Geothermal and Oil Shales and Sands

The Great Energy DebateBy: Elizabeth Hart and Erica Butts

What is geothermal energy?• Energy obtained by tapping underground reservoirs of heat,

usually near volcanoes or other hot spots on the surface of the Earth. Geo – Earth Thermal – Heat

Examples of how Geothermal Energy is used

• Direct geothermal energy: In areas where hot springs or geothermal reservoirs are near the Earth’s surface, hot water can be piped in directly to heat homes or office buildings. Geothermal water is pumped through a heat exchanger, which transfers the heat from the water into the building’s heating system. The used water is injected back down a well into the reservoir to be reheated and used again.

• Geothermal heat pump: A few feet under the ground, the soil or water remain a constant 50 to 60 degrees Fahrenheit year-round. Just that little bit of warmth can be used to heat or cool homes and offices. Fluid circulates through a series of pipes (called a loop) under the ground or beneath the water of a pond or lake and into a building. An electric compressor and heat exchanger pull the heat from the pipes and send it via a duct system throughout the building. In the summer the process is reversed. The pipes draw heat away from the house and carry it to the ground or water outside, where it is absorbed.

• Geothermal power plant. Hot water and steam from deep underground can be piped up through underground wells and used to generate electricity in a power plant. Three different types of geothermal power plants exists:

1. Dry steam plants: Hot steam is piped directly from geothermal reservoirs into generators in the power plant. The steam spins turbines, which generate electricity.

2. Binary cycle plants: Moderately hot geothermal water is passed through a heat exchanger, where its heat is transferred to a liquid (such as isobutene) that boils at a lower temperature than water. When that fluid is heated it turns to steam, which spins the turbines.

3. Flash steam plants: Water that’s between 300 and 700 degrees Fahrenheit is brought up through a well. Some of the water turns to steam, which drives the turbines. When the steam cools it condenses back into water and is returned to the ground.

Advantages of using Geothermal Energy

• It is renewable. Since geothermal energy comes from the heat of the earth, it is considered to be renewable resource. This means that you can use and reuse it over and over again. Itcan be considered as a lifetime energy source since the earth itself is the one that gives off this heat. You can be assured that there will be a continuous source of energy.

• It is clean. Geothermal energy is classified as one of the clean sources of energy because it does not burn fossil fuel in producing electricity. And since it does not burn fossil fuels, carbon dioxide in the air is greatly reduced.

• High heat source. The energy coming from beneath the earth is really powerful allowing geothermal plants to generate much electricity.

Disadvantages of using Geothermal Energy

• Hazardous gases and minerals- come up from underground along with the steam. One of the most common substances to be released is hydrogen sulfide, which is extremely difficult to dispose of safely. Other minerals that can be troublesome are arsenic, mercury, and ammonia. In addition to geothermal energy extraction releasing hazardous gases and minerals, it can also cause earthquakes.

• Huge startup costs- when trying to build a geothermal plant, there is a great deal of capitalization needed especially at the start. Drilling and testing whether a certain area is suitable for a geothermal plant costs a lot of money.

• One of the biggest disadvantages of geothermal energy is the low number of suitable locations for a power plant. An ideal location has suitable hot rocks at a depth that allows for easy drilling. The type of rock above the hot rocks must also be easy enough to drill through. After finding a suitable location, there is another drawback.

Historical Problems

• The only huge issues that have been presented due to geothermal energy is the areas available to create the energy plants. This is because geothermal energy is from underground reservoirs of heat. For example, most geothermal energy plants in the United States are located in the West. The largest geothermal development in the world is The Geysers north of San Francisco, California.

Recent energy problems

Hawaii residents raise serious concerns about PGV, Geothermal Energy’s clean energy credentials

• Longstanding residents of area around PGV’s geothermal plant– now being expanded– were given a long overdue public hearing on geothermal energy recently at a special session of the Hawaii County Council in Pahoa.• Open venting of geothermal gases and liquids are overflowing with toxic chemicals and heavy metals, poor environmental monitoring, control and reporting, corporate lies, and very serious environmental health and safety concerns were addressed at the public hearing.• Hawaii is looking to further develop the geothermal energy resources as sources of clean, stable, long-lasting electrical power.

A possible way of solving this problem is first by notifying the residents in the area (which was done at the public hearing). Next, the PGV’s geothermal energy plant should work to 1. purify the energy being produced or 2. stop using this specific energy plant until the geothermal gases and liquids are pure again. The energy plant should continue to prove its legitimacy and care towards the issue and keep the residents of the area updated on the issue.

What is oil shale?• Oil shale is a type of sedimentary rock from which

oil can be extracted. Oil shale and sands can be found in oil shale deposits in oil-rich regions such as The Democratic Republic of Congo and Morocco.

Examples of how oil shale is used

• Oil shale is converted to shale oil through pyrolysis, hydrogenation and thermal dissolution, and then is used as fuel. Fuels such as shale oil are utilized in combustion like gasoline and other fossil fuels.

Advantages of oil shales

• Right now, production of oil shale is very high, and is very abundant.

• It is very efficient in terms of energy input and output.

• It makes a lot of money.

Disadvantages of oil shales

• Shale oil gives off sulfur, carbon dioxide, ethylene, carbon monoxide and hydrogen sulfide. These gases can be detrimental to human health.

• The property and cost of extracting oil shale and sands is very expensive.

• A lot of energy is used to extract the oil sands as well.

Historical Problems

• Many conflicts have taken place over oil shale in the 20th century, from forced labor mining in Manchuria, China, to embargoes in the 1970's by Middle Eastern countries. These conflicts were solved by President Nixon, and his effort to create more domestic energy sources and more plants to synthesize liquid sources of energy.

Recent energy problems

• Shale oil use and the use of all fossil fuels has been an issue in America for the last few decades. The United States has been trying to utilize renewable resources that are cheap and efficient. From things like wind power, to hydroelectric-powered cars, our society has been advancing into the future with more environmentally friendly energy sources.

Citations• Diagrams- www.google.com • http://www.c2es.org/technology/factsheet/geothermal• http://www.energy-consumers-edge.com/pros_and_cons_of_geothermal

_energy.html• http://cleantechnica.com/2012/04/28/hawaii-residents-raise-serious-conc

erns-about-pgv-geothermal-energys-clean-energy-credentials/

• http://www.thinkglobalgreen.org/geothermal.html