Collection · COL-07

Power and Energy

Waves, solar mountains, wind turbines on airships, offshore rigs, footsteps, reactor pools, a car built to waste less fuel, a 582-ton fusion magnet, plasma squeezed by its own current, the world's largest hydropower dam, solar panels that float and an icebreaker driven by two reactors.

15 case files · 30 quiz questions · Tech, Locations, Science, Cars, Nature, Space

15 case files in this collection

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Free PDF: every quick fact with its ID, the write-ups, sources and a quiz with an answer key.

What Is in Power and Energy?

15 case files on where power comes from, and how to use less of it. Panthalassa's Ocean-3 nodes are 85 m steel floating data centers that make their own power from waves and send AI results to shore by satellite. DD-022 JR East's power-generating floor at Tokyo Station turns passengers' footsteps into electricity using piezoelectric discs, about 600 per square meter. DD-014

The Case Files, in Order

  1. 01
    DID YOU
    KNOW?    Ocean-3DD-022

    DD-022Tech

    Ocean-3

    This giant steel ball is an AI data center powered by waves.

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  2. 02
    DID YOU
    KNOW?    Guizhou SolarDD-032

    DD-032Tech+ Locations

    Guizhou Solar

    In Guizhou, solar panels cover whole mountains.

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  3. 03
    DID YOU
    KNOW?    Offshore OilDD-033

    DD-033Tech

    Offshore Oil

    Some oil rigs stand on legs, others float.

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  4. 04
    DID YOU
    KNOW?    Data CentersDD-029

    DD-029Tech

    Data Centers

    The internet lives in warehouses full of humming servers.

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  5. 05
    DID YOU
    KNOW?    Footstep PowerDD-014

    DD-014Tech

    Footstep Power

    These floor tiles turn footsteps into electricity.

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  6. 06
    DID YOU
    KNOW?    Cherenkov GlowDD-020

    DD-020Science+ Tech

    Cherenkov Glow

    This blue glow is particles outrunning light in water.

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  7. 07
    DID YOU
    KNOW?    Probe IVDD-002

    DD-002Tech+ Cars

    Probe IV

    Ford's 1983 Probe IV concept car (built with Ghia) had a drag coefficient of about 0.15.

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  8. 08
    DID YOU
    KNOW?    Airborne Wind TurbinesDD-050

    DD-050Tech+ Science

    Airborne Wind Turbines

    China flew a wind turbine 2,000 meters up.

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  9. 09
    DID YOU
    KNOW?    Hefei FusionDD-738

    DD-738Tech+ Science

    Hefei Fusion

    A 582-ton superconducting magnet built for fusion research.

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  10. 10
    DID YOU
    KNOW?    (Z) Pinch MeDD-741

    DD-741Science+ Tech

    (Z) Pinch Me

    A plasma squeezed by its own current.

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  11. 11
    DID YOU
    KNOW?    Three GorgesDD-643

    DD-643Locations+ Tech

    Three Gorges

    The world's biggest power plant.

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  12. 12
    DID YOU
    KNOW?    FloatovoltaicsDD-608

    DD-608Tech+ Nature

    Floatovoltaics

    Solar farms that float.

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  13. 13
    DID YOU
    KNOW?    Uranium UralDD-579

    DD-579Tech

    Uranium Ural

    Two reactors, three propellers.

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  14. 14
    DID YOU
    KNOW?    EnergizerDD-236

    DD-236Tech+ Science

    Energizer

    Lithium-ion batteries start with lithium, cobalt, nickel and graphite.

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  15. 15
    DID YOU
    KNOW?    Type IDD-263

    DD-263Science+ Space

    Type I

    The Kardashev scale ranks civilizations by the energy they use.

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Collection Quiz

All quizzes →

30 questions from all 15 case files in Power and Energy. Test Your Knowledge: answers are revealed instantly.

  1. Roughly how tall is a Panthalassa Ocean-3 node?

    1. About 8.5 m
    2. About 25 m
    3. About 85 m
    4. About 850 m
    Show the answer

    Answer: C. About 85 m Now You Know: Each node is about 85 m of plate steel, close to the height of Big Ben. Source: DD-022 · Ocean-3 · Write-up · Exhibit B (About 85 meters of steel) · Can floating data centres meet AI's huge energy demand? (New Scientist); Building inference data centers on the high seas (Latitude Media, Catalyst podcast with CEO Garth Sheldon-Coulson); Silicon Valley bets $200M on AI data centers floating in the ocean (Ars Technica, May 5, 2026)

  2. How does Ocean-3 make its electricity?

    1. Solar panels on the sphere
    2. Seawater forced up its tube by the waves spins turbines
    3. A small diesel generator
    4. A power cable from shore
    Show the answer

