Introduction to Energy — course slides
A three-day course for the I-BE³ bachelor’s degree of MINES Paris — PSL, on the Sophia Antipolis campus. What energy is and how we measure it, where it comes from and where it goes, and what a low-carbon transition actually demands.
By Robin Girard, MINES Paris — PSL, Centre PERSEE.
Slides from the 2026 edition, in English. Each deck is available as a PDF to read and as the original PowerPoint file to edit.
1. Introduction
What energy is — not a substance you own but a capacity to modify your environment — and what it has already done to us: fire and the human brain, coal and the first labour laws, Buckminster Fuller’s energy slaves. Then the three questions the rest of the course answers. What does energy cost, and who pays? Has a transition from one source to another ever been completed — the answer is no, sources have only ever stacked on top of each other. And which of the Kaya levers actually has the power to cut emissions: decarbonising supply, electrifying to gain efficiency, or sufficiency.
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2. History of Energy
How the idea of energy was built, from labour to work. Moving a 70-tonne statue with 172 haulers in Middle Egypt, Roman cranes, the Hierapolis sawmill and its crank; then Bernoulli in 1738, measuring what a man can actually lift in a second and daring to write that the latent force of a cubic foot of coal could replace it. Then the century that connected everything to everything — heat to motion, motion to heat, chemistry to electricity, electricity to magnetism — and Joule, an English brewer who set out to replace his coal engine with an electric motor, found it 25 times too expensive, and ended up with the conservation of energy. Ends with the units: the joule, the kilowatt-hour, the tonne of oil equivalent, and the difference between lower and higher heating value.
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3. Energy Efficiency and Thermodynamics
Why efficiency is a slippery word. A heat pump exceeds 100 %, a solar panel sits at 20 % and neither number means what it looks like. The Carnot ceiling explains why electricity from gas will never match electricity from a waterfall, and it is a bound from physics, not a gap in engineering. Then the rebound effect (the 2 CV of 1950 used 4.5 l/100 km; the C3 of 2018 uses 5), the three blind spots of final energy, and exergy — the ruler that does not move, which says that the 5.1 % of a joule you actually need to heat a room is bought by destroying a 1 900 °C flame.
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4. World Energy Consumption
Where the joules actually go. The world energy Sankey, then the three big consumers taken one by one: the materials (steel and plastics alone are 70 % of the industrial energy bill, and most industrial heat is below 200 °C), passenger transport in energy per passenger-kilometre, and freight in energy per tonne-kilometre — where the ranking surprises everyone, and where the ratio of payload to empty mass explains most of it. Then the world coal, gas and oil flow maps, because a third of freight tonnage is fossil fuel being carried to be burnt. Ends on sufficiency — lowering the thermostat by 1 °C saves more, in relative terms, in the badly insulated home — and on digital consumption, including what an AI query really costs.
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5. The Future Electric System
The longest deck, and the technical heart of the course. Where electricity stands today (a minority of final energy, a majority of the emissions), and the two levers: decarbonise the kilowatt-hour, then electrify the uses. The physics first — the solar constant, Betz’s limit for wind — then the question that matters: is a PV kilowatt-hour worth a nuclear one? Balancing the system across every time scale, from the 30 seconds of primary reserve to the fifteen-year investment horizon, and the flexibility that answers each of them: demand-side management, storage, sector coupling to hydrogen, methane and heat. Then the money: capacity factors, the discount rate and why it decides everything, LCOE for nuclear and for renewables, and how to read a generation cost in a newspaper article. Ends with the players, the markets and the balancing mechanism.
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7. Industrial Decarbonisation
Industry is 9.4 Gt of direct CO₂, and five products carry most of it: cement, steel, olefins, ammonia, aluminium. For each one, where the carbon actually comes from — half of cement’s emissions are the limestone itself, not the fuel — and what can be done about it: bioenergy, low-carbon electricity, decarbonised heat, capture, efficiency and sufficiency, changing the process, recycling. High-temperature heat storage as the technology to watch. Then hydrogen, honestly: today it is a problem (830 MtCO₂, made from gas and coal) before it can be a solution, and replacing the world’s coke in steelmaking would take 4 000 TWh of electricity. Ends on plastics and the routes to low-carbon monomers.
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8. Buildings and Transport
The two sectors where direct electrification does the work, and where its limits are. Heating: temperature sensitivity, what the RTE scenarios expect, and why electrifying it is not simply a matter of swapping the boiler. Transport: the electric vehicle is not one gain but two multiplied together — an efficiency gain of 90 % against 25-40 %, and a carbon gain of 339 gCO₂/kWh down to 10-15 — which is why the cascade from 20 to 60 to 180 kWh, drawn here for battery, hydrogen and synthetic fuel, settles the argument. Then the objections taken seriously: the life-cycle assessment of batteries, the materials and the mines, shipping and aviation (whose climate impact is three times its CO₂). Ends where the course must end — the binding constraint on the transition is political, not technical.
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All the decks sit in a single folder if you would rather browse it: all the slides, on the MINES Paris cloud.
The code behind the figures is being opened one family at a time: see Figures and code.
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The text, the layout and the figures I made myself are under CC BY 4.0, and the code that produces those figures is under the MIT licence. Take them, translate them, cut them up, use them in your own teaching — just say where they come from.
One reservation, and it matters. These slides also carry third-party material: figures from other authors, scenario charts from the IEA and from the French SNBC, press photographs, screenshots of scientific papers. Those are not mine to license. They appear here under the short-quotation exception for teaching, each with its source on the slide. If you want to reuse one of them, go to its source and ask its author — not me.