…
It takes
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- Energy
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- Joules
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- Calories
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Key takeaway
Figures in this anecdote assume an average dam (135 m, 87%).
Free · no sign-up · sourced figures
Turn any activity into litres of water
Type any everyday action: AquaLitre works out the energy it uses and tells you how many litres of water must fall through a dam to produce it.
E = P × t: the result updates live.
1 Wh = 3,600 J · 1 kcal ≈ 1.163 Wh · 1 toe = 11,630 kWh
Equivalents
The same energy, other ways
How much uranium, wind, sunshine or leg power it would take to produce exactly the same amount of electricity.
Uranium
PWR nuclear reactor
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of natural uranium dug out of the mine
- Enriched UO₂ fuel
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- Uranium-235 fissioned
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Wind turbine
Onshore, 3 MW
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of the blades at average output (23% load factor)
- Time, average output
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- Time, full power
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Sunshine
400 Wp solar panel
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of full sun on a single panel
- Area for 1 h of sun
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- Panels for one day
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Cyclist
Pedal generator, 100 W
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of steady pedalling at 100 W
- Food calories
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- Butter croissants
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Depending on the dam
The higher the water falls, the less of it you need.
To picture it
The same energy, on a human scale.
French grid average: 25 g CO₂/kWh
Comparison
Eight ways to produce the same energy
Material used, water, CO₂ and dispatchability, calculated for:
| Source | For this use | Material used | Water | CO₂ emitted | Dispatchable |
|---|
Orders of magnitude
The density shock
× 1.4 million
Uranium vs water
1 g of enriched uranium makes as much electricity as 1,428 tonnes of water falling 135 m.
× 50
Wind vs water
Air is 800 times less dense than water: for 1 kWh, a wind turbine sweeps about 160 t of air, while a dam runs 3.1 t of water through its turbines.
93 h
Petrol vs legs
One litre of petrol holds 9.3 kWh: 93 hours of pedalling at 100 W, or about 145 butter croissants.
÷ 180
Low-carbon vs coal
A kWh from hydro or nuclear emits 4–6 g of CO₂, against 1,060 g from coal.
Catalogue
Everyday examples
Calculated, sourced situations: click one to convert it.
History
Latest questions to the AI
Every Gemini answer is saved with its calculation and sources.
My day
My day in litres
Add up your day: AquaLitre totals the energy and the dam water needed to power everything you do.
Energy duel
Which one uses more?
Pick two uses: AquaLitre measures the gap between them in dam water, uranium, wind and sunshine.
Quiz
Guess the litres
Can you guess how much water, how much uranium or how many turbine turns lie behind these situations?
Method & sources
How AquaLitre calculates
Every conversion relies on simple laws of physics and on public figures from reference bodies. Here are the formulas and assumptions — no black box.
1. Water from dams
The potential energy of a mass of water m = ρ · V falling through a net head H is turned into electricity with an overall efficiency η (turbine, generator, transformer).
E = ρ · g · V · H · η ⇒ V (L) = E (Wh) × 3,600 / (9.81 × H × η)
| Reference dam | Head H | Efficiency η | Water per Wh |
|---|---|---|---|
| French average (Francis, Kaplan, Pelton) | 135 m | 87% | 3.12 L |
| Run-of-river (Rhône, Rhine — Kaplan) | 15 m | 88% | 27.8 L |
| Large reservoir (Serre-Ponçon — Francis) | 120 m | 87% | 3.52 L |
| High head (Grand'Maison — Pelton) | 900 m | 89% | 0.46 L |
Sources: RTE (French grid operator), electricity report · EDF Hydro · Compagnie Nationale du Rhône
2. Uranium in pressurised water reactors
Completely fissioning one gram of uranium-235 releases about 82 GJ of heat (22,700 kWh). With a thermodynamic efficiency of about 33%, that gives nearly 7,500 kWh of electricity.
1 UO₂ pellet (7 g, ~4% enriched) ≈ 3,200 kWh · 1 kWh ≈ 20.8 mg of natural uranium mined
On the water side, a plant with cooling towers evaporates about 2.2 L per kWh and withdraws about 45 L from the river, most of which is returned.
Sources: CEA (French Alternative Energies and Atomic Energy Commission), fuel cycle · Orano · World Nuclear Association
3. Wind through turbines
A typical onshore turbine in the French fleet is rated at 3 MW with an average annual load factor of 23%, i.e. 690 kW on average. Its rotor turns at about 12 revolutions per minute.
1 rotor turn (5 s) ≈ 958 Wh on average · 3,571 Wh at full power
The mass of air flowing through the rotor follows from the kinetic energy recovered: m = E / (½ · v² · Cp), i.e. about 160 kg of air per Wh for a 10 m/s wind and a power coefficient Cp of 0.45.
Sources: RTE, wind generation · ADEME (French Agency for Ecological Transition)
4. Sunshine on solar panels
A standard monocrystalline panel measures 1.95 m² for 400 Wp (about 20.5% efficiency). In full sun (1,000 W/m²), it produces 400 Wh per hour.
Average yield in France ≈ 1,200 kWh/kWp/year ⇒ 1,315 Wh per day per panel
Sources: European Commission, PVGIS · RTE, solar generation
5. Legs, petrol and CO₂
A trained cyclist can sustain about 100 W on a pedal generator. With a muscle efficiency of 22%, 1 kWh of mechanical work costs nearly 3,900 food kcal — around fifteen butter croissants (≈ 250 kcal each). One litre of petrol holds about 9.3 kWh.
| Source | g CO₂e per kWh |
|---|---|
| Nuclear · hydro | 4 · 6 |
| Wind · solar | 14 · 32 |
| Gas (combined cycle) · fuel oil · coal | 418 · 730 · 1,060 |
| French power mix · global mix | ~25 · ~475 |
For human power, the CO₂ comes from food: about 2.3 t CO₂e per French person per year, which works out at roughly 10 kg CO₂e per kWh produced by leg power.
Sources: ADEME, Base Empreinte · IEA · ANSES, Ciqual food composition table · Carbone 4, “Faire sa part ?”
6. Limitations
Results are orders of magnitude: they depend on average assumptions (typical dam, load factor, efficiency). For thermal uses (petrol car, plane), the energy counted is that of the fuel burnt.
AI answers are estimates: they show their assumptions and sources so you can check them. A question that has already been asked is served from the history, with no new call.