    Answer: B. Seawater forced up its tube by the waves spins turbines Now You Know: As waves lift and drop the node, seawater is driven up the tube into the sphere, where it spins turbines. Source: DD-022 · Ocean-3 · Write-up · Exhibit C (How the waves make power) · Can floating data centres meet AI's huge energy demand? (New Scientist); Silicon Valley bets $200M on AI data centers floating in the ocean (Ars Technica, May 5, 2026); Panthalassa unveils wave-powered floating data center platform (DCD, May 1, 2026)

  3. Which Chinese province is famous for solar panels blanketing whole mountains?

    1. Hainan
    2. Guizhou
    3. Heilongjiang
    4. Jiangsu
    Show the answer

    Answer: B. Guizhou Now You Know: Guizhou in southwest China has built large solar bases on its karst hills. Source: DD-032 · Guizhou Solar · Write-up · Exhibit A (Karst country) · Better forestation aids Guizhou environment (China Daily, Nov. 2020); Bare no more, Guizhou province's hills go green (China Daily, June 2023)

  4. What is 'rocky desertification'?

    1. Sand dunes spreading
    2. Erosion stripping soil to bare rock
    3. Rocks falling from cliffs
    4. Desert heat cracking rocks
    Show the answer

    Answer: B. Erosion stripping soil to bare rock Now You Know: On fragile karst, soil erodes away, leaving barren limestone. Source: DD-032 · Guizhou Solar · Write-up · Exhibit A (Karst country) · Better forestation aids Guizhou environment (China Daily, Nov. 2020); Bare no more, Guizhou province's hills go green (China Daily, June 2023)

  5. What kind of rig lowers its legs to the seafloor and lifts its hull out of the water?

    1. Drillship
    2. Jack-up
    3. Semi-submersible
    4. Tension-leg platform
    Show the answer

    Answer: B. Jack-up Now You Know: A jack-up stands on legs in shallow water, up to about 450 ft. Source: DD-033 · Offshore Oil · Write-up · Exhibit C (Jack-ups: rigs on legs) · Types of MODUs (U.S. Coast Guard OCS National Center of Expertise); Selected list of specialized words and their definitions (BSEE glossary); Subsea Drilling, Well Operations and Completions (National Petroleum Council paper 2-11, via DOE)

  6. What keeps a conventional fixed platform in place?

    1. Anchors
    2. Thrusters
    3. Steel piles driven into the seabed
    4. Its own weight on sand
    Show the answer

    Answer: C. Steel piles driven into the seabed Now You Know: Its steel jacket is secured into the seabed with piles. Source: DD-033 · Offshore Oil · Write-up · Exhibit B (Fixed platforms) · Types of Fixed OCS Facilities (U.S. Coast Guard OCS National Center of Expertise)

  7. Roughly what share of the world's electricity did data centers use in 2024?

    1. 0.1%
    2. 1.5%
    3. 10%
    4. 25%
    Show the answer

    Answer: B. 1.5% Now You Know: The IEA estimates about 415 TWh, roughly 1.5% of global electricity. Source: DD-029 · Data Centers · Write-up · Exhibit B (1.5% of the world's electricity) · Energy and AI (IEA, 2025, full report PDF); Energy and AI: Executive summary (IEA)

  8. Which country used the most data-center electricity in 2024?

    1. China
    2. India
    3. United States
    4. Germany
    Show the answer

    Answer: C. United States Now You Know: The U.S. accounted for about 45%, ahead of China (25%) and Europe (15%). Source: DD-029 · Data Centers · Write-up · Exhibit B (1.5% of the world's electricity) · Energy and AI (IEA, 2025, full report PDF); Energy and AI: Executive summary (IEA)

  9. Which Japanese station tested a 'power-generating floor' at its ticket gates?

    1. Tokyo Station
    2. Osaka Station
    3. Sapporo Station
    4. Kyoto Station
    Show the answer

    Answer: A. Tokyo Station Now You Know: JR East tested it at Tokyo Station's Yaesu North gates. Source: DD-014 · Footstep Power · Write-up · Exhibit A (Tokyo Station's power floor) · Demonstration Experiment of the 'Power-Generating Floor' at Tokyo Station (JR East press release, Jan 11, 2008); Known and unknown phenomena… in the power harvesting mat (Takefuji, NOLTA 2008); Power Generating Floor Tested at JR Tokyo Train Station (Japan for Sustainability, May 2008)

