How would you like to swim in waters heated by a volcano? That's what people in Iceland do all the time--even in winter. Volcanoes, hot springs, and similar sources of energy not only let Icelanders swim outdoors even when it's freezing cold, but they also heat more than 90 percent of Iceland's homes and provide more than a quarter of its electricity.
The U.S. doesn't have as many easy-to-tap hotspots as Iceland. But that doesn't mean there isn't plenty of geothermal energy deep below us. It just may take more effort--and ingenuity--to get at it. Now, engineers are testing a new technology that could unlock this energy--including at a dormant, or inactive, volcano in Oregon. The technology is called enhanced geothermal systems (EGS).
For EGS to work, engineers need to make a network of tiny cracks in the ground. As water rises through these cracks, it heats up. The tricky part is creating enough of these tiny cracks without disturbing people or the environment.
THE HEAT IS ON
Deep underground, Earth constantly generates heat. "The fundamental trick with geothermal energy is trying to get the heat out of the ground," says Stephen Hickman, a geophysicist at the United States Geological Survey.
Earth's crust consists of tectonic plates that slowly glide over molten rock beneath. "Plate tectonics are causing Earth's crust to pull apart like a piece of taffy in some places, and as you pull it apart it gets thinner and thinner," says Hickman. "That brings the hotter rock up closer to the surface." In places where plates are spreading apart--such as Iceland and parts of the western U.S.--the heat is fairly easy to reach.
In places where water naturally circulates through cracks in the hot rock, people can drill a well, pump the hot water to the surface, and use the heat to generate electricity or heat homes. But in many spots--such as Newberry Volcano in Oregon the hot rock is dry. "In those places we have hot rocks at a depth that have a lot of energy in them, but we have no easy way to get the energy out," says Hickman.
That's where EGS comes in. "In EGS we make the cracks and then put the water in there to pick up the heat," says groundwater hydrologist Susan Petty. She's the president of AltaRock Energy, the company attempting to tap Newberry Volcano for its heat energy. AltaRock Energy is just one of many companies testing this new technology.
ALL CRACKED UP
To create the tiny cracks, EGS uses hydroshearing (not to be confused with hydraulic fracturing, or fracking, which pumps high-pressure fluids containing chemicals into the ground to create large cracks to access oil and gas; see Science World, April 16-30, 2012).
During hydroshearing, workers pump water--without added chemicals--deep into the ground to trigger small earthquakes that usually can't be felt. Machines then pump water through the cracks, where it absorbs Earth's heat and carries it back up to the surface.
ENERGY OF THE FUTURE?
Most EGS projects are still in the testing stage, but the technology could have major benefits. Unlike fossil fuels like oil, gas, and coal, geothermal energy doesn't emit greenhouse gases such as carbon dioxide. And unlike wind and solar energy, which depend on weather and climate, geothermal energy is always available, everywhere.
"It is 24/7," says Petty. "We can drill a hole anyplace on the planet, and, if we go deep enough, we're going to find temperatures hot enough to make electricity or to use for home heating? You don't even need a volcano.
WATCH A VIDEO ONLINE www.scholastic.com /scienceworld
CORE QUESTION Why is it easier to produce geothermal energy in Iceland than in the U.S.?
Geothermal energy is normally harnessed from an underground supply of water heated by Earth's interior. A new technology that pumps water through cracks in dry, hot rocks could allow us to tap more of this energy. The hot water can then be used to generate electricity.
BRINGING UP THE HEAT
NATIONAL SCIENCE EDUCATION STANDARDS:
Grades 5-8: Risks and benefits
Grades 9-12: Science and technology in local, national, and global challenges
COMMON CORE STATE STANDARD:
LITERACY IN SCIENCE: 8. Distinguish among facts, reasoned judgment, and speculation in a text.
Understand what geothermal energy is and how a new technology uses tiny earthquakes to access heat energy deep underground.
* What is alternative energy? (energy that comes from a source other than fossil fuels like oil and gas)
* What are some types of alternative energy sources? (wind; solar; hydropower; geothermal; tidal)
* What is geothermal energy? (the heat energy from within Earth, used to heat homes or to produce electricity)
* what are some places where heat from within Earth reaches the surface? (volcanoes, hot springs, and geysers)
1. Go to www.scholastic.com/scienceworld and open the digital edition of Science World to page 18. Have students do the same in their magazines. Ask for a volunteer to read the headline and the bold print below it. Have students predict what the article is going to be about.
2. Ask students the before-reading questions. Discuss why scientists are looking into alternative energy sources. (Fossil fuels are nonrenewable and cause pollution.)
3. Have a different volunteer read each paragraph aloud.
(D) 4. Open four digital sticky notes and label them: Fossil Fuels, Wind, Hydropower, and Geothermal. For each type of energy, brainstorm a list of pros and cons. Consider cost, how easily the energy can be accessed, whether it is renewable, whether it causes pollution, what risks it involves, etc.
5. Ask students how they think geothermal energy compares with the other energy sources, why might a mix of many energy sources be necessary to supply electricity in the U.S.?
After reading the article, discuss the risks and the benefits of geothermal energy. Do students think it is worth it to try to build a system that creates cleaner energy if it risks setting off small earthquakes? Discuss how risks and benefits must be balanced when making any energy choice.
Assessments are tailored to different science disciplines and the Common Core State Standards. To download, go to www, scholastic.com/scienceworld and click on the orange Skills Sheets button.
PHYSICS/COMMON CORE: CRITICAL THINKING
FACT OR OPINION?
Use this work sheet to have students analyze statements related to the article and determine whether each is a fact or an opinion.
EARTH SCIENCE: DIAGRAM READING
STRUCTURE OF THE EARTH
Where does geothermal energy originate? Use this diagram-reading activity to learn how temperature increases with depth through Earth's layers.
BIOLOGY: READING COMPREHENSION
Read a short passage to learn about the surprising discovery of a new species of worm that lives in hot rocks at depths similar to those at which geothermal energy is accessed.
* VIDEO EXTRA: Watch a video about geothermal energy at: www.scholastic.com/scienceworld.
* This kid-friendly site has more information about geothermal and other alternative energy sources: http://wwweia.gov /kids/energy.cfm?page=geothermal_home-basics-k.cfm.
* Find activities related to geothermal energy here: http://www1.eere.energy.gov/education/pdfs /geothermal_energy.pdf.
DIGITAL ISSUE KEY:
(A) SHOW ALL PAGES
(C) MASK TOOL
(D) DIGITAL STICKY NOTES
(E) TEXT HIGHLIGHTER
(F) DRAWING TOOL
(I) VIDEO PLAYER
DIRECTIONS: Fill in the blanks in the following sentences.
1. More than -- percent of homes in Iceland get their heat from geothermal sources.
2. An inactive -- in Oregon is one test site for a new geothermal technology.
3. Enhanced geothermal systems rely on a network of small -- in the ground.
4. Pieces of Earth's crust called -- plates move on top of molten rock.
5. When no -- is present in the hot rocks beneath the surface, it is difficult to bring up Earth's heat energy.
6. The process of using water to make tiny cracks in the ground is called --.
7. One risk of enhanced geothermal systems is that creating them can trigger small --.
8. Use of geothermal energy does not release -- -- such as carbon dioxide.
9. Unlike clean energy sources that depend on the weather, such as wind and --, geothermal energy is available all the time.
10. When hot water is pumped up to the surface, the -- it releases turns turbines to generate electricity.
1. 90 2. volcano 3. cracks 4. tectonic 5. water 6. hydroshearing 7. earthquakes 8. greenhouse gases 9. solar 10. steam