Petawatt to Megawatt

It's a time trick. A petawatt laser concentrates a modest amount of energy (maybe 100–500 joules) into a pulse lasting 10–100 femtoseconds. Dividing a few hundred joules by 10⁻¹⁴ seconds gives you 10¹⁵–10¹⁶ watts — surpassing the Sun's 3.8 × 10²⁶ W is still far off, but these lasers do exceed total human power consumption by 100,000×. The catch: the total energy delivered is only enough to heat a cup of coffee.

Primarily for nuclear fusion research (compressing fuel pellets), particle acceleration (laser wakefield acceleration can produce electron beams rivalling billion-dollar synchrotrons), medical isotope production, and probing extreme states of matter found in stellar cores. The ELI (Extreme Light Infrastructure) project in Europe uses petawatt lasers to recreate conditions found in supernovae, helping astrophysicists study cosmic explosions in a lab.

Solar flares can briefly release 10–100 PW of electromagnetic radiation. The Chicxulub asteroid impact (the one that killed the dinosaurs) delivered roughly 4 × 10²³ watts during the few seconds of impact — about 100 million petawatts. Gamma-ray bursts top everything at 10²⁵–10²⁶ PW, briefly outshining the entire observable universe. Even supernovae "only" sustain about 10³⁶ PW for a few seconds at peak.

Building one costs $50–500 million. Operating costs are surprisingly modest per shot — each pulse uses only a few hundred joules (less than lifting an apple one meter), but the capacitor banks and cooling systems draw megawatts of continuous power. The NIF facility costs about $350 million per year to operate. Individual shots are "cheap" in energy terms but the infrastructure to achieve them is staggering.

In theory yes, but in practice current petawatt lasers are terrible weapons. They fire one pulse every few minutes to hours, require warehouse-sized buildings of equipment, and deliver total energy equivalent to a firecracker. Military-grade laser weapons focus on sustained power (100–300 kW continuous beams), not ultrashort pulses. A petawatt laser is a precision scientific scalpel, not a blunt instrument — brilliant for physics, useless for destruction.

In the US, roughly 750–1,000 homes (average consumption ~1.2 kW per home). In Europe, where usage is lower, 1 MW can serve 1,500–2,000 homes. But this is average — on a hot summer afternoon when everyone cranks AC, that number can drop to 300–400 homes. Grid planners must size for peak demand, not averages, which is why installed capacity far exceeds average load.

A small data center uses 1–5 MW; a large hyperscale facility (Google, AWS, Microsoft) draws 50–200 MW — some exceeding 300 MW. The entire US data center industry consumed about 17 GW in 2023, roughly 4% of national electricity. AI training clusters are pushing demand higher: a single large GPU cluster can draw 50–100 MW, and planned AI-focused campuses target 1 GW or more.

Onshore turbines typically rate 2–6 MW; the latest offshore monsters reach 14–16 MW per turbine. Vestas' V236-15.0 MW turbine has a rotor diameter of 236 meters — wider than two football fields. A single sweep of its blades can generate enough electricity for a UK household for two days. Capacity factors run 25–45% onshore and 40–55% offshore, so actual average output is roughly half the nameplate rating.

Most operating reactors produce 500–1,400 MW of electrical power. The world's largest, at France's Gravelines plant, has six reactors totalling 5,460 MW. Small Modular Reactors (SMRs) being developed target 50–300 MW each. Nuclear plants run at 85–95% capacity factor — far higher than wind (~35%) or solar (~25%) — meaning a 1,000 MW reactor actually delivers about 900 MW on average.

MW tells you the maximum instantaneous power the battery can deliver (how fast it can discharge), while MWh tells you total stored energy (how long it can sustain that output). A 100 MW / 400 MWh battery can deliver 100 MW for 4 hours, or 50 MW for 8 hours. Grid operators care about both: MW for handling sudden demand spikes, MWh for sustained backup during extended outages or evening solar fade.