  10. What turns footsteps into electricity in JR East's floor?

    1. Solar cells
    2. Piezoelectric discs
    3. Tiny wind turbines
    4. Thermoelectric plates
    Show the answer

    Answer: B. Piezoelectric discs Now You Know: Piezoelectric elements (35 mm discs, about 600 per m²) convert pressure and vibration into voltage. Source: DD-014 · Footstep Power · Write-up · Exhibit B (Piezo discs underfoot) · Power Generating Floor Tested at JR Tokyo Train Station (Japan for Sustainability, May 2008); Demonstration Experiment of the 'Power-Generating Floor' at Tokyo Station (JR East press release, Jan 11, 2008)

  11. In water, light travels at roughly what fraction of its speed in a vacuum?

    1. About 25%
    2. About 75%
    3. About 99.9%
    4. About 150%
    Show the answer

    Answer: B. About 75% Now You Know: Light slows to about 75% of its vacuum speed in water, so fast particles can outrun it there. Source: DD-020 · Cherenkov Glow · Write-up · Exhibit B (Water slows light to 75%) · Cherenkov Radiation, Explained (U.S. Department of Energy, Office of Nuclear Energy, 2023); What is Cherenkov Radiation? (IAEA); What is Cerenkov Radiation? (Hong Kong Observatory)

  12. Cherenkov radiation is often compared to which everyday effect?

    1. A rainbow
    2. An echo
    3. A sonic boom
    4. Static electricity
    Show the answer

    Answer: C. A sonic boom Now You Know: It's a 'shockwave' of light, the optical version of a sonic boom. Source: DD-020 · Cherenkov Glow · Write-up · Exhibit D (A sonic boom for light) · Cherenkov Radiation, Explained (U.S. Department of Energy, Office of Nuclear Energy, 2023); What is Cherenkov Radiation? (IAEA); Cherenkov radiation (Wikipedia)

  13. What was the Probe IV concept car's drag coefficient?

    1. About 0.60
    2. About 0.45
    3. About 0.30
    4. About 0.15
    Show the answer

    Answer: D. About 0.15 Now You Know: The Probe IV's drag coefficient was about 0.15. Source: DD-002 · Probe IV · Write-up · Exhibit B (Cd ≈ 0.15)

  14. In what year did Ford build the Probe IV concept?

    1. 1983
    2. 1963
    3. 1999
    4. 2008
    Show the answer

    Answer: A. 1983 Now You Know: The Probe IV was a 1983 Ford concept car. Source: DD-002 · Probe IV · Write-up · Exhibit A (1983 Ford concept)

  15. What lifts China's S2000 airborne wind turbine?

    1. Rotors like a helicopter
    2. A helium-filled aerostat
    3. A kite
    4. A rocket
    Show the answer

    Answer: B. A helium-filled aerostat Now You Know: It's a buoyant, ducted airship tethered to the ground. Source: DD-050 · Airborne Wind Turbines · Write-up · Exhibit C (An airship that's a turbine) · Airborne wind power system generates 385 kWh at 2,000 meters in maiden flight: developer (Global Times, Jan. 2026); World's first megawatt-level airborne 'windmill' feeds power to grid (Interesting Engineering)

  16. How high did the S2000 fly on its January 2026 test?

    1. 200 m
    2. 2,000 m
    3. 20,000 m
    4. 50 m
    Show the answer

    Answer: B. 2,000 m Now You Know: It took about 30 minutes to reach 2,000 m. Source: DD-050 · Airborne Wind Turbines · Write-up · Exhibit B (S2000 on the grid) · World's first urban-use MW-class high-altitude wind turbine completes test flight (Global Times, Jan. 2026); Airborne wind power system generates 385 kWh at 2,000 meters in maiden flight: developer (Global Times, Jan. 2026); World's first megawatt-level airborne 'windmill' feeds power to grid (Interesting Engineering)

  17. How much does the Hefei TF magnet weigh?

    1. About 58 t
    2. 582.4 t
    3. 5,824 t
    4. 58,240 t
    Show the answer

    Answer: B. 582.4 t Now You Know: 582.4 t. Source: DD-738 · Hefei Fusion · Write-up · Exhibit B (The numbers) · ASIPP (Chinese): 国际最大的聚变堆超导磁体研制成功 (June 27, 2026); China News Service via CAS: 全球尺寸最大聚变堆超导磁体在合肥下线

  18. What is its operating current?

    1. 98 A
    2. 980 A
    3. 98 kA
    4. 98 MA
    Show the answer

    Answer: C. 98 kA Now You Know: It operates at 98 kA. Source: DD-738 · Hefei Fusion · Write-up · Exhibit B (The numbers) · ASIPP (Chinese): 国际最大的聚变堆超导磁体研制成功 (June 27, 2026); China News Service via CAS: 全球尺寸最大聚变堆超导磁体在合肥下线

