How the Lights Stay On

Chapter 14: The Trilemma

There is a question that has divided energy experts for fifty years, and it has an answer that most people who are not energy experts have never heard.

The question is this: what should we want from an electricity system?

The answer, on the surface, seems obvious. We want the lights to stay on. We want our bills to be affordable. We want the system to be clean — to not be wrecking the climate or poisoning the air.

The trouble is that no electricity system in the world delivers all three of these things equally well. Every country, every state, every utility, is making a trade-off. Sometimes the trade-offs are explicit, made by voters and regulators in public hearings. Sometimes they are implicit, baked into decisions made decades ago whose costs only become visible during a crisis.

This chapter is about the trade-off. It is about the framework that lets you understand why France’s grid is different from Germany’s grid is different from Texas’s grid is different from California’s grid. It is also about why understanding this framework will make you smarter than most adults about energy for the rest of your life.

The framework has a name. People who work in energy call it the trilemma.

Picture a triangle. Three corners. Three goals.

The first corner is reliable. The lights stay on. When you flip the switch, electricity is there. When a storm hits, the system recovers fast. There are no rolling blackouts during a heat wave. There are no surprises.

The second corner is affordable. The electricity bills are reasonable. Industry can compete on a global stage without being crippled by energy costs. Poor families can afford to heat their homes in winter. Schools and hospitals can run without breaking their budgets.

The third corner is clean. The system does not pump enormous amounts of carbon into the atmosphere. The air around power plants is breathable. Mining and waste impacts are managed responsibly. The lifecycle environmental damage is minimized.

Now here is the trilemma. You can have any two of these three. You cannot have all three.

If you optimize for reliable and affordable, you are mostly burning fossil fuels — particularly coal and natural gas. They are cheap, they are dispatchable, they are the easiest way to run a grid that never fails. But they emit carbon and pollute the air. So you are sacrificing clean.

If you optimize for clean and affordable, you are mostly building solar and wind. They are cheap, they are clean. But they are intermittent (Chapter 6), and storage is still expensive (Chapter 7). So you are sacrificing reliability unless you also build huge amounts of backup that you sometimes throw away.

If you optimize for reliable and clean, you are mostly building nuclear (Chapter 10), or nuclear plus storage plus oversized renewables plus a lot of transmission. You can do it. The lights stay on, the carbon emissions stay low. But the system is expensive. You are sacrificing affordable.

This is not a thought experiment. It is what every country in the world is actually navigating right now.

To understand how the trilemma works in practice, it helps to look at four real systems.

In 1973, the world experienced an oil shock. The Yom Kippur War led Arab oil-producing countries to cut off shipments to the United States and parts of Europe. Within a few months, the price of oil quadrupled. Gas stations rationed fuel. Industrial economies that had spent the previous decade getting deeply addicted to cheap Middle Eastern oil found themselves staring at the bill.

The French government, which had less domestic oil and gas than most of its neighbors, made a decision that would shape the country for the next fifty years. France would, as a national policy, get most of its electricity from nuclear power. Quickly. Before the next oil crisis.

The decision was called the Messmer Plan, after Prime Minister Pierre Messmer. Over the next fifteen years, France built more than fifty nuclear reactors. By 1990, over 70 percent of French electricity came from these reactors — a fraction unmatched by any other country in the world.

The result, for France, has been remarkable.

French electricity has been among the cleanest in the developed world for decades. Per kilowatt-hour, French electricity emits roughly a tenth of the carbon of American electricity, and a fifth of German electricity. French air around power plants is some of the cleanest in Europe.

French electricity has also been remarkably reliable. The country has not had a major blackout in decades. The grid weathered the 2022 European energy crisis better than its neighbors — when Russian gas was cut off, France’s nuclear reactors kept running.

But France paid a price. The construction of the nuclear fleet was enormously expensive. French electricity rates have historically been higher than in countries running on cheap coal or gas. The aging of the nuclear fleet is now a serious problem — most of those reactors are forty-plus years old, and they need expensive refurbishment or replacement. France’s nuclear waste storage problem is, like everyone else’s, unsolved.

When you hear that France “won” the energy game, the honest version is that France picked two corners of the trilemma — reliable and clean — and is still paying the bill for the third. The bill is real, and it is large. But France is also, fifty years later, one of the few major economies whose electricity is largely clean. Most of its neighbors cannot say the same.

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