some studies show that reservoirs can be depleted if the fluid is removed faster than replaced. This is not an issue for residential geothermal heating and cooling, where geothermal energy is being used differently than in geothermal power plants.
- Cost of Powering the Pump – Geothermal heat pumps need a power source.
- May Run Out of Steam: You have to be incredibly careful when you are trying to check everything that is related to geothermal energy. Mind must be taken to watch the heat and not to abuse it, because if the heat is not taken care of properly, it can cause a meltdown or other issues where the energy is not properly distributed or used.
Whether geothermal energy is going to be used for heating a house or generating electricity at a power plant, there is much to be looked at and considered. Although the footprint for this form of energy is considerably smaller than one than that of fossil fuels, it still has possible negative impacts. Then there is the issue of cost. Geothermal power plants are expensive to create and not always that easy to find. And the initial cost for buildings or houses using a geothermal heating and cooling system is expensive and without a fast payback.
Coming next, I will provide more details about geothermal energy systems and how they work.