  19. What current does Sandia's Z typically use?

    1. About 26 million amps
    2. About 26 amps
    3. About 2,600 amps
    4. About 26 billion amps
    Show the answer

    Answer: A. About 26 million amps Now You Know: Z shots run at about 26 MA. Source: DD-741 · (Z) Pinch Me · Write-up · Exhibit C (Typical shots) · Sandia National Laboratories: About Z

  20. How long is a Z pulse?

    1. About 100 nanoseconds
    2. About 1 second
    3. About 1 minute
    4. About 1 hour
    Show the answer

    Answer: A. About 100 nanoseconds Now You Know: Energy is discharged in about a 100 ns pulse. Source: DD-741 · (Z) Pinch Me · Write-up · Exhibit B (The Z machine) · Sinars et al. (2020), Review of pulsed power-driven high energy density physics research on Z at Sandia, Physics of Plasmas

  21. What is Three Gorges' installed capacity?

    1. 22,500 MW
    2. 2,250 MW
    3. 225 MW
    4. 225,000 MW
    Show the answer

    Answer: A. 22,500 MW Now You Know: 32 x 700 MW plus 2 x 50 MW. Source: DD-643 · Three Gorges · Write-up · Exhibit A (Biggest by capacity) · Guinness World Records: Highest capacity hydroelectric power station; Engineering (2016): Key technologies of the hydraulic structures of the Three Gorges Project

  22. What is the dam's maximum height?

    1. 181 m
    2. 81 m
    3. 281 m
    4. 18 m
    Show the answer

    Answer: A. 181 m Now You Know: Its crest is at 185 m above sea level. Source: DD-643 · Three Gorges · Write-up · Exhibit B (How tall) · Engineering (2016): Key technologies of the hydraulic structures of the Three Gorges Project

  23. Where was the first floating solar system built?

    1. Aichi, Japan
    2. Nevada, USA
    3. Bavaria, Germany
    4. Gujarat, India
    Show the answer

    Answer: A. Aichi, Japan Now You Know: In 2007. Source: DD-608 · Floatovoltaics · Write-up · Exhibit A (On the water) · World Bank Group, ESMAP and SERIS (2019), Where Sun Meets Water: Floating Solar Market Report; Wikipedia: Floating solar

  24. Which is NOT a way floating solar platforms are anchored?

    1. Helium balloons
    2. To the bank
    3. To the bottom
    4. To piles
    Show the answer

    Answer: A. Helium balloons Now You Know: Per the World Bank report. Source: DD-608 · Floatovoltaics · Write-up · Exhibit B (First in Japan) · World Bank Group, ESMAP and SERIS (2019), Where Sun Meets Water: Floating Solar Market Report; Wikipedia: Floating solar

  25. How many nuclear reactors does Ural have?

    1. Two
    2. One
    3. Four
    4. Six
    Show the answer

    Answer: A. Two Now You Know: Two RITM-200 reactors. Source: DD-579 · Uranium Ural · Write-up · Exhibit C (Reactors to propellers) · Wikipedia: Ural (icebreaker); Wikipedia: Project 22220 icebreaker

  26. How many propellers does Ural have?

    1. Three
    2. One
    3. Two
    4. Four
    Show the answer

    Answer: A. Three Now You Know: Each is driven by a 20 MW electric motor. Source: DD-579 · Uranium Ural · Write-up · Exhibit C (Reactors to propellers) · Wikipedia: Ural (icebreaker); Wikipedia: Project 22220 icebreaker

  27. Which metal gives these batteries their name?

    1. Lithium
    2. Lead
    3. Zinc
    4. Iron
    Show the answer

    Answer: A. Lithium Now You Know: Lithium-ion. Source: DD-236 · Energizer · Write-up · Exhibit A (Raw materials) · Wikipedia: Lithium-ion battery

  28. What is the anode usually made of?

    1. Graphite
    2. Copper
    3. Silicon dioxide
    4. Gold
    Show the answer

    Answer: A. Graphite Now You Know: Carbon. Source: DD-236 · Energizer · Write-up · Exhibit B (Electrodes) · Wikipedia: Lithium-ion battery

  29. Who proposed the scale?

    1. Nikolai Kardashev
    2. Carl Sagan
    3. Enrico Fermi
    4. Frank Drake
    Show the answer

    Answer: A. Nikolai Kardashev Now You Know: In 1964. Source: DD-263 · Type I · Write-up · Exhibit A (1964) · Wikipedia: Kardashev scale

  30. What does it measure?

    1. Energy use
    2. Population
    3. Intelligence
    4. Age
    Show the answer

    Answer: A. Energy use Now You Know: Of civilizations. Source: DD-263 · Type I · Write-up · Exhibit B (Type I) · Wikipedia: Kardashev scale