¿Podemos aprovechas el poder de la lava? - Jean-Baptiste P. Koehl

0:07 While the weather in Iceland is often cold, wet, and windy,

0:12 a nearly endless supply of heat bubbles away below the surface.

0:17 In fact, almost every building in the country is heated by geothermal energy,

0:22 in a process with virtually no carbon emissions.

0:26 So how exactly does this renewable energy work?

0:30 Between the Earth’s core and its crust is a mixed

0:33 layer of solid and partially molten rock called the mantle.

0:38 Temperatures here range from 1,000 to 3,500 degrees Celsius.

0:44 Some of this heat comes from the radioactive decay of metals.

0:49 But much of it comes from Earth’s core, which has been radiating energy since

0:54 the planet formed over four billion years ago.

0:57 While the mantle moves slowly,

0:59 circulating roughly 40 kilometers below the Earth’s crust,

1:03 there are places where it surges closer to the surface.

1:07 Here, the magma forms pockets and veins in the ground,

1:11 heating underground rivers and pools to temperatures reaching 300 degrees.

1:17 Controlling heated water is at the heart of harnessing geothermal energy,

1:22 and there are two primary models for how to do it.

1:25 One is to build a geothermal power plant which uses these hot,

1:30 deep pools to produce electricity.

1:33 First, engineers drill a well several kilometers

1:36 into permeable rock like sandstone or basalt.

1:40 As the hot, highly pressurized groundwater flows into the well,

1:45 the rapid change in pressure and temperature produces huge amounts of steam.

1:49 This steam then turns the blades of a turbine to generate electricity.

1:55 Finally, the remaining cooled water and condensed steam are injected back

1:59 into the ground to create an open

2:02 loop that provides electricity without losing water.

2:06 However, we don't have to drill this deep

2:08 to take advantage of the planet's heat.

2:11 Thanks to solar radiation,

2:13 dirt just 1.5 meters deep can reach temperatures over 20 degrees Celsius.

2:19 Geothermal heat pumps pipe water or antifreeze liquid

2:23 through this layer of earth to siphon its energy.

2:26 These liquids are then pumped through local infrastructure,

2:30 dispersing their heat before moving back

2:32 through the ground to absorb more energy.

2:34 While external electricity is needed to operate the pumps,

2:38 the energy provided is far greater than the energy used,

2:42 meaning this process is also a sustainable loop.

2:46 In fact, geothermal heat pumps are both cheaper to operate

2:50 and at least two times more energy efficient than fossil fuel equivalents.

2:55 Whether geothermal energy is radiating just below our feet,

2:59 or heating water several kilometers deep,

3:01 the planet is constantly radiating heat.

3:04 Averaged across one year,

3:06 Earth gives off roughly three times more energy than humanity consumes.

3:12 So why does geothermal only account for 0.2% of humanity’s energy production?

3:18 The answer has to do with heat, location, and cost.

3:22 Since geothermal heat pumps rely on the consistent heat found in shallow earth,

3:28 they can be implemented almost anywhere.

3:31 But geothermal power plants require

3:33 tapping into high-temperature geothermal fields;

3:37 regions hotter than 180 degrees and typically several kilometres underground.

3:43 These high temperature zones are hard to find,

3:46 and drilling this deep for just one of the several

3:49 wells a plant will need can cost up to $20 million.

3:54 There are regions with shallower geothermal fields.

3:58 Iceland and Japan are near active volcanoes and tectonic plate boundaries,

4:02 where magma rises up through the crust.

4:05 But these same factors also make those regions prone to earthquakes,

4:09 which can also be triggered by intensive drilling.

4:13 Furthermore, while geothermal energy is clean and renewable,

4:17 it’s not entirely harmless.

4:19 Drilling can release vapors containing

4:22 pollutants like methane and hydrogen sulfide.

4:25 And drilling tools that use pressurized water can contaminate groundwater.

4:30 Fortunately, new technologies are emerging to meet these challenges.

4:34 Emission control systems can capture pollutants,

4:38 and electromagnetic monitoring can help detect seismic risks.

4:42 We're also uncovering entirely new sources of geothermal energy,

4:47 like pockets of magma in mid-ocean volcanoes.

4:51 So if we can safely and responsibly tap into the heat sustaining our planet,

4:56 we might be able to sustain humanity